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1
2 C and C++ XML Data Bindings {#mainpage}
3 ===========================
4
5 [TOC]
6
7 Introduction {#intro}
8 ============
9
10 This article presents a detailed overview of the gSOAP XML data bindings for C
11 and C++. The XML data bindings for C and C++ are extensively used with gSOAP
12 Web services to serialize C and C++ data in XML as part of the SOAP/XML Web
13 services payloads. Also REST XML with gSOAP relies on XML serialization of C
14 and C++ data via XML data bindings.
15
16 The major advantage of XML data bindings is that your application data is
17 always **type safe** in C and C++ by binding XML schema types to C/C++ types.
18 So integers in XML are bound to C integers, strings in XML are bound to C or
19 C++ strings, complex types in XML are bound to C structs or C++ classes, and so
20 on. The structured data you create and accept will fit the data model and is
21 **static type safe**. In other words, by leveraging strong typing in C/C++,
22 your XML data meets **XML schema validation requirements** and satisfies **XML
23 interoperability requirements**.
24
25 In fact, gSOAP data bindings are more powerful than simply representing C/C++
26 data in XML. The gSOAP tools implement true and tested **structure-preserving
27 serialization** of C/C++ data in XML, including the serialization of cyclic
28 graph structures with id-ref XML attributes. The gSOAP tools also generate
29 routines for deep copying and deep deletion of C/C++ data structures to
30 simplify memory management. In addition, C/C++ structures are deserialized
31 into managed memory, managed by the gSOAP `soap` context.
32
33 At the end of this article two examples are given to illustrate the application
34 of XML data bindings. The first simple example <i>`address.cpp`</i> shows how to use
35 wsdl2h to bind an XML schema to C++. The C++ application reads and writes an
36 XML file into and from a C++ "address book" data structure as a simple example.
37 The C++ data structure is a vector of address objects. The second example
38 <i>`graph.cpp`</i> shows how C++ data can be accurately serialized as a tree,
39 digraph, and cyclic graph in XML. The digraph and cyclic graph serialization
40 rules implement SOAP 1.1/1.2 multi-ref encoding with id-ref attributes to link
41 elements through IDREF XML references, creating a an XML graph with pointers to
42 XML nodes that preserves the structural integrity of the serialized C++ data.
43
44 These examples demonstrate XML data bindings only for relatively simple data
45 structures and types. The gSOAP tools support more than just these type of
46 structures to serialize in XML. There are practically no limits to the
47 serialization of C and C++ data types in XML.
48
49 Also the support for XML schema (XSD) components is unlimited. The wsdl2h tool
50 maps schemas to C and C++ using built-in intuitive mapping rules, while
51 allowing the mappings to be customized using a <i>`typemap.dat`</i> file with mapping
52 instructions for wsdl2h.
53
54 The information in this article is applicable to gSOAP 2.8.26 and greater that
55 support C++11 features. However, C++11 is not required. The material and the
56 examples in this article use plain C and C++, until the point where we
57 introduce C++11 smart pointers and scoped enumerations. While most of the
58 examples in this article are given in C++, the concepts also apply to C with
59 the exception of containers, smart pointers, classes and their methods. None
60 of these exceptions limit the use of the gSOAP tools for C in any way.
61
62 The data binding concepts described in this article were first envisioned in
63 1999 by Prof. Robert van Engelen at the Florida State University. An
64 implementation was created in 2000, named "stub/skeleton compiler". The first
65 articles on its successor version "gSOAP" appeared in 2002. The principle of
66 mapping XSD components to C/C++ types and vice versa is now widely adopted in
67 systems and programming languages, including Java web services and by C# WCF.
68
69 We continue to be committed to our goal to empower C/C++ developers with
70 powerful autocoding tools for XML. Our commitment started in the very early
71 days of SOAP by actively participating in
72 [SOAP interoperability testing](http://www.whitemesa.com/interop.htm),
73 participating in the development and testing of the
74 [W3C XML Schema Patterns for Databinding Interoperability](http://www.w3.org/2002/ws/databinding),
75 and continues by contributing to the development of
76 [OASIS open standards](https://www.oasis-open.org) in partnership with leading
77 IT companies in the world.
78
79 🔝 [Back to table of contents](#)
80
81 Notational Conventions {#conventions}
82 ======================
83
84 The typographical conventions used by this document are:
85
86 * `Courier` denotes C and C++ source code.
87
88 * <i>`Courier`</i> denotes XML content, JSON content, file and path names, and URIs.
89
90 * <b>`Courier`</b> denotes HTTP content, text file content, and shell commands with command line options and arguments.
91
92 The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
93 "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to
94 be interpreted as described in RFC-2119.
95
96 🔝 [Back to table of contents](#)
97
98 Mapping WSDL and XML schemas to C/C++ {#tocpp}
99 =====================================
100
101 To convert WSDL and XML schemas (XSD files) to code, we use the wsdl2h command
102 on the command line (or command prompt), after opening a terminal. The wsdl2h
103 command generates the data binding interface code that is saved to a special
104 Web services and data bindings interface header file with extension <i>`.h`</i>
105 that contains the WSDL service declarations and the data binding interface
106 declarations in a familiar C/C++ format:
107
108 wsdl2h [options] -o file.h ... XSD and WSDL files ...
109
110 This command converts WSDL and XSD files to C++ (or pure C with
111 <b>`wsdl2h -c`</b>) and saves the data binding interface to a interface header
112 file <i>`file.h`</i> that uses familiar C/C++ syntax extended with `//gsoap`
113 [directives](#directives) and annotations. Notational conventions are used in
114 the data binding interface to declare serializable C/C++ types and functions
115 for Web service operations.
116
117 The WSDL 1.1/2.0, SOAP 1.1/1.2, and XSD 1.0/1.1 standards are supported by the
118 gSOAP tools. In addition, the most popular WS specifications are also
119 supported, including WS-Addressing, WS-ReliableMessaging, WS-Discovery,
120 WS-Security, WS-Policy, WS-SecurityPolicy, and WS-SecureConversation.
121
122 This article focusses mainly on XML data bindings. XML data bindings for C/C++
123 bind XML schema types to C/C++ types. So integers in XML are bound to C
124 integers, strings in XML are bound to C or C++ strings, complex types in XML
125 are bound to C structs or C++ classes, and so on.
126
127 A data binding is dual, meaning supporting a two way direction for development.
128 Either you start with WSDLs and/or XML schemas that are mapped to equivalent
129 C/C++ types, or you start with C/C++ types that are mapped to XSD types.
130 Either way, the end result is that you can serialize C/C++ types in XML such
131 that your XML is an instance of XML schema(s) and is validated against these
132 schema(s).
133
134 This covers all of the following standard XSD components with their optional
135 attributes and properties:
136
137 XSD component | attributes and properties
138 -------------- | -------------------------
139 schema | targetNamespace, version, elementFormDefault, attributeFormDefault, defaultAttributes
140 attribute | name, ref, type, use, default, fixed, form, targetNamespace, wsdl:arrayType
141 element | name, ref, type, default, fixed, form, nillable, abstract, substitutionGroup, minOccurs, maxOccurs, targetNamespace
142 simpleType | name
143 complexType | name, abstract, mixed, defaultAttributesApply
144 all | *n/a*
145 choice | minOccurs, maxOccurs
146 sequence | minOccurs, maxOccurs
147 group | name, ref, minOccurs, maxOccurs
148 attributeGroup | name, ref
149 any | minOccurs, maxOccurs
150 anyAttribute | *n/a*
151
152 And also the following standard XSD directives are covered:
153
154 directive | description
155 ---------- | -----------
156 import | Imports a schema into the importing schema for referencing
157 include | Include schema component definitions into a schema
158 override | Override by replacing schema component definitions
159 redefine | Extend or restrict schema component definitions
160 annotation | Annotates a component
161
162 The XSD facets and their mappings to C/C++ are:
163
164 XSD facet | maps to
165 -------------- | -------
166 enumeration | `enum`
167 simpleContent | class/struct wrapper with `__item` member
168 complexContent | class/struct
169 list | `enum*` bitmask (`enum*` enumerates a bitmask up to 64 bits)
170 extension | class/struct inheritance/extension
171 restriction | `typedef` and class/struct inheritance/redeclaration
172 length | `typedef` with restricted content length annotation
173 minLength | `typedef` with restricted content length annotation
174 maxLength | `typedef` with restricted content length annotation
175 minInclusive | `typedef` with numerical value range restriction annotation
176 maxInclusive | `typedef` with numerical value range restriction annotation
177 minExclusive | `typedef` with numerical value range restriction annotation
178 maxExclusive | `typedef` with numerical value range restriction annotation
179 precision | `typedef` with pattern annotation (pattern used for output, but input is not validated)
180 scale | `typedef` with pattern annotation (pattern used for output, but input is not validated)
181 totalDigits | `typedef` with pattern annotation (pattern used for output, but input is not validated)
182 fractionDigits | `typedef` with pattern annotation (pattern used for output, but input is not validated)
183 pattern | `typedef` with pattern annotation (define `soap::fsvalidate` callback to validate patterns)
184 union | string with union of value
185
186 All primitive XSD types are supported, including but not limited to the
187 following XSD types:
188
189 XSD type | maps to
190 ---------------- | -------
191 any/anyType | `_XML` string with literal XML content (or enable DOM with wsdl2h option `-d`)
192 anyURI | string (i.e. `char*`, `wchar_t*`, `std::string`, `std::wstring`)
193 string | string (i.e. `char*`, `wchar_t*`, `std::string`, `std::wstring`)
194 boolean | `bool` (C++) or `enum xsd__boolean` (C)
195 byte | `char` (i.e. `int8_t`)
196 short | `short` (i.e. `int16_t`)
197 int | `int` (i.e. `int32_t`)
198 long | `LONG64` (i.e. `long long` and `int64_t`)
199 unsignedByte | `unsigned char` (i.e. `uint8_t`)
200 unsignedShort | `unsigned short` (i.e. `uint16_t`)
201 unsignedInt | `unsigned int` (i.e. `uint32_t`)
202 unsignedLong | `ULONG64` (i.e. `unsigned long long` and `uint64_t`)
203 float | `float`
204 double | `double`
205 integer | string or `#import "custom/int128.h"` to use 128 bit `xsd__integer`
206 decimal | string or `#import "custom/long_double.h"` to use `long double`
207 precisionDecimal | string
208 duration | string or `#import "custom/duration.h"` to use 64 bit `xsd__duration`
209 dateTime | `time_t` or `#import "custom/struct_tm.h"` to use `struct tm` for `xsd__dateTime`
210 time | string or `#import "custom/long_time.h"` to use 64 bit `xsd__time`
211 date | string or `#import "custom/struct_tm_date.h"` to use `struct tm` for `xsd__date`
212 hexBinary | special class/struct `xsd__hexBinary`
213 base64Binary | special class/struct `xsd__base64Binary`
214 QName | `_QName` string (URI normalization rules are applied)
215
216 All other primitive XSD types not listed above are mapped to strings, by
217 wsdl2h generating a `typedef` to string for these types. For example,
218 <i>`xsd:token`</i> is bound to a C++ or C string:
219
220 ~~~{.cpp}
221 typedef std::string xsd__token; // C++
222 typedef char *xsd__token; // C (wsdl2h option -c)
223 ~~~
224
225 This associates a compatible value space to the type with the appropriate XSD
226 type name used by the soapcpp2-generated serializers.
227
228 It is possible to remap types by adding the appropriate mapping rules to
229 <i>`typemap.dat`</i> as we will explain in more detail in the next section.
230
231 Imported custom serializers are intended to extend the C/C++ type bindings when
232 the default binding to string is not satisfactory to your taste and if the
233 target platform supports these C/C++ types. To add custom serializers to
234 <i>`typemap.dat`</i> for wsdl2h, see [adding custom serializers](#custom) below.
235
236 🔝 [Back to table of contents](#)
237
238 Using typemap.dat to customize data bindings {#typemap}
239 ============================================
240
241 Use a <i>`typemap.dat`</i> file to redefine namespace prefixes and to customize type
242 bindings for the the generated header files produced by the wsdl2h tool. The
243 <i>`typemap.dat`</i> is the default file processed by wsdl2h. Use <b>`wsdl2h -tfile.dat`</b>
244 option <b>`-tfile.dat`</b> to specify a different mapping file <i>`file.dat`</i>.
245
246 Declarations in <i>`typemap.dat`</i> can be broken up over multiple lines by
247 continuing on the next line by ending each line to be continued with a
248 backslash <b>`\`</b>. The limit is 4095 characters per line, whether the line is
249 broken up or not.
250
251 🔝 [Back to table of contents](#)
252
253 XML namespace bindings {#typemap1}
254 ----------------------
255
256 The wsdl2h tool generates C/C++ type declarations that use `ns1`, `ns2`, etc.
257 as schema-binding URI prefixes. These default prefixes are generated somewhat
258 arbitrarily for each schema targetNamespace URI, meaning that their ordering
259 may change depending on the WSDL and XSD order of processing with wsdl2h.
260
261 Therefore, it is **strongly recommended** to declare your own prefix for each
262 schema URI in <i>`typemap.dat`</i> to reduce maintaince effort of your code. This
263 is more robust when anticipating possible changes of the schema(s) and/or the
264 binding URI(s) and/or the tooling algorithms.
265
266 The first and foremost important thing to do is to define prefix-URI bindings
267 for our C/C++ code by adding the following line(s) to our <i>`typemap.dat`</i> or make
268 a copy of this file and add the line(s) that bind our choice of prefix name to
269 each URI:
270
271 prefix = "URI"
272
273 For example, to use `g` as a prefix for the "urn:graph" XML namespace:
274
275 g = "urn:graph"
276
277 This produces `g__name` C/C++ type names that are bound to the "urn:graph"
278 schema by association of `g` to the generated C/C++ types.
279
280 This means that <i>`<g:name xmlns:g="urn:graph">`</i> is parsed as an instance of a
281 `g__name` C/C++ type. Also <i>`<x:name xmlns:x="urn:graph">`</i> parses as an
282 instance of `g__name`, because the prefix <i>`x`</i> has the same URI value
283 <i>`urn:graph`</i>. Prefixes in XML have local scopes (like variables in a block).
284
285 The first run of wsdl2h will reveal the XML namespace URIs, so you do not need
286 to search WSDLs and XSD files for all of the target namespaces. Just copy them
287 from the generated header file after the first run into <i>`typemap.dat`</i> for
288 editing.
289
290 @note Only define a namespace prefix once in <i>`typemap.dat`</i>. That is, do not
291 use the same prefix for multiple XML namespace URIs. This is to avoid
292 namespace conflicts that may cause failed builds and failures in XML parsing
293 and XML schema validation.
294
295 🔝 [Back to table of contents](#)
296
297 XSD type bindings {#typemap2}
298 -----------------
299
300 Custom C/C++ type bindings can be declared in <i>`typemap.dat`</i> to associate C/C++
301 types with specific schema types. These type bindings have four parts:
302
303 prefix__type = declaration | use | ptr-use
304
305 where
306
307 - <b>`prefix__type`</b> is the schema type to be customized (the <b>`prefix__type`</b> name
308 uses the common double underscore naming convention);
309
310 - <b>`declaration`</b> declares the C/C++ type in the wsdl2h-generated header file.
311 This part can be empty if no explicit declaration is needed;
312
313 - <b>`use`</b> is an optional part that specifies how the C/C++ type is used in the
314 code. When omitted, it is the same as <b>`prefix__type`</b>;
315
316 - <b>`ptr-use`</b> is an optional part that specifies how the type is used as a pointer
317 type. By default it is the <b>`use`</b> type name with a <b>`*`</b> or C++11
318 <b>`std::shared_ptr<type>`</b> when enabled (see further below). If <b>`use`</b> is already a
319 pointer type by the presence of a <b>`*`</b> in the <b>`use`</b> part, then the default
320 <b>`ptr-use`</b> type is the same as the <b>`use`</b> type (that is, no double
321 pointers <b>`**`</b> will be created in this case).
322
323 For example, to map <i>`xsd:duration`</i> to a `long long` (`LONG64`) type that holds
324 millisecond duration values, we can use the custom serializer declared in
325 <i>`gsoap/custom/duration.h`</i> by adding the following line to <i>`typemap.dat`</i>:
326
327 xsd__duration = #import "custom/duration.h"
328
329 Here, we omitted the second and third parts, because `xsd__duration` is the
330 name that wsdl2h uses for this type in our generated code so we should leave
331 the <b>`use`</b> part unspecified. The third part is omitted to let wsdl2h use
332 `xsd__duration *` for pointers or `std::shared_ptr<xsd__duration>` if smart
333 pointers are enabled.
334
335 To map <i>`xsd:string`</i> to `wchar_t*` wide strings for C source code output:
336
337 xsd__string = | wchar_t* | wchar_t*
338
339 For C++ we can use the `std::wstring` wide string:
340
341 xsd__string = | std::wstring
342
343 Note that the first part is empty, because these types do not require a
344 declaration. A <b>`ptr-use`</b> part is also defined for `wchar_t*`, but this
345 is actually needed because the wsdl2h tool recognizes that the <b>`use`</b>
346 part `wchar_t*` is already a pointer. By contrast, when using 8-bit strings,
347 it is recommended to use the `SOAP_C_UTFSTRING` flag to enable UTF-8 formatted
348 strings.
349
350 When the <b>`ptr-use`</b> part is not specified, it will be auto-generated
351 as pointer `T*` for <b>`use`</b> type `T` or `std::shared_ptr<T>` when
352 the variable `$POINTER = std::shared`, see
353 [the special variables $CONTAINER, $POINTER, $SIZE and $OPTIONAL](#typemap5).
354
355 The <b>`declaration`</b> part need not be empty, for example if a type must be
356 declared. For example:
357
358 xsd__string = typedef std::string mystring; | mystring | std::optional<mystring>
359
360 When a auto-generated <b>`declaration`</b> should be preserved but the
361 <b>`use`</b> or <b>`ptr-use`</b> parts must be redefined, then we use an
362 ellipsis for the <b>`declaration`</b> part:
363
364 prefix__type = ... | use | ptr-use
365
366 The <b>`ptr-use`</b> part is also useful to map schema polymorphic types to C
367 types for example, where we need to be able to both handle a base type and its
368 extensions as per schema extensibility. Say we have a base type called
369 <i>`ns:base`</i> that is extended, then we can remap this to a C type that
370 permits referening the extended types via a `void*` as follows:
371
372 ns__base = ... | int __type_base; void*
373
374 such that `__type_base` and `void*` will be used to (de)serialize any data
375 type, including base and its derived types. The `__type_base` integer is set
376 to a `SOAP_TYPE_T` value to indicate what type of data the `void*` pointer
377 points to.
378
379 🔝 [Back to table of contents](#)
380
381 Custom serializers for XSD types {#custom}
382 --------------------------------
383
384 In the previous part we saw how a custom serializer is used to bind
385 <i>`xsd:duration`</i> to a `long long` (`LONG64` or `int64_t`) type to store millisecond
386 duration values:
387
388 xsd__duration = #import "custom/duration.h"
389
390 The `xsd__duration` type is an alias of `long long` (`LONG64` or `int64_t`).
391
392 While wsdl2h will use this binding declared in <i>`typemap.dat`</i>
393 automatically, you will also need to compile <i>`gsoap/custom/duration.c`</i>.
394 Each custom serializer has an interface header file to be imported into another
395 interface header file that declares the custom type for soapcpp2 and a
396 serializer implementation file written in C, which should be compiled with the
397 application. You can compile these in C++ (rename files to <i>`.cpp`</i> if
398 needed).
399
400 A custom serializer is declared in an interface header file for soapcpp2 using
401 `extern typedef`. The typedef name declared is serializable, whereas the
402 type on which it is based is not serializable. This declaration can be
403 combined with `volatile` when the type should not be redeclared, see
404 [volatile classes and structs](#toxsd9-2). For example, the custom serializer
405 for `struct tm` is the type `xsd__datetime` declared as follows in
406 `gsoap/custom/struct_tm.h`:
407
408 ~~~{.cpp}
409 extern typedef volatile struct tm
410 {
411 int tm_sec; ///< seconds (0 - 60)
412 int tm_min; ///< minutes (0 - 59)
413 int tm_hour; ///< hours (0 - 23)
414 int tm_mday; ///< day of month (1 - 31)
415 int tm_mon; ///< month of year (0 - 11)
416 int tm_year; ///< year - 1900
417 int tm_wday; ///< day of week (Sunday = 0) (NOT USED)
418 int tm_yday; ///< day of year (0 - 365) (NOT USED)
419 int tm_isdst; ///< is summer time in effect?
420 char* tm_zone; ///< abbreviation of timezone (NOT USED)
421 } xsd__dateTime;
422 ~~~
423
424 Another example is `xsd__duration` as a custom serializer for the C++11 type
425 `std::chrono::nanoseconds`:
426
427 ~~~{.cpp}
428 extern typedef class std::chrono::nanoseconds xsd__duration;
429 ~~~
430
431 Next, we present all pre-defined custom serializers that are available to you.
432
433 🔝 [Back to table of contents](#)
434
435 ### xsd:integer {#custom-1}
436
437 The wsdl2h tool maps <i>`xsd:integer`</i> to a string by default. To map <i>`xsd:integer`</i> to
438 the 128 bit big int type `__int128_t`:
439
440 xsd__integer = #import "custom/int128.h"
441
442 The `xsd__integer` type is an alias of `__int128_t`.
443
444 @warning Beware that the <i>`xsd:integer`</i> value space of integers is in principle
445 unbounded and values can be of arbitrary length. A value range fault
446 `SOAP_TYPE` (value exceeds native representation) or `SOAP_LENGTH` (value
447 exceeds range bounds) will be thrown by the deserializer if the value is out of
448 range.
449
450 Other XSD integer types that are restrictions of <i>`xsd:integer`</i>, are
451 <i>`xsd:nonNegativeInteger`</i> and <i>`xsd:nonPositiveInteger`</i>, which are further restricted
452 by <i>`xsd:positiveInteger`</i> and <i>`xsd:negativeInteger`</i>. To bind these types to
453 `__int128_t` add the following definitions to <i>`typemap.dat`</i>:
454
455 xsd__nonNegativeInteger = typedef xsd__integer xsd__nonNegativeInteger 0 : ;
456 xsd__nonPositiveInteger = typedef xsd__integer xsd__nonPositiveInteger : 0 ;
457 xsd__positiveInteger = typedef xsd__integer xsd__positiveInteger 1 : ;
458 xsd__negativeInteger = typedef xsd__integer xsd__negativeInteger : -1 ;
459
460 Or simply uncomment these definitions in <i>`typemap.dat`</i> when you are using the
461 latest gSOAP releases.
462
463 @note If `__int128_t` 128 bit integers are not supported on your platform and if it
464 is certain that <i>`xsd:integer`</i> values are within 64 bit value bounds for your
465 application's use, then you can map this type to `LONG64`:
466
467 xsd__integer = typedef LONG64 xsd__integer;
468
469 @note Again, a value range fault `SOAP_TYPE` or `SOAP_LENGTH` will be thrown by
470 the deserializer if the value is out of range.
471
472 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/int128.c`</i> with your project.
473
474 @see Section [numerical types](#toxsd5).
475
476 🔝 [Back to table of contents](#)
477
478 ### xsd:decimal {#custom-2}
479
480 The wsdl2h tool maps <i>`xsd:decimal`</i> to a string by default. To map <i>`xsd:decimal`</i> to
481 extended precision floating point:
482
483 xsd__decimal = #import "custom/long_double.h" | long double
484
485 By contrast to all other custom serializers, this serializer enables `long
486 double` natively without requiring a new binding name (`xsd__decimal` is NOT
487 defined).
488
489 If your system supports <i>`quadmath.h`</i> quadruple precision floating point
490 `__float128`, you can map <i>`xsd:decimal`</i> to `xsd__decimal` that is an alias of
491 `__float128`:
492
493 xsd__decimal = #import "custom/float128.h"
494
495 @warning Beware that <i>`xsd:decimal`</i> is in principle a decimal value with arbitraty
496 lengths. A value range fault `SOAP_TYPE` will be thrown by the deserializer if
497 the value is out of range.
498
499 In the XML payload the special values <i>`INF`</i>, <i>`-INF`</i>, <i>`NaN`</i>
500 represent plus or minus infinity and not-a-number, respectively.
501
502 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/long_double.c`</i> with your
503 project.
504
505 @see Section [numerical types](#toxsd5).
506
507 🔝 [Back to table of contents](#)
508
509 ### xsd:dateTime {#custom-3}
510
511 The wsdl2h tool maps <i>`xsd:dateTime`</i> to `time_t` by default.
512
513 The trouble with `time_t` when represented as 32 bit `long` integers is that it
514 is limited to dates between 1970 and 2038. A 64 bit `time_t` is safe to use if
515 the target platform supports it, but lack of 64 bit `time_t` portability may
516 still cause date range issues.
517
518 For this reason `struct tm` should be used to represent wider date ranges. This
519 custom serializer avoids using date and time information in `time_t`. You get
520 the raw date and time information. You only lose the day of the week
521 information. It is always Sunday (`tm_wday=0`).
522
523 To map <i>`xsd:dateTime`</i> to `xsd__dateTime` which is an alias of `struct tm`:
524
525 xsd__dateTime = #import "custom/struct_tm.h"
526
527 If the limited date range of `time_t` is not a problem but you want to increase
528 the time precision with fractional seconds, then we suggest to map <i>`xsd:dateTime`</i>
529 to `struct timeval`:
530
531 xsd__dateTime = #import "custom/struct_timeval.h"
532
533 If the limited date range of `time_t` is not a problem but you want to use the
534 C++11 time point type `std::chrono::system_clock::time_point` (which internally
535 uses `time_t`):
536
537 xsd__dateTime = #import "custom/chrono_time_point.h"
538
539 Again, we should make sure that the dates will not exceed the date range when
540 using the default `time_t` binding for <i>`xsd:dateTime`</i> or when binding
541 <i>`xsd:dateTime`</i> to `struct timeval` or to `std::chrono::system_clock::time_point`.
542 These are safe to use in applications that use <i>`xsd:dateTime`</i> to record date
543 stamps within a given window. Otherwise, we recommend the `struct tm` custom
544 serializer.
545
546 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/struct_tm.c`</i> with your
547 project.
548
549 You could even map <i>`xsd:dateTime`</i> to a plain string (use `char*` with C and
550 `std::string` with C++). For example:
551
552 xsd__dateTime = | char*
553
554 @see Section [date and time types](#toxsd7).
555
556 🔝 [Back to table of contents](#)
557
558 ### xsd:date {#custom-4}
559
560 The wsdl2h tool maps <i>`xsd:date`</i> to a string by default. We can map <i>`xsd:date`</i> to
561 `struct tm`:
562
563 xsd__date = #import "custom/struct_tm_date.h"
564
565 The `xsd__date` type is an alias of `struct tm`. The serializer ignores the
566 time part and the deserializer only populates the date part of the struct,
567 setting the time to 00:00:00. There is no unreasonable limit on the date range
568 because the year field is stored as an integer (`int`).
569
570 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/struct_tm_date.c`</i> with your
571 project.
572
573 @see Section [date and time types](#toxsd7).
574
575 🔝 [Back to table of contents](#)
576
577 ### xsd:time {#custom-5}
578
579 The wsdl2h tool maps <i>`xsd:time`</i> to a string by default. We can map <i>`xsd:time`</i> to
580 an `unsigned long long` (`ULONG64` or `uint64_t`) integer with microsecond time
581 precision:
582
583 xsd__time = #import "custom/long_time.h"
584
585 This type represents 00:00:00.000000 to 23:59:59.999999, from `0` to an upper
586 bound of `86399999999`. A microsecond resolution means that a 1 second
587 increment requires an increment of 1000000 in the integer value. The serializer
588 adds a UTC time zone.
589
590 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/long_time.c`</i> with your
591 project.
592
593 @see Section [date and time types](#toxsd7).
594
595 🔝 [Back to table of contents](#)
596
597 ### xsd:duration {#custom-6}
598
599 The wsdl2h tool maps <i>`xsd:duration`</i> to a string by default, unless <i>`xsd:duration`</i>
600 is mapped to a `long long` (`LONG64` or `int64_t`) type with with millisecond
601 (ms) time duration precision:
602
603 xsd__duration = #import "custom/duration.h"
604
605 The `xsd__duration` type is a 64 bit signed integer that can represent
606 106,751,991,167 days forwards (positive) and backwards (negative) in time in
607 increments of 1 ms (1/1000 of a second).
608
609 Rescaling of the duration value by may be needed when adding the duration value
610 to a `time_t` value, because `time_t` may or may not have a seconds resolution,
611 depending on the platform and possible changes to `time_t`.
612
613 Rescaling is done automatically when you add a C++11 `std::chrono::nanoseconds`
614 value to a `std::chrono::system_clock::time_point` value. To use
615 `std::chrono::nanoseconds` as <i>`xsd:duration`</i>:
616
617 xsd__duration = #import "custom/chrono_duration.h"
618
619 This type can represent 384,307,168 days (2^63 nanoseconds) forwards and
620 backwards in time in increments of 1 ns (1/1,000,000,000 of a second).
621
622 Certain observations with respect to receiving durations in years and months
623 apply to both of these serializer decoders for <i>`xsd:duration`</i>.
624
625 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/duration.c`</i> with your
626 project.
627
628 @see Section [time duration types](#toxsd8).
629
630 🔝 [Back to table of contents](#)
631
632 Custom Qt serializers for XSD types {#qt}
633 -----------------------------------
634
635 The gSOAP distribution includes several custom serializers for Qt types. Also
636 Qt container classes are supported, see
637 [the special variables $CONTAINER, $POINTER, $SIZE and $OPTIONAL](#typemap5).
638
639 This feature requires gSOAP 2.8.34 or higher and Qt 4.8 or higher.
640
641 Each Qt custom serializer has an interface header file for soapcpp2 and a C++
642 implementation file to be compiled with your project.
643
644 Other Qt primitive types that are Qt `typedef`s of C/C++ types do not require a
645 custom serializer.
646
647 🔝 [Back to table of contents](#)
648
649 ### xsd:string {#qt-1}
650
651 To use Qt strings instead of C++ strings, add the following definition to
652 <i>`typemap.dat`</i>:
653
654 xsd__string = #import "custom/qstring.h"
655
656 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qstring.cpp`</i> with your
657 project.
658
659 🔝 [Back to table of contents](#)
660
661 ### xsd:base64Binary {#qt-2}
662
663 To use Qt byte arrays for <i>`xsd:base64Binary`</i> instead of the
664 `xsd__base64Binary` class, add the following definition to <i>`typemap.dat`</i>:
665
666 xsd__base64Binary = #import "custom/qbytearray_base64.h"
667
668 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qbytearray_base64.cpp`</i> with
669 your project.
670
671 🔝 [Back to table of contents](#)
672
673 ### xsd:hexBinary {#qt-3}
674
675 To use Qt byte arrays for <i>`xsd:hexBinary`</i> instead of the `xsd__base64Binary`
676 class, add the following definition to <i>`typemap.dat`</i>:
677
678 xsd__hexBinary = #import "custom/qbytearray_hex.h"
679
680 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qbytearray_hex.cpp`</i> with
681 your project.
682
683 🔝 [Back to table of contents](#)
684
685 ### xsd:dateTime {#qt-4}
686
687 To use Qt QDateTime for <i>`xsd:dateTime`</i>, add the following definition to
688 <i>`typemap.dat`</i>:
689
690 xsd__dateTime = #import "custom/datetime.h"
691
692 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qdatetime.cpp`</i> with
693 your project.
694
695 🔝 [Back to table of contents](#)
696
697 ### xsd:date {#qt-5}
698
699 To use Qt QDate for <i>`xsd:date`</i>, add the following definition to
700 <i>`typemap.dat`</i>:
701
702 xsd__date = #import "custom/qdate.h"
703
704 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qdate.cpp`</i> with your
705 project.
706
707 🔝 [Back to table of contents](#)
708
709 ### xsd:time {#qt-6}
710
711 To use Qt QDate for <i>`xsd:time`</i>, add the following definition to
712 <i>`typemap.dat`</i>:
713
714 xsd__time = #import "custom/qtime.h"
715
716 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qtime.cpp`</i> with your
717 project.
718
719 🔝 [Back to table of contents](#)
720
721 Class/struct member additions {#typemap3}
722 -----------------------------
723
724 All generated classes and structs can be augmented with additional
725 members such as methods, constructors and destructors, and private members:
726
727 prefix__type = $ member-declaration
728
729 For example, we can add method declarations and private members to a class, say
730 `ns__record` as follows:
731
732 ns__record = $ ns__record(const ns__record &); // copy constructor
733 ns__record = $ void print(); // a print method
734 ns__record = $ private: int status; // a private member
735
736 Method declarations cannot include any code, because soapcpp2's input permits
737 only type declarations, not code.
738
739 🔝 [Back to table of contents](#)
740
741 Replacing XSD types by equivalent alternatives {#typemap4}
742 ----------------------------------------------
743
744 Type replacements can be given to replace one type entirely with another given
745 type:
746
747 prefix__type1 == prefix__type2
748
749 This replaces all `prefix__type1` by `prefix__type2` in the wsdl2h output.
750
751 @warning Do not agressively replace types, because this can cause XML schema
752 validation to fail when a value-type mismatch is encountered in the XML input.
753 Therefore, only replace similar types with other similar types that are wider
754 (e.g. `short` by `int` and `float` by `double`).
755
756 🔝 [Back to table of contents](#)
757
758 The special variables $CONTAINER, $POINTER, $SIZE and $OPTIONAL {#typemap5}
759 ---------------------------------------------------------------
760
761 The <i>`typemap.dat`</i> <b>`$CONTAINER`</b> variable defines the container type to use in
762 the wsdl2h-generated declarations for C++, which is `std::vector` by default.
763 For example, to use `std::list` as the container in the wsdl2h-generated
764 declarations we add the following line to <i>`typemap.dat`</i>:
765
766 $CONTAINER = std::list
767
768 Also a Qt container can be used instead of the default `std::vector`, for
769 example `QVector`:
770
771 [
772 #include <QVector>
773 ]
774 $CONTAINER = QVector
775
776 To remove containers, use <b>`wsdl2h -s`</b>. This also removes `std::string`,
777 but you can re-introduce `std::string` with
778 <b>`xsd__string = | std::string`</b> in <i>`typemap.dat`</i>.
779
780 The <i>`typemap.dat`</i> <b>`$POINTER`</b> variable defines the smart pointer to use in the
781 wsdl2h-generated declarations for C++, which replaces the use of `*` pointers.
782 For example:
783
784 $POINTER = std::shared_ptr
785
786 Not all pointers in the generated output are replaced by smart pointers by
787 wsdl2h, such as pointers as union members and pointers as struct/class members
788 that point to arrays of values.
789
790 @note The standard smart pointer `std::shared_ptr` is generally safe to use.
791 Other smart pointers such as `std::unique_ptr` and `std::auto_ptr` may cause
792 compile-time errors when classes have smart pointer members but no copy
793 constructor (a default copy constructor). A copy constructor is required for
794 non-shared smart pointer copying or swapping.
795
796 Alternatives to `std::shared_ptr` of the form `NAMESPACE::shared_ptr` can be
797 assigned to <b>`$POINTER`</b> when the namespace `NAMESPACE` also implements
798 `NAMESPACE::make_shared` and when the shared pointer class provides `reset()`
799 and`get()` methods and the dereference operator. For example Boost
800 `boost::shared_ptr`:
801
802 [
803 #include <boost/shared_ptr.hpp>
804 ]
805 $POINTER = boost::shared_ptr
806
807 The user-defined content between <b>`[`</b> and <b>`]`</b> ensures that we include the Boost
808 header files that are needed to support `boost::shared_ptr` and
809 `boost::make_shared`.
810
811 The variable <b>`$SIZE`</b> defines the type of array sizes, which is `int` by
812 default. For example, to change array size types to `size_t`:
813
814 $SIZE = size_t
815
816 Permissible types are `int` and `size_t`. This variable does not affect the
817 size of dynamic arrays, `xsd__hexBinary` and `xsd__base64Binary` types, which
818 is always `int`.
819
820 When C++17 is enabled with wsdl2h and soapcpp2 option <b>`-c++17`</b>, you can
821 also semi-automatically enable `std::optional` declarations with optional class
822 and structure member variables. This means that `std::optional` is used
823 instead of a (smart) pointer to make a member optional.
824
825 To enable `std::optional` with member variables that are primitive types,
826 `typedef`, and `enum` automatically:
827
828 $OPTIONAL = std::optional
829
830 Local unnamed simpleType restrictions may not adopt the specified optional type
831 and still use pointers instead. This limitation may be lifted in a future
832 release.
833
834 🔝 [Back to table of contents](#)
835
836 User-defined content {#typemap6}
837 --------------------
838
839 Any other content to be generated by wsdl2h can be included in <i>`typemap.dat`</i> by
840 enclosing it within brackets <b>`[`</b> and <b>`]`</b> anywhere in the <i>`typemap.dat`</i> file.
841 Each of the two brackets must appear at the start of a new line.
842
843 For example, we can add an `#import "wsa5.h"` to the wsdl2h-generated output as
844 follows:
845
846 [
847 #import "import/wsa5.h"
848 ]
849
850 which emits the `#import "import/wsa5.h"` literally at the start of the
851 wsdl2h-generated header file.
852
853 🔝 [Back to table of contents](#)
854
855 Mapping C/C++ to XML schema {#toxsd}
856 ===========================
857
858 The soapcpp2 command generates the data binding implementation code from a data
859 binding interface <i>`file.h`</i>:
860
861 soapcpp2 [options] file.h
862
863 where <i>`file.h`</i> is a interface header file that declares the XML data
864 binding interface. The <i>`file.h`</i> is typically generated by wsdl2h, but
865 you can also declare one yourself. If so, add `//gsoap`
866 [directives](#directives) and declare in this file all our C/C++ types you want
867 to serialize in XML.
868
869 You can also declare functions that will be converted to Web service operations
870 by soapcpp2. Global function declarations define service operations, which are
871 of the form:
872
873 ~~~{.cpp}
874 int prefix__func(arg1, arg2, ..., argn, result);
875 ~~~
876
877 where `arg1`, `arg2`, ..., `argn` are formal argument declarations of the input
878 and `result` is a formal argument for the output, which must be a pointer or
879 reference to the result object to be populated. More information on declaring
880 and implementing service operation functions can be found in the
881 [gSOAP user guide.](../../guide/html/index.html)
882
883 🔝 [Back to table of contents](#)
884
885 Overview of serializable C/C++ types {#toxsd1}
886 ------------------------------------
887
888 The following C/C++ types are supported by soapcpp2 and mapped to XSD types
889 and constructs. See the subsections below for more details or follow the links.
890
891 🔝 [Back to table of contents](#)
892
893 ### List of Boolean types
894
895 Boolean Type | Notes
896 ----------------------------- | -----
897 `bool` | C++ bool
898 `enum xsd__boolean` | C alternative to C++ `bool` with `false_` and `true_`
899
900 @see Section [C++ bool and C alternative](#toxsd3).
901
902 🔝 [Back to table of contents](#)
903
904 ### List of enumeration and bitmask types
905
906 Enumeration Type | Notes
907 ----------------------------- | -----
908 `enum` | enumeration
909 `enum class` | C++11 scoped enumeration, requires `soapcpp2 -c++11`
910 `enum*` | a bitmask that enumerates values 1, 2, 4, 8, ...
911 `enum* class` | C++11 scoped enumeration bitmask, requires `soapcpp2 -c++11`
912
913 @see Section [enumerations and bitmasks](#toxsd4).
914
915 🔝 [Back to table of contents](#)
916
917 ### List of numerical types
918
919 Numerical Type | Notes
920 ----------------------------- | -----
921 `char` | byte
922 `short` | 16 bit integer
923 `int` | 32 bit integer
924 `long` | 32 bit integer
925 `LONG64` | 64 bit integer
926 `xsd__integer` | 128 bit integer, use `#import "custom/int128.h"`
927 `long long` | same as `LONG64`
928 `unsigned char` | unsigned byte
929 `unsigned short` | unsigned 16 bit integer
930 `unsigned int` | unsigned 32 bit integer
931 `unsigned long` | unsigned 32 bit integer
932 `ULONG64` | unsigned 64 bit integer
933 `unsigned long long` | same as `ULONG64`
934 `int8_t` | same as `char`
935 `int16_t` | same as `short`
936 `int32_t` | same as `int`
937 `int64_t` | same as `LONG64`
938 `uint8_t` | same as `unsigned char`
939 `uint16_t` | same as `unsigned short`
940 `uint32_t` | same as `unsigned int`
941 `uint64_t` | same as `ULONG64`
942 `size_t` | transient type (not serializable)
943 `float` | 32 bit float
944 `double` | 64 bit float
945 `long double` | extended precision float, use `#import "custom/long_double.h"`
946 `xsd__decimal` | `quadmath.h` library 128 bit quadruple precision float, use `#import "custom/float128.h"`
947 `typedef` | declares a type name, with optional value range and string length bounds
948
949 @see Section [numerical types](#toxsd5).
950
951 🔝 [Back to table of contents](#)
952
953 ### List of string types
954
955 String Type | Notes
956 ----------------------------- | -----
957 `char*` | string (may contain UTF-8 with flag `SOAP_C_UTFSTRING`)
958 `wchar_t*` | wide string
959 `std::string` | C++ string (may contain UTF-8 with flag `SOAP_C_UTFSTRING`)
960 `std::wstring` | C++ wide string
961 `char[N]` | fixed-size string, requires `soapcpp2 -b`
962 `_QName` | normalized QName content
963 `_XML` | literal XML string content with wide characters in UTF-8
964 `typedef` | declares a new string type name, may restrict string length
965
966 @see Section [string types](#toxsd6).
967
968 🔝 [Back to table of contents](#)
969
970 ### List of date and time types
971
972 Date and Time Type | Notes
973 --------------------------------------- | -----
974 `time_t` | date and time point since epoch
975 `struct tm` | date and time point, use `#import "custom/struct_tm.h"`
976 `struct tm` | date point, use `#import "custom/struct_tm_date.h"`
977 `struct timeval` | date and time point, use `#import "custom/struct_timeval.h"`
978 `unsigned long long` | time point in microseconds, use `#import "custom/long_time.h"`
979 `std::chrono::system_clock::time_point` | date and time point, use `#import "custom/chrono_time_point.h"`
980
981 @see Section [date and time types](#toxsd7).
982
983 🔝 [Back to table of contents](#)
984
985 ### List of time duration types
986
987 Time Duration Type | Notes
988 ----------------------------- | -----
989 `long long` | duration in milliseconds, use `#import "custom/duration.h"`
990 `std::chrono::nanoseconds` | duration in nanoseconds, use `#import "custom/chrono_duration.h"`
991
992 @see Section [time duration types](#toxsd8).
993
994 🔝 [Back to table of contents](#)
995
996 ### List of classes, structs, unions, pointers, containers, and arrays
997
998 Classes, Structs, and Members | Notes
999 ----------------------------- | -----
1000 `class` | C++ class with single inheritance only
1001 `struct` | C struct or C++ struct without inheritance
1002 `std::shared_ptr<T>` | C++11 smart shared pointer
1003 `std::unique_ptr<T>` | C++11 smart pointer
1004 `std::auto_ptr<T>` | C++ smart pointer
1005 `std::deque<T>` | use `#import "import/stldeque.h"`
1006 `std::list<T>` | use `#import "import/stllist.h"`
1007 `std::vector<T>` | use `#import "import/stlvector.h"`
1008 `std::set<T>` | use `#import "import/stlset.h"`
1009 `template<T> class` | a container with `begin()`, `end()`, `size()`, `clear()`, and `insert()` methods
1010 `T*` | pointer to data of type `T`
1011 `T*` | as a class or struct member: points to data of type `T` or array of `T` with member `__size`
1012 `T[N]` | as a class or struct member: fixed-size array of type `T`
1013 `union` | as a class or struct member: requires a variant selector member `__union`
1014 `void*` | as a class or struct member: requires a `__type` member to indicate the type of object pointed to
1015
1016 @see Section [classes and structs](#toxsd9).
1017
1018 🔝 [Back to table of contents](#)
1019
1020 ### List of special classes and structs
1021
1022 Special Classes and Structs | Notes
1023 ----------------------------- | -----
1024 Special Array class/struct | single and multidimensional SOAP Arrays
1025 Special Wrapper class/struct | complexTypes with simpleContent, wraps `__item` member
1026 `xsd__hexBinary` | binary content
1027 `xsd__base64Binary` | binary content and optional DIME/MIME/MTOM attachments
1028 `xsd__anyType` | DOM elements, use `#import "dom.h"`
1029 `@xsd__anyAttribute` | DOM attributes, use `#import "dom.h"`
1030
1031 @see Section [special classes and structs](#toxsd10).
1032
1033 🔝 [Back to table of contents](#)
1034
1035 Colon notation versus name prefixing with XML tag name translation {#toxsd2}
1036 ------------------------------------------------------------------
1037
1038 To bind C/C++ type names to XSD types, a simple form of name prefixing is used
1039 by the gSOAP tools by prepending the XML namespace prefix to the C/C++ type
1040 name with a pair of undescrores. This also ensures that name clashes cannot
1041 occur when multiple WSDL and XSD files are converted to C/C++. Also, C++
1042 namespaces are not sufficiently rich to capture XML schema namespaces
1043 accurately, for example when class members are associated with schema elements
1044 defined in another XML namespace and thus the XML namespace scope of the
1045 member's name is relevant, not just its type.
1046
1047 However, from a C/C++ centric point of view this can be cumbersome. Therefore,
1048 colon notation is an alternative to physically augmenting C/C++ names with
1049 prefixes.
1050
1051 For example, the following class uses colon notation to bind the `record` class
1052 to the <i>`urn:types`</i> schema:
1053
1054 ~~~{.cpp}
1055 //gsoap ns schema namespace: urn:types
1056 class ns:record // binding 'ns:' to a type name
1057 {
1058 public:
1059 std::string name;
1060 uint64_t SSN;
1061 ns:record *spouse; // using 'ns:' with the type name
1062 ns:record(); // using 'ns:' here too
1063 ~ns:record(); // and here
1064 };
1065 ~~~
1066
1067 The colon notation is stripped away by soapcpp2 when generating the data
1068 binding implementation code for our project. So the final code just uses
1069 `record` to identify this class and its constructor/destructor.
1070
1071 When using colon notation make sure to be consistent and not use colon notation
1072 mixed with prefixed forms. The qualified name `ns:record` differs from `ns__record`,
1073 because `ns:record` is compiled to an unqualified `record` name in the source
1074 code output by the soapcpp2 tool.
1075
1076 Colon notation also facilitates overruling the elementFormDefault and
1077 attributeFormDefault declaration that is applied to local elements and
1078 attributes, when declared as members of classes, structs, and unions. For more
1079 details, see [qualified and unqualified members](#toxsd9-6).
1080
1081 A C/C++ identifier name (a type name, member name, function name, or parameter
1082 name) is translated to an XML tag name by the following rules:
1083
1084 - Two leading underscores indicates that the identifier name has no XML tag
1085 name, i.e. this name is not visible in XML and is not translated.
1086
1087 - A leading underscore is removed, but the underscore indicates that: **a**) a
1088 struct/class member name or parameter name has a wildcard XML tag name (i.e.
1089 matches any XML tag), or **b**) a type name that has a
1090 [document root element definition](#toxsd9-7).
1091
1092 - Trailing underscores are removed (i.e. trailing underscores can be used to
1093 avoid name clashes with keywords).
1094
1095 - Underscores within names are translated to hyphens (hyphens are more common
1096 in XML tag names).
1097
1098 - `_USCORE` is translated to an underscore in the translated XML tag name.
1099
1100 - `_DOT` is translated to a dot (<i>`.`</i>) in the translated XML tag name.
1101
1102 - `_xHHHH` is translated to the Unicode character with code point HHHH (hex).
1103
1104 - C++11 Unicode identifier name characters in UTF-8 are translated as-is.
1105
1106 For example, the C/C++ namespace qualified identifier name `s_a__my_way` is
1107 translated to the XML tag name <i>`s-a:my-way`</i> by translating the prefix `s_a`
1108 and the local name `my_way`.
1109
1110 Struct/class member and parameter name translation can be overruled by using
1111 [backtick XML tags](#toxsd9-5-1) (with gSOAP 2.8.30 and greater).
1112
1113 🔝 [Back to table of contents](#)
1114
1115 C++ bool and C alternative {#toxsd3}
1116 --------------------------
1117
1118 The C++ `bool` type is bound to built-in XSD type <i>`xsd:boolean`</i>.
1119
1120 The C alternative is to define an enumeration:
1121
1122 ~~~{.cpp}
1123 enum xsd__boolean { false_, true_ };
1124 ~~~
1125
1126 or by defining an enumeration in C with pseudo-scoped enumeration constants:
1127
1128 ~~~{.cpp}
1129 enum xsd__boolean { xsd__boolean__false, xsd__boolean__true };
1130 ~~~
1131
1132 The XML value space of these types is <i>`false`</i> and <i>`true`</i>, but also accepted
1133 are <i>`0`</i> and <i>`1`</i> values for <i>`false`</i> and <i>`true`</i>, respectively.
1134
1135 To prevent name clashes, `false_` and `true_` have a trailing underscore in
1136 their `enum` symbols. Trailing underscores are removed from the XML value space.
1137
1138 🔝 [Back to table of contents](#)
1139
1140 Enumerations and bitmasks {#toxsd4}
1141 -------------------------
1142
1143 Enumerations are mapped to XSD simpleType enumeration restrictions of
1144 <i>`xsd:string`</i>, <i>`xsd:QName`</i>, and <i>`xsd:long`</i>.
1145
1146 Consider for example:
1147
1148 ~~~{.cpp}
1149 enum ns__Color { RED, WHITE, BLUE };
1150 ~~~
1151
1152 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1153 schema:
1154
1155 <div class="alt">
1156 ~~~{.xml}
1157 <simpleType name="Color">
1158 <restriction base="xsd:string">
1159 <enumeration value="RED"/>
1160 <enumeration value="WHITE"/>
1161 <enumeration value="BLUE"/>
1162 </restriction>
1163 </simpleType>
1164 ~~~
1165 </div>
1166
1167 Enumeration name constants can be pseudo-scoped to prevent name clashes,
1168 because enumeration name constants have a global scope in C and C++:
1169
1170 ~~~{.cpp}
1171 enum ns__Color { ns__Color__RED, ns__Color__WHITE, ns__Color__BLUE };
1172 ~~~
1173
1174 You can also use C++11 scoped enumerations to prevent name clashes:
1175
1176 ~~~{.cpp}
1177 enum class ns__Color : int { RED, WHITE, BLUE };
1178 ~~~
1179
1180 Here, the enumeration class base type `: int` is optional. In place of `int`
1181 in the example above, we can also use `int8_t`, `int16_t`, `int32_t`, or
1182 `int64_t`.
1183
1184 The XML value space of the enumertions defined above is <i>`RED`</i>, <i>`WHITE`</i>, and
1185 <i>`BLUE`</i>.
1186
1187 Prefix-qualified enumeration name constants are mapped to simpleType
1188 restrictions of <i>`xsd:QName`</i>, for example:
1189
1190 ~~~{.cpp}
1191 enum ns__types { xsd__int, xsd__float };
1192 ~~~
1193
1194 which maps to a simpleType restriction of <i>`xsd:QName`</i> in the soapcpp2-generated
1195 schema:
1196
1197 <div class="alt">
1198 ~~~{.xml}
1199 <simpleType name="types">
1200 <restriction base="xsd:QName">
1201 <enumeration value="xsd:int"/>
1202 <enumeration value="xsd:float"/>
1203 </restriction>
1204 </simpleType>
1205 ~~~
1206 </div>
1207
1208 Enumeration name constants can be pseudo-numeric as follows:
1209
1210 ~~~{.cpp}
1211 enum ns__Primes { _3 = 3, _5 = 5, _7 = 7, _11 = 11 };
1212 ~~~
1213
1214 which maps to a simpleType restriction of <i>`xsd:long`</i>:
1215
1216 <div class="alt">
1217 ~~~{.xml}
1218 <simpleType name="Color">
1219 <restriction base="xsd:long">
1220 <enumeration value="3"/>
1221 <enumeration value="5"/>
1222 <enumeration value="7"/>
1223 <enumeration value="11"/>
1224 </restriction>
1225 </simpleType>
1226 ~~~
1227 </div>
1228
1229 The XML value space of this type is <i>`3`</i>, <i>`5`</i>, <i>`7`</i>, and <i>`11`</i>.
1230
1231 Besides (pseudo-) scoped enumerations, another way to prevent name clashes
1232 accross enumerations is to start an enumeration name constant with one
1233 underscore or followed it by any number of underscores, which makes it
1234 unique. The leading and trailing underscores are removed from the XML value
1235 space.
1236
1237 ~~~{.cpp}
1238 enum ns__ABC { A, B, C };
1239 enum ns__BA { B, A }; // BAD: B = 1 but B is already defined as 2
1240 enum ns__BA_ { B_, A_ }; // OK
1241 ~~~
1242
1243 The gSOAP soapcpp2 tool permits reusing enumeration name constants across
1244 (non-scoped) enumerations as long as these values are assigned the same
1245 constant. Therefore, the following is permitted:
1246
1247 ~~~{.cpp}
1248 enum ns__Primes { _3 = 3, _5 = 5, _7 = 7, _11 = 11 };
1249 enum ns__Throws { _1 = 1, _2 = 2, _3 = 3, _4 = 4, _5 = 5, _6 = 6 };
1250 ~~~
1251
1252 A bitmask type is an `enum*` "product enumeration" with a geometric,
1253 power-of-two sequence of values assigned to the enumeration constants:
1254
1255 ~~~{.cpp}
1256 enum* ns__Options { SSL3, TLS10, TLS11, TLS12, TLS13 };
1257 ~~~
1258
1259 where the product enum assigns 1 to `SSL3`, 2 to `TLS10`, 4 to `TLS11`, 8
1260 to `TLS12`, and 16 to `TLS13`, which allows these enumeration constants to be
1261 used in composing bitmasks with `|` (bitwise or) `&` (bitwise and), and `~`
1262 (bitwise not):
1263
1264 ~~~{.cpp}
1265 enum ns__Options options = (enum ns__Options)(SSL3 | TLS10 | TLS11 | TLS12 | TLS13);
1266 if (options & SSL3) // if SSL3 is an option, warn and remove from options
1267 {
1268 warning();
1269 options &= ~SSL3;
1270 }
1271 ~~~
1272
1273 The bitmask type maps to a simpleType list restriction of <i>`xsd:string`</i> in the
1274 soapcpp2-generated XML schema:
1275
1276 <div class="alt">
1277 ~~~{.xml}
1278 <simpleType name="Options">
1279 <list>
1280 <restriction base="xsd:string">
1281 <enumeration value="SSL3"/>
1282 <enumeration value="TLS10"/>
1283 <enumeration value="TLS11"/>
1284 <enumeration value="TLS12"/>
1285 <enumeration value="TLS13"/>
1286 </restriction>
1287 </list>
1288 </simpleType>
1289 ~~~
1290 </div>
1291
1292 The XML value space of this type consists of all 16 possible subsets of the
1293 four values, represented by an XML string with space-separated values. For
1294 example, the bitmask `TLS10 | TLS11 | TLS12` equals 14 and is represented by
1295 the XML text <i>`TLS10 TLS11 TLS12`</i>.
1296
1297 You can also use C++11 scoped enumerations with bitmasks using `enum*` product
1298 enumerations:
1299
1300 ~~~{.cpp}
1301 enum* class ns__Options { SSL3, TLS10, TLS11, TLS12, TLS13 };
1302 ~~~
1303
1304 The base type of a scoped enumeration bitmask, when explicitly given, is
1305 ignored. The base type is either `int` or `int64_t`, depending on the number
1306 of constants enumerated in the bitmask.
1307
1308 To convert `enum` name constants and bitmasks to a string, we use the
1309 auto-generated function for enum `T`:
1310
1311 ~~~{.cpp}
1312 const char *soap_T2s(struct soap*, enum T val)
1313 ~~~
1314
1315 The string returned is stored in an internal buffer of the current `soap`
1316 context, so you should copy it to keep it from being overwritten. For example,
1317 use `char *soap_strdup(struct soap*, const char*)`.
1318
1319 To convert a string to an `enum` constant or bitmask, we use the auto-generated
1320 function
1321
1322 ~~~{.cpp}
1323 int soap_s2T(struct soap*, const char *str, enum T *val)
1324 ~~~
1325
1326 This function takes the name (or names, space-separated for bitmasks) of
1327 the enumeration constant in a string `str`. Names should be given without the
1328 pseudo-scope prefix and without trailing underscores. The function sets `val`
1329 to the corresponding integer enum constant or to a bitmask. The function
1330 returns `SOAP_OK` (zero) on success or an error if the string is not a valid
1331 enumeration name.
1332
1333 🔝 [Back to table of contents](#)
1334
1335 Numerical types {#toxsd5}
1336 ---------------
1337
1338 Integer and floating point types are mapped to the equivalent built-in XSD
1339 types with the same sign and bit width.
1340
1341 The `size_t` type is transient (not serializable) because its width is platform
1342 dependent. We recommend to use `uint64_t` instead.
1343
1344 The XML value space of integer types are their decimal representations without
1345 loss of precision.
1346
1347 The XML value space of floating point types are their decimal representations.
1348 The decimal representations are formatted with the printf format string `"%.9G"`
1349 for floats and the printf format string `"%.17lG"` for double. To change the
1350 format strings, we can assign new strings to the following `soap` context
1351 members:
1352
1353 ~~~{.cpp}
1354 soap.float_format = "%g";
1355 soap.double_format = "%lg";
1356 soap.long_double_format = "%Lg";
1357 ~~~
1358
1359 Decimal representations may result in a loss of precision of the least
1360 significant decimal. Therefore, the format strings that are used by default
1361 are sufficiently precise to avoid loss, but this may result in long decimal
1362 fractions in the XML value space.
1363
1364 The `long double` extended floating point type requires a custom serializer:
1365
1366 ~~~{.cpp}
1367 #import "custom/long_double.h"
1368 ... // use long double
1369 ~~~
1370
1371 You can now use `long double`, which has a serializer that serializes this type
1372 as <i>`xsd:decimal`</i>. Compile and link your code with the file
1373 <i>`gsoap/custom/long_double.c`</i>.
1374
1375 The value space of floating point values includes the special values
1376 <i>`INF`</i>, <i>`-INF`</i>, and <i>`NaN`</i>. You can check a value for plus
1377 or minus infinity and not-a-number as follows:
1378
1379 ~~~{.cpp}
1380 soap_isinf(x) && x > 0 // is x INF?
1381 soap_isinf(x) && x < 0 // is x -INF?
1382 soap_isnan(x) // is x NaN?
1383 ~~~
1384
1385 To assign these values, use:
1386
1387 ~~~{.cpp}
1388 // x is float // x is double, long double, or __float128
1389 x = FLT_PINFY; x = DBL_PINFTY;
1390 x = FLT_NINFY; x = DBL_NINFTY;
1391 x = FLT_NAN; x = DBL_NAN;
1392 ~~~
1393
1394 If your system supports `__float128` then you can also use this 128 bit
1395 floating point type with a custom serializer:
1396
1397 ~~~{.cpp}
1398 #import "custom/float128.h"
1399 ... // use xsd__decimal
1400 ~~~
1401
1402 Then use the `xsd__decimal` alias of `__float128`, which has a serializer. Do
1403 not use `__float128` directly, which is transient (not serializable).
1404
1405 To check for <i>`INF`</i>, <i>`-INF`</i>, and <i>`NaN`</i> of a `__float128`
1406 value use:
1407
1408 ~~~{.cpp}
1409 isinfq(x) && x > 0 // is x INF?
1410 isinfq(x) && x < 0 // is x -INF?
1411 isnanq(x) // is x NaN?
1412 ~~~
1413
1414 The range of a `typedef`-defined numerical type can be restricted using the range
1415 `:` operator with inclusive lower and upper bounds. For example:
1416
1417 ~~~{.cpp}
1418 typedef int ns__narrow -10 : 10;
1419 ~~~
1420
1421 This maps to a simpleType restriction of <i>`xsd:int`</i> in the soapcpp2-generated
1422 schema:
1423
1424 <div class="alt">
1425 ~~~{.xml}
1426 <simpleType name="narrow">
1427 <restriction base="xsd:int">
1428 <minInclusive value="-10"/>
1429 <maxInclusive value="10"/>
1430 </restriction>
1431 </simpleType>
1432 ~~~
1433 </div>
1434
1435 The lower and upper bound of a range are optional. When omitted, values are
1436 not bound from below or from above, respectively.
1437
1438 The range of a floating point `typedef`-defined type can be restricted within
1439 floating point constant bounds.
1440
1441 Also with a floating point `typedef` a `printf`-format pattern can be given of the
1442 form `"%[width][.precision]f"` to format decimal values using the given width
1443 and precision fields:
1444
1445 ~~~{.cpp}
1446 typedef float ns__PH "%5.2f" 0.0 : 14.0;
1447 ~~~
1448
1449 This maps to a simpleType restriction of <i>`xsd:float`</i> in the soapcpp2-generated
1450 schema:
1451
1452 <div class="alt">
1453 ~~~{.xml}
1454 <simpleType name="PH">
1455 <restriction base="xsd:float">
1456 <totalDigits value="5"/>
1457 <fractionDigits value="2"/>
1458 <minInclusive value="0"/>
1459 <maxInclusive value="14"/>
1460 </restriction>
1461 </simpleType>
1462 ~~~
1463 </div>
1464
1465 For exclusive bounds, we use the `<` operator instead of the `:` range
1466 operator:
1467
1468 ~~~{.cpp}
1469 typedef float ns__epsilon 0.0 < 1.0;
1470 ~~~
1471
1472 Values `eps` of `ns__epsilon` are restricted between `0.0 < eps < 1.0`.
1473
1474 This maps to a simpleType restriction of <i>`xsd:float`</i> in the soapcpp2-generated
1475 schema:
1476
1477 <div class="alt">
1478 ~~~{.xml}
1479 <simpleType name="epsilon">
1480 <restriction base="xsd:float">
1481 <minExclusive value="0"/>
1482 <maxExclusive value="1"/>
1483 </restriction>
1484 </simpleType>
1485 ~~~
1486 </div>
1487
1488 To make just one of the bounds exclusive, while keeping the other bound
1489 inclusive, we add a `<` on the left or on the right side of the range ':'
1490 operator. For example:
1491
1492 ~~~{.cpp}
1493 typedef float ns__pos 0.0 < : ; // 0.0 < pos
1494 typedef float ns__neg : < 0.0 ; // neg < 0.0
1495 ~~~
1496
1497 It is valid to make both left and right side exclusive with `< : <` which is in
1498 fact identical to the exlusive range `<` operator:
1499
1500 ~~~{.cpp}
1501 typedef float ns__epsilon 0.0 < : < 1.0; // 0.0 < eps < 1.0
1502 ~~~
1503
1504 It helps to think of the `:` as a placeholder of the value between the two
1505 bounds, which is easier to memorize than the shorthand forms of bounds from
1506 which the `:` is removed:
1507
1508 | bounds | validation check | shorthand |
1509 | ------------ | ---------------- | ----------- |
1510 | `1 : ` | 1 <= x | `1 ` |
1511 | `1 : 10 ` | 1 <= x <= 10 | |
1512 | ` : 10 ` | x <= 10 | |
1513 | `1 < : < 10` | 1 < x < 10 | `1 < 10 ` |
1514 | `1 : < 10` | 1 <= x < 10 | |
1515 | ` : < 10` | x < 10 | ` < 10 ` |
1516 | `1 < : ` | 1 < x | `1 < ` |
1517 | `1 < : 10 ` | 1 < x <= 10 | |
1518
1519 Besides `float`, also `double` and `long double` values can be restricted. For
1520 example, consider a nonzero probability extended floating point precision type:
1521
1522 ~~~{.cpp}
1523 #import "custom/long_double.h"
1524 typedef long double ns__probability "%16Lg" 0.0 < : 1.0;
1525 ~~~
1526
1527 Value range restrictions are validated by the parser for all inbound XML data.
1528 A type fault `SOAP_TYPE` will be thrown by the deserializer if the value is out
1529 of range.
1530
1531 Finally, if your system supports `__int128_t` then you can also use this 128
1532 bit integer type with a custom serializer:
1533
1534 ~~~{.cpp}
1535 #import "custom/int128.h"
1536 ... // use xsd__integer
1537 ~~~
1538
1539 Use the `xsd__integer` alias of `__int128_t`, which has a serializer. Do not
1540 use `__int128_t` directly, which is transient (not serializable).
1541
1542 To convert numeric values to a string, we use the auto-generated function for
1543 numeric type `T`:
1544
1545 ~~~{.cpp}
1546 const char *soap_T2s(struct soap*, T val)
1547 ~~~
1548
1549 For numeric types `T`, the string returned is stored in an internal buffer of
1550 the current `soap` context, so you should copy it to keep it from being
1551 overwritten. For example, use `char *soap_strdup(struct soap*, const char*)`.
1552
1553 To convert a string to a numeric value, we use the auto-generated function
1554
1555 ~~~{.cpp}
1556 int soap_s2T(struct soap*, const char *str, T *val)
1557 ~~~
1558
1559 where `T` is for example `int`, `LONG64`, `float`, `decimal` (the custom
1560 serializer name of `long double`) or `xsd__integer` (the custom serializer name
1561 of `__int128_t`). The function `soap_s2T` returns `SOAP_OK` on success or an
1562 error when the value is not numeric. For floating point types, `"INF"`, `"-INF"`
1563 and `"NaN"` are valid strings to convert to numbers.
1564
1565 🔝 [Back to table of contents](#)
1566
1567 String types {#toxsd6}
1568 ------------
1569
1570 String types are mapped to the built-in <i>`xsd:string`</i> and <i>`xsd:QName`</i> XSD types.
1571
1572 The wide strings `wchar_t*` and `std::wstring` may contain Unicode that is
1573 preserved in the XML value space.
1574
1575 Strings `char*` and `std::string` can only contain extended Latin, but we can
1576 store UTF-8 content that is preserved in the XML value space when the `soap`
1577 context is initialized with the flag `SOAP_C_UTFSTRING`.
1578
1579 @warning Beware that many XML 1.0 parsers reject all control characters (those
1580 between `#x1` and `#x1F`) except for `#x9`, `#xA`, and `#xD`. With the
1581 newer XML 1.1 version parsers (including gSOAP) you should be fine.
1582
1583 The length of a string of a `typedef`-defined string type can be restricted:
1584
1585 ~~~{.cpp}
1586 typedef std::string ns__password 6 : 16;
1587 ~~~
1588
1589 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1590 schema:
1591
1592 <div class="alt">
1593 ~~~{.xml}
1594 <simpleType name="password">
1595 <restriction base="xsd:string">
1596 <minLength value="6"/>
1597 <maxLength value="16"/>
1598 </restriction>
1599 </simpleType>
1600 ~~~
1601 </div>
1602
1603 String length restrictions are validated by the parser for inbound XML data.
1604 A value length fault `SOAP_LENGTH` will be thrown by the deserializer if the
1605 string is too long or too short.
1606
1607 In addition, an XSD regex pattern restriction can be associated with a string
1608 typedef:
1609
1610 ~~~{.cpp}
1611 typedef std::string ns__password "([a-zA-Z]|[0-9]|-)+" 6 : 16;
1612 ~~~
1613
1614 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1615 schema:
1616
1617 <div class="alt">
1618 ~~~{.xml}
1619 <simpleType name="password">
1620 <restriction base="xsd:string">
1621 <pattern value="([a-zA-Z0-9]|-)+"/>
1622 <minLength value="6"/>
1623 <maxLength value="16"/>
1624 </restriction>
1625 </simpleType>
1626 ~~~
1627 </div>
1628
1629 Pattern restrictions are validated by the parser for inbound XML data only if
1630 the `soap::fsvalidate` and `soap::fwvalidate` callbacks are defined.
1631
1632 Exclusive length bounds can be used with strings:
1633
1634 ~~~{.cpp}
1635 typedef std::string ns__string255 : < 256; // same as 0 : 255
1636 ~~~
1637
1638 Fixed-size strings (`char[N]`) are rare occurrences in the wild, but apparently
1639 still used in some projects to store strings. To facilitate fixed-size string
1640 serialization, use <b>`soapcpp2 -b`</b> option <b>`-b`</b>. For example:
1641
1642 ~~~{.cpp}
1643 typedef char ns__buffer[10]; // requires soapcpp2 option -b
1644 ~~~
1645
1646 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1647 schema:
1648
1649 <div class="alt">
1650 ~~~{.xml}
1651 <simpleType name="buffer">
1652 <restriction base="xsd:string">
1653 <maxLength value="9"/>
1654 </restriction>
1655 </simpleType>
1656 ~~~
1657 </div>
1658
1659 Fixed-size strings must contain NUL-terminated text and should not contain raw
1660 binary data. Also, the length limitation is more restrictive for UTF-8 content
1661 (enabled with the `SOAP_C_UTFSTRING`) that requires multibyte character
1662 encodings. As a consequence, UTF-8 content may be truncated to fit.
1663
1664 Raw binary data can be stored in a `xsd__base64Binary` or `xsd__hexBinary`
1665 structure, or transmitted as a MIME attachment.
1666
1667 The built-in `_QName` type is a regular C string type (`char*`) that maps to
1668 <i>`xsd:QName`</i> but has the added advantage that it holds normalized qualified names.
1669 There are actually two forms of normalized QName content, to ensure any QName
1670 is represented accurately:
1671
1672 ~~~{.cpp}
1673 "prefix:name"
1674 "\"URI\":name"
1675 ~~~
1676
1677 The first form of string is used when the prefix (and the binding URI) is
1678 defined in the namespace table and is bound to a URI (see the .nsmap file).
1679 The second form is used when the URI is not defined in the namespace table and
1680 therefore no prefix is available to bind and normalize the URI to.
1681
1682 A `_QName` string may contain a sequence of space-separated QName values, not
1683 just one, and all QName values are normalized to the format shown above.
1684
1685 To define a `std::string` base type for <i>`xsd:QName`</i>, we use a `typedef`:
1686
1687 ~~~{.cpp}
1688 typedef std::string xsd__QName;
1689 ~~~
1690
1691 The `xsd__QName` string content is normalized, just as with the `_QName`
1692 normalization.
1693
1694 To serialize strings that contain literal XML content to be reproduced in the
1695 XML value space, use the built-in `_XML` string type, which is a regular C
1696 string type (`char*`) that maps to plain XML CDATA.
1697
1698 To define a `std::string` base type for literal XML content, use a `typedef`:
1699
1700 ~~~{.cpp}
1701 typedef std::string XML;
1702 ~~~
1703
1704 Strings can hold any of the values of the XSD built-in primitive types. We can
1705 use a string `typedef` to declare the use of the string type as a XSD built-in
1706 type:
1707
1708 ~~~{.cpp}
1709 typedef std::string xsd__token;
1710 ~~~
1711
1712 You must ensure that the string values we populate in this type conform to the
1713 XML standard, which in case of <i>`xsd:token`</i> is the lexical and value spaces of
1714 <i>`xsd:token`</i> are the sets of all strings after whitespace replacement of any
1715 occurrence of `#x9`, `#xA` , and `#xD` by `#x20` and collapsing.
1716
1717 As of version 2.8.49, the gSOAP parser will automatically collapse or replace
1718 the white space content when receiving data for XSD types that require white
1719 space collapsed or replaced. This normalization is applied to strings
1720 directly. The decision to collapse or replace is based on the `typedef` name
1721 corresponding to the built-in string-based XSD type.
1722
1723 To copy `char*` or `wchar_t*` strings with a context that manages the allocated
1724 memory, use functions
1725
1726 ~~~{.cpp}
1727 char *soap_strdup(struct soap*, const char*)
1728 wchar_t *soap_wstrdup(struct soap*, const wchar_t*)
1729 ~~~
1730
1731 To convert a wide string to a UTF-8 encoded string, use function
1732
1733 ~~~{.cpp}
1734 const char* SOAP_FMAC2 soap_wchar2s(struct soap*, const wchar_t *s)
1735 ~~~
1736
1737 The function allocates and returns a string, with its memory being managed by
1738 the context.
1739
1740 To convert a UTF-8 encoded string to a wide string, use function
1741
1742 ~~~{.cpp}
1743 int soap_s2wchar(struct soap*, const char *from, wchar_t **to, long minlen, long maxlen)
1744 ~~~
1745
1746 where `to` is set to point to an allocated `wchar_t*` string. Pass `-1` for
1747 `minlen` and `maxlen` to ignore length constraints on the target string. The
1748 function returns `SOAP_OK` or an error when the length constraints are not met.
1749
1750 🔝 [Back to table of contents](#)
1751
1752 Date and time types {#toxsd7}
1753 -------------------
1754
1755 The C/C++ `time_t` type is mapped to the built-in <i>`xsd:dateTime`</i> XSD type that
1756 represents a date and time within a time zone (typically UTC).
1757
1758 The XML value space contains ISO 8601 Gregorian time instances of the form
1759 <i>`[-]CCYY-MM-DDThh:mm:ss.sss[Z|(+|-)hh:mm]`</i>, where <i>`Z`</i> is the UTC time zone
1760 or a time zone offset <i>`(+|-)hh:mm]`</i> from UTC is used.
1761
1762 A `time_t` value is considered and represented in UTC by the serializer.
1763
1764 Because the `time_t` value range is restricted to dates after 01/01/1970 and
1765 before 2038 assuming `time_t` is a `long` 32 bit, care must be taken to ensure
1766 the range of <i>`xsd:dateTime`</i> values in XML exchanges do not exceed the `time_t`
1767 range.
1768
1769 This restriction does not hold for `struct tm` (<i>`time.h`</i> library), which we can use
1770 to store and exchange a date and time in UTC without date range restrictions.
1771 The serializer uses the `struct tm` members directly for the XML value space of
1772 <i>`xsd:dateTime`</i>:
1773
1774 ~~~{.cpp}
1775 struct tm
1776 {
1777 int tm_sec; // seconds (0 - 60)
1778 int tm_min; // minutes (0 - 59)
1779 int tm_hour; // hours (0 - 23)
1780 int tm_mday; // day of month (1 - 31)
1781 int tm_mon; // month of year (0 - 11)
1782 int tm_year; // year - 1900
1783 int tm_wday; // day of week (Sunday = 0) (NOT USED)
1784 int tm_yday; // day of year (0 - 365) (NOT USED)
1785 int tm_isdst; // is summer time in effect?
1786 char* tm_zone; // abbreviation of timezone (NOT USED)
1787 };
1788 ~~~
1789
1790 You will lose the day of the week information. It is always Sunday
1791 (`tm_wday=0`) and the day of the year is not set either. The time zone is UTC.
1792
1793 This `struct tm` type is mapped to the built-in <i>`xsd:dateTime`</i> XSD type and
1794 serialized with the custom serializer <i>`gsoap/custom/struct_tm.h`</i> that declares a
1795 `xsd__dateTime` type:
1796
1797 ~~~{.cpp}
1798 #import "custom/struct_tm.h" // import typedef struct tm xsd__dateTime;
1799 ... // use xsd__dateTime
1800 ~~~
1801
1802 Compile and link your code with <i>`gsoap/custom/struct_tm.c`</i>.
1803
1804 The `struct timeval` (<i>`sys/time.h`</i> library) type is mapped to the
1805 built-in <i>`xsd:dateTime`</i> XSD type and serialized with the custom serializer
1806 <i>`gsoap/custom/struct_timeval.h`</i> that declares a `xsd__dateTime` type:
1807
1808 ~~~{.cpp}
1809 #import "custom/struct_timeval.h" // import typedef struct timeval xsd__dateTime;
1810 ... // use xsd__dateTime
1811 ~~~
1812
1813 Compile and link your code with <i>`gsoap/custom/struct_timeval.c`</i>.
1814
1815 The same value range restrictions apply to `struct timeval` as they apply to
1816 `time_t`. The added benefit of `struct timeval` is the addition of a
1817 microsecond-precise clock:
1818
1819 ~~~{.cpp}
1820 struct timeval
1821 {
1822 time_t tv_sec; // seconds since Jan. 1, 1970
1823 suseconds_t tv_usec; // and microseconds
1824 };
1825 ~~~
1826
1827 A C++11 `std::chrono::system_clock::time_point` type is mapped to the built-in
1828 <i>`xsd:dateTime`</i> XSD type and serialized with the custom serializer
1829 <i>`gsoap/custom/chrono_time_point.h`</i> that declares a `xsd__dateTime` type:
1830
1831 ~~~{.cpp}
1832 #import "custom/chrono_time_point.h" // import typedef std::chrono::system_clock::time_point xsd__dateTime;
1833 ... // use xsd__dateTime
1834 ~~~
1835
1836 Compile and link your code with <i>`gsoap/custom/chrono_time_point.cpp`</i>.
1837
1838 The `struct tm` type is mapped to the built-in <i>`xsd:date`</i> XSD type and serialized
1839 with the custom serializer <i>`gsoap/custom/struct_tm_date.h`</i> that declares a
1840 `xsd__date` type:
1841
1842 ~~~{.cpp}
1843 #import "custom/struct_tm_date.h" // import typedef struct tm xsd__date;
1844 ... // use xsd__date
1845 ~~~
1846
1847 Compile and link your code with <i>`gsoap/custom/struct_tm_date.c`</i>.
1848
1849 The XML value space of <i>`xsd:date`</i> are Gregorian calendar dates of the form
1850 <i>`[-]CCYY-MM-DD[Z|(+|-)hh:mm]`</i> with a time zone.
1851
1852 The serializer ignores the time part and the deserializer only populates the
1853 date part of the struct, setting the time to 00:00:00. There is no unreasonable
1854 limit on the date range because the year field is stored as an integer (`int`).
1855
1856 An `unsigned long long` (`ULONG64` or `uint64_t`) type that contains a 24 hour
1857 time in microseconds UTC is mapped to the built-in <i>`xsd:time`</i> XSD type and
1858 serialized with the custom serializer <i>`gsoap/custom/long_time.h`</i> that declares a
1859 `xsd__time` type:
1860
1861 ~~~{.cpp}
1862 #import "custom/long_time.h" // import typedef unsigned long long xsd__time;
1863 ... // use xsd__time
1864 ~~~
1865
1866 Compile and link your code with <i>`gsoap/custom/long_time.c`</i>.
1867
1868 This type represents `00:00:00.000000` to `23:59:59.999999`, from 0 to an
1869 upper bound of 86,399,999,999. A microsecond resolution means that a 1 second
1870 increment requires an increment of 1,000,000 in the integer value.
1871
1872 The XML value space of <i>`xsd:time`</i> are points in time recurring each day of the
1873 form <i>`hh:mm:ss.sss[Z|(+|-)hh:mm]`</i>, where <i>`Z`</i> is the UTC time zone or a time
1874 zone offset from UTC is used. The `xsd__time` value is always considered and
1875 represented in UTC by the serializer.
1876
1877 To convert date and/or time values to a string, we use the auto-generated
1878 function for type `T`:
1879
1880 ~~~{.cpp}
1881 const char *soap_T2s(struct soap*, T val)
1882 ~~~
1883
1884 For date and time types `T`, the string returned is stored in an internal
1885 buffer of the current `soap` context, so you should copy it to keep it from being
1886 overwritten. For example, use `char *soap_strdup(struct soap*, const char*)`.
1887
1888 To convert a string to a date/time value, we use the auto-generated function
1889
1890 ~~~{.cpp}
1891 int soap_s2T(struct soap*, const char *str, T *val)
1892 ~~~
1893
1894 where `T` is for example `dateTime` (for `time_t`), `xsd__dateTime` (for
1895 `struct tm`, `struct timeval`, or `std::chrono::system_clock::time_point`).
1896 The function `soap_s2T` returns `SOAP_OK` on success or an error when the value
1897 is not a date/time.
1898
1899 🔝 [Back to table of contents](#)
1900
1901 Time duration types {#toxsd8}
1902 -------------------
1903
1904 The XML value space of <i>`xsd:duration`</i> are values of the form <i>`PnYnMnDTnHnMnS`</i>
1905 where the capital letters are delimiters. Delimiters may be omitted when the
1906 corresponding member is not used.
1907
1908 A `long long` (`LONG64` or `int64_t`) type that contains a duration (time
1909 lapse) in milliseconds is mapped to the built-in <i>`xsd:duration`</i> XSD type and
1910 serialized with the custom serializer <i>`gsoap/custom/duration.h`</i> that declares a
1911 `xsd__duration` type:
1912
1913 ~~~{.cpp}
1914 #import "custom/duration.h" // import typedef long long xsd__duration;
1915 ... // use xsd__duration
1916 ~~~
1917
1918 Compile and link your code with <i>`gsoap/custom/duration.c`</i>.
1919
1920 The duration type `xsd__duration` can represent 106,751,991,167 days forward
1921 and backward with millisecond precision.
1922
1923 Durations that exceed a month are always output in days, rather than months to
1924 avoid days-per-month conversion inacurracies.
1925
1926 Durations that are received in years and months instead of total number of days
1927 from a reference point are not well defined, since there is no accepted
1928 reference time point (it may or may not be the current time). The decoder
1929 simple assumes that there are 30 days per month. For example, conversion of
1930 "P4M" gives 120 days. Therefore, the durations "P4M" and "P120D" are assumed
1931 to be identical, which is not necessarily true depending on the reference point
1932 in time.
1933
1934 Rescaling of the duration value by may be needed when adding the duration value
1935 to a `time_t` value, because `time_t` may or may not have a seconds resolution,
1936 depending on the platform and possible changes to `time_t`.
1937
1938 Rescaling is done automatically when you add a C++11 `std::chrono::nanoseconds`
1939 value to a `std::chrono::system_clock::time_point` value. To use
1940 `std::chrono::nanoseconds` as <i>`xsd:duration`</i>:
1941
1942 ~~~{.cpp}
1943 #import "custom/chrono_duration.h" // import typedef std::chrono::duration xsd__duration;
1944 ... // use xsd__duration
1945 ~~~
1946
1947 Compile and link your code with <i>`gsoap/custom/chrono_duration.cpp`</i>.
1948
1949 This type can represent 384,307,168 days (2^63 nanoseconds) forwards and
1950 backwards in time in increments of 1 ns (1/1000000000 second).
1951
1952 The same observations with respect to receiving durations in years and months
1953 apply to this serializer's decoder.
1954
1955 To convert duration values to a string, we use the auto-generated function
1956
1957 ~~~{.cpp}
1958 const char *soap_xsd__duration2s(struct soap*, xsd__duration val)
1959 ~~~
1960
1961 The string returned is stored in an internal buffer, so you should copy it to
1962 keep it from being overwritten, Use `soap_strdup(struct soap*, const char*)`
1963 for example to copy this string.
1964
1965 To convert a string to a duration value, we use the auto-generated function
1966
1967 ~~~{.cpp}
1968 int soap_s2xsd__dateTime(struct soap*, const char *str, xsd__dateTime *val)
1969 ~~~
1970
1971 The function returns `SOAP_OK` on success or an error when the value is not a
1972 duration.
1973
1974 🔝 [Back to table of contents](#)
1975
1976 Classes and structs {#toxsd9}
1977 -------------------
1978
1979 Classes and structs are mapped to XSD complexTypes. The XML value space
1980 consists of XML elements with attributes and subelements, possibly constrained
1981 by XML schema validation rules that enforce element and attribute occurrence
1982 contraints, numerical value range constraints, and string length and pattern
1983 constraints.
1984
1985 Classes that are declared with the gSOAP tools are limited to single
1986 inheritence only. The soapcpp2 tool does not allow structs to be inherited.
1987
1988 The class and struct name is bound to an XML namespace by means of the prefix
1989 naming convention or by using [colon notation](#toxsd1):
1990
1991 ~~~{.cpp}
1992 //gsoap ns schema namespace: urn:types
1993 class ns__record
1994 {
1995 public:
1996 std::string name;
1997 uint64_t SSN;
1998 ns__record *spouse;
1999 ns__record();
2000 ~ns__record();
2001 protected:
2002 struct soap *soap;
2003 };
2004 ~~~
2005
2006 In the example above, we also added a context pointer to the `soap` context that
2007 manages this instance. It is set when the instance is created in the engine's
2008 context, for example when deserialized and populated by the engine.
2009
2010 The class maps to a complexType in the soapcpp2-generated XML schema:
2011
2012 <div class="alt">
2013 ~~~{.xml}
2014 <complexType name="record">
2015 <sequence>
2016 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
2017 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
2018 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" nillable="true"/>
2019 </sequence>
2020 </complexType>
2021 ~~~
2022 </div>
2023
2024 The following sections apply to both structs and classes. Structs require the
2025 use of the `struct` keyword with the struct name, otherwise soapcpp2 will throw
2026 a syntax error. As is often done in C, use a `typedef` to declare a `struct`
2027 that can be used without the `struct` keyword.
2028
2029 🔝 [Back to table of contents](#)
2030
2031 ### Serializable versus transient types and data members {#toxsd9-1}
2032
2033 Public data members of a class or struct are serializable when their types are
2034 serializable. Private and protected members are transient and not
2035 serializable.
2036
2037 Also `const` and `static` members are not serializable, with the exception of
2038 `const char*` and `const wchar_t*`. Types and specific class/struct members
2039 can be made transient with the `extern` qualifier for types and by marking
2040 members with `[` and `]`:
2041
2042 ~~~{.cpp}
2043 extern class std::ostream; // declare std::ostream transient
2044 class ns__record
2045 {
2046 public:
2047 [ int num; ] // not serialized: member is marked transient with [ ]
2048 std::ostream out; // not serialized: std:ostream is transient
2049 static const int MAX = 1024; // not serialized: static const member
2050 private:
2051 std::string id; // not serialized: private member
2052 };
2053 ~~~
2054
2055 By declaring `std::ostream` transient with `extern` you can use this type
2056 wherever you need it without soapcpp2 complaining that this class and any other
2057 class or type declared as `extern` is not defined. Do not use `extern` with
2058 `typedef`, because this declares a custom serializer, see
2059 [adding custom serializers](#custom).
2060
2061 Marking members transient with `[` and `]` makes them transient (and visually
2062 makes them stand out). This has otherwise no effect on the generated code for
2063 the class or struct to be used in your application code.
2064
2065 🔝 [Back to table of contents](#)
2066
2067 ### Derived types in C++ {#toxsd9-1-1}
2068
2069 Extensible and restricted types in XML schemas are derived types from single
2070 simple and complex base types. XML schema derived types are naturally
2071 represented by C++ derived classes using single inheritance. Besides the
2072 concept of extensions versus restrictions, there are two kinds of derived
2073 types: complexTypes with simpleContent, meaning types with XML CDATA values,
2074 and complexTypes with complexContent, meaning types with sub-elements. Both
2075 are permitted to have one or more XML attributes.
2076
2077 A complexType with simpleContent is defined as a wrapper to contain XML CDATA
2078 values and any number of attributes, see
2079 [wrapper class/struct with simpleContent](#toxsd10-4).
2080 Wrapper class/struct types can form a hierarchy of derived types in C++ using
2081 inheritance. For example:
2082
2083 ~~~{.cpp}
2084 class xsd__anyType
2085 {
2086 public:
2087 std::string __item; // string to hold any simpleContent
2088 };
2089 class ns__data : public xsd__anyType
2090 {
2091 public:
2092 @ std::string value 1; // extends xsd:anyType with a required attribute
2093 };
2094 ~~~
2095
2096 The `ns__data` class maps to a complexType in the soapcpp2-generated XML schema:
2097
2098 <div class="alt">
2099 ~~~{.xml}
2100 <complexType name="string">
2101 <simpleContent>
2102 <extension base="xsd:string">
2103 <attribute name="value" type="xsd:string" use="required"/>
2104 </extension>
2105 </simpleContent>
2106 </complexType>
2107 ~~~
2108 </div>
2109
2110 The XML value space consists of an element with the string contents an optional
2111 attribute:
2112
2113 <div class="alt">
2114 ~~~{.xml}
2115 <ns:data value="abc">xyz</ns:data>
2116 ~~~
2117 </div>
2118
2119 By contrast, a complexType with complexContent typically extends a given base
2120 complexType. For example:
2121
2122 ~~~{.cpp}
2123 class ns__base
2124 {
2125 public:
2126 std::string name 1;
2127 int number 1;
2128 };
2129 class ns__derived : public ns__base
2130 {
2131 public:
2132 @ std::string value 1; // extends ns:base with an attribute
2133 std::string text 1; // extends ns:base with an element
2134 };
2135 ~~~
2136
2137 The `ns__base` and `ns__derived` classes maps to complexTypes in the soapcpp2-generated XML schema:
2138
2139 <div class="alt">
2140 ~~~{.xml}
2141 <complexType name="base">
2142 <sequence>
2143 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
2144 <element name="number" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2145 </sequence>
2146 </complexType>
2147 <complexType name="derived">
2148 <complexContent>
2149 <extension base="ns:base">
2150 <sequence>
2151 <element name="text" type="xsd:string" minOccurs="1" maxOccurs="1"/>
2152 </sequence>
2153 </extension>
2154 </complexContent>
2155 <attribute name="value" type="xsd:string" use="required"/>
2156 </complexType>
2157 ~~~
2158 </div>
2159
2160 The XML value space of `ns__derived` consists of three requires child elements
2161 and an optional attribute:
2162
2163 <div class="alt">
2164 ~~~{.xml}
2165 <ns:derived value="abc">
2166 <name>def</name>
2167 <number>123</number>
2168 <text>xyz</text>
2169 </ns:derived>
2170 ~~~
2171 </div>
2172
2173 Derived types can be used for two main purposes in XML schema by extending or
2174 restricting base types. One purpose is to reuse a base type when defining a
2175 derived type, such that common parts do not need to be replicated. The second
2176 purpose is to be able to use a derived type in place of a base type in XML, which
2177 is indicated by an <i>`xsi:type`</i> attribute with the qualified name of the
2178 derived type. Consider for example the following class that uses the
2179 previously declared base types `xsd__anyType` and `ns__base`:
2180
2181 ~~~{.cpp}
2182 class ns__record
2183 {
2184 public:
2185 xsd__anyType *base1 1; // required element
2186 ns__base *base2 1; // required element
2187 };
2188 ~~~
2189
2190 We can assign base type values to the `ns_record` members:
2191
2192 ~~~{.cpp}
2193 ns__record record;
2194 record.base1 = soap_new_xsd__anyType(soap);
2195 record.base2 = soap_new_ns__base(soap);
2196 soap_write_ns__record(soap, &record);
2197 ~~~
2198
2199 This produces the following XML fragment populated with default values (empty
2200 text for strings and zeros for numbers), where element <i>`base1`</i> has a
2201 simpleContent value and element <i>`base2`</i> has two child elements:
2202
2203 <div class="alt">
2204 ~~~{.xml}
2205 <ns:record>
2206 <base1></base1>
2207 <base2>
2208 <name></name>
2209 <number>0</number>
2210 </base2>
2211 </ns:record>
2212 ~~~
2213 </div>
2214
2215 We can also assign derived type values to the `ns_record` members:
2216
2217 ~~~{.cpp}
2218 ns__record record;
2219 record.base1 = soap_new_ns__data(soap);
2220 record.base2 = soap_new_ns__derived(soap);
2221 soap_write_ns__record(soap, &record);
2222 ~~~
2223
2224 This produces the following XML fragment populated with default values (empty
2225 text for strings and zeros for numbers), where element <i>`base1`</i> has
2226 schema type <i>`ns:data`</i> with simpleContent and an attribute, and
2227 <i>`base2`</i> has schema type <i>`ns:derived`</i> with three child elements
2228 and an attribute:
2229
2230 <div class="alt">
2231 ~~~{.xml}
2232 <ns:record>
2233 <base1 xsi:type="ns:data" value=""></base1>
2234 <base2 xsi:type="ns:derived" value="">
2235 <name></name>
2236 <number>0</number>
2237 <text></text>
2238 </base2>
2239 </ns:record>
2240 ~~~
2241 </div>
2242
2243 Deserialization automatically allocates and assigns a `ns__base` class instance to a
2244 `ns__base` pointer when deserializing the <i>`ns:base`</i> schema type and allocates and
2245 assigns a `ns__derived` class instance to a `ns__base` pointer when deserializing the
2246 <i>`ns:derived`</i> type when an element with <i>`xsi:type="ns:derived"`</i> is
2247 parsed. All classes are extended by soapcpp2 by a `soap_type()` method that
2248 returns the unique `SOAP_TYPE_T` value of the class `T`. This makes it easy to
2249 check whether the deserialized data contains a derived type to implement
2250 type-safe code, for example:
2251
2252 ~~~{.cpp}
2253 ns__record record;
2254 soap_read_ns__record(soap, &record);
2255 if (record.base1->soap_type() == SOAP_TYPE_ns__data)
2256 std::cout << "Derived ns:data "
2257 << dynamic_cast<ns__data*>(record.base1)->value
2258 << std::endl;
2259 else
2260 std::cout << "Base xsd:anyType" << std::endl;
2261 if (record.base2->soap_type() == SOAP_TYPE_ns__derived)
2262 std::cout << "Derived ns:derived "
2263 << dynamic_cast<ns__derived*>(record.base2)->value
2264 << std::endl;
2265 else
2266 std::cout << "Base ns:base" << std::endl;
2267 ~~~
2268
2269 This example should use the `SOAP_XML_STRICT` mode flag to initialize the
2270 `soap` context to ensure that all required values are present in the
2271 deserialized structures.
2272
2273 🔝 [Back to table of contents](#)
2274
2275 ### Derived types in C {#toxsd9-1-2}
2276
2277 While single inheritance works well in C++ to represent derived types as we
2278 discussed in the previous section, this will obviously not work in C. Two
2279 methods to serialize derived types in C are presented here. The first method
2280 uses `void*` to serialize anything. The second method is more accurate and is
2281 relatively new in gSOAP.
2282
2283 To serialize any type is possible with [tagged void pointer members](#toxsd9-12) to
2284 serialize data pointed to by a `void*` member, which can be any serializable
2285 type, such as derived types. For `void*` deserialization to work the XML
2286 parsed must contain an <i>`xsi:type`</i> attribute with a schema type. Only
2287 then can the deserializer instantiate the corresponding serializable C/C++
2288 type. Base types serialized do not require an <i>`xsi:type`</i> to indicate
2289 the base schema type, so this approach is not guaranteed to work and requires a
2290 workaround with an anonymous wrapper struct/class that contains both the base
2291 type and a `void*`. For example:
2292
2293 ~~~{.cpp}
2294 struct ns__base // a base type
2295 {
2296 char *name 1;
2297 int number 1;
2298 };
2299 struct ns__derived // extends ns__base with two additional members
2300 {
2301 char *name 1;
2302 int number 1;
2303 char *text 1;
2304 @ char *value 1;
2305 };
2306 struct __ns__base // a wrapper, not visible in XML
2307 {
2308 int __type; // the SOAP_TYPE_T pointed to by __self
2309 void *__self; // points to any type
2310 struct ns__base *__self; // wraps ns__base for the current element tag
2311 }
2312 class ns__record
2313 {
2314 struct __ns__base base;
2315 };
2316 ~~~
2317
2318 The `__ns__base` wrapper wraps the `ns__base` type to (de)serialize the
2319 <i>`base`</i> element that has no <i>`xsi:type`</i> attribute and uses `void*`
2320 to (de)serialize the <i>`base`</i> element that has <i>`xsi:type`</i>
2321 attribute. This works fine at the XML parsing level, but the generated
2322 XML schema components do not accurately represent the derived type, because it
2323 lacks the extension/restriction of the derived type (and the `__ns__base`
2324 wrapper is invisible).
2325
2326 Using `void*` to represent derived types in a base type wrapper is not very
2327 accurate because we can serialize anything, not just derived types of a given
2328 base type. The wrapper may also hold two values: the base type value and a
2329 derived type value. Furthermore, using arrays or containers that hold base and
2330 derived types becomes quite tricky because an array item could hold both the
2331 base and derived type.
2332
2333 As of gSOAP version 2.8.75, `wsdl2h -F` option `-F` generates base type structs
2334 extended with transient pointer members to its derived types. To serialize the
2335 base type itself, all of the pointer members are NULL. If one of the pointer
2336 members points to a derived type the derived type is serialized instead.
2337 Deserialization is automatic, in that the base type is deserialized if the
2338 element has no <i>`xsi:type`</i> attribute or the attribute is the base schema
2339 type, and a derived type is deserialized if the element has an
2340 <i>`xsi>type`</i> attribute with the derived schema type.
2341
2342 This method is fully automated for the wsdl2h tool to generate an interface
2343 header file for soapcpp2 with the type derivations in C. To use this method to
2344 generate code from WSDLs and XSDs, use `wsdl2h -F` option `-F`. This also
2345 works in C++ if desired, but C++ inheritance works fine without this method.
2346
2347 Using this method with soapcpp2 alone using a manually-specified interface
2348 header file produces the specified type inheritance in the soapcpp2-generated
2349 WSDL and XML schema files as complexType extensions.
2350
2351 The soapcpp2 tool warns if a derived type has multiple base types. At most one
2352 base type for a derived type may be specified.
2353
2354 This method with transient pointers to derived types makes it easy to use base
2355 and derived types in C:
2356
2357 ~~~{.cpp}
2358 struct ns__base // a base type
2359 {
2360 char *name 1;
2361 int number 1;
2362 [ struct ns__derived *ns__derived; ] // points to derived type if non-NULL
2363 };
2364 struct ns__derived // extends ns__base with two additional members
2365 {
2366 char *name 1;
2367 int number 1;
2368 char *text 1;
2369 @ char *value 1;
2370 };
2371 struct ns__record
2372 {
2373 struct ns__base base; // contains base type or derived type value
2374 };
2375 ~~~
2376
2377 The `ns__base` struct includes the special member `ns__derived` that points to
2378 a `ns__derived` value. This special member must be:
2379
2380 - a transient member (i.e. non-serializable) by placing the declaration within
2381 `[` and `]`, and
2382 - the member name must match the type name (to be more precise, at least the
2383 initial part of the member name must match the type name as in the example
2384 `ns__derived_` works too).
2385
2386 To serialize the `ns__base` value requires the `ns__derived` member to be NULL.
2387 To serialize the `ns__derived` value requires the `ns__derived` member to point
2388 to the `ns__derived` value to serialize and the `ns__base` members are
2389 irrelevant.
2390
2391 We can assign the base type value to the `ns_record::base` member:
2392
2393 ~~~{.cpp}
2394 struct ns__record record;
2395 soap_default_ns__record(soap, &record);
2396 soap_write_ns__record(soap, &record);
2397 ~~~
2398
2399 This produces the following XML fragment populated with default values (empty
2400 text for strings and zeros for numbers), where element <i>`base`</i> has two
2401 child elements:
2402
2403 <div class="alt">
2404 ~~~{.xml}
2405 <ns:record>
2406 <base>
2407 <name></name>
2408 <number>0</number>
2409 </base>
2410 </ns:record>
2411 ~~~
2412 </div>
2413
2414 We can also assign the derived type value to the `ns_record::base` member:
2415
2416 ~~~{.cpp}
2417 struct ns__record record;
2418 soap_default_ns__record(soap, &record);
2419 record.base.ns__derived = soap_new_ns__derived(soap, -1);
2420 soap_write_ns__record(soap, &record);
2421 ~~~
2422
2423 This produces the following XML fragment populated with default values (empty
2424 text for strings and zeros for numbers), where element <i>`base`</i> has schema
2425 type <i>`ns:derived`</i> with three child elements and an attribute:
2426
2427 <div class="alt">
2428 ~~~{.xml}
2429 <ns:record>
2430 <base xsi:type="ns:derived" value="">
2431 <name></name>
2432 <number>0</number>
2433 <text></text>
2434 </base>
2435 </ns:record>
2436 ~~~
2437 </div>
2438
2439 Deserialization automatically assigns values to the base members for the
2440 `ns__base` type and populates the `ns__derived` member when a derived type with
2441 <i>`xsi:type="ns:derived"`</i> is parsed. This makes it easy to decompose the
2442 deserialized data:
2443
2444 ~~~{.cpp}
2445 struct ns__record record;
2446 soap_read_ns__record(soap, &record);
2447 if (record.ns__derived)
2448 printf("Derived type with name=%s number=%d text=%s value=%s\n",
2449 record.ns__derived->name,
2450 record.ns__derived->number,
2451 record.ns__derived->text,
2452 record.ns__derived->value);
2453 else
2454 printf("Base type with name=%s number=%d\n",
2455 record.name,
2456 record.number);
2457 ~~~
2458
2459 This example requires the `SOAP_XML_STRICT` mode flag to initialize the `soap`
2460 context to ensure that all required values are present in the deserialized
2461 structures, otherwise the `char*` strings may be NULL since XML validation
2462 constraints are not enforced on the XML input.
2463
2464 Deeper levels of simulated inheritance are possible, for example:
2465
2466 ~~~{.cpp}
2467 struct ns__base // a base type
2468 {
2469 char *name 1;
2470 int number 1;
2471 [ struct ns__derived *ns__derived; ] // points to derived type if non-NULL
2472 };
2473 struct ns__derived // extends ns__base with two additional members
2474 {
2475 char *name 1;
2476 int number 1;
2477 char *text 1;
2478 @ char *value 1;
2479 [ struct ns__derived_derived *ns__derived_derived; ] // points to derived_derived type if non-NULL
2480 };
2481 struct ns__derived_derived // extends ns__derived with an additional member
2482 {
2483 char *name 1;
2484 int number 1;
2485 char *text 1;
2486 @ char *value 1;
2487 @ char *type 1;
2488 };
2489 ~~~
2490
2491 This requires two pointer traversals from the base type `ns__base` via
2492 `ns__derived` to reach `ns__derived_derived`.
2493
2494 🔝 [Back to table of contents](#)
2495
2496 ### Volatile classes and structs {#toxsd9-2}
2497
2498 Classes and structs can be declared `volatile` in the interface header file for
2499 soapcpp2, which only has meaning for the gSOAP tools. This annotation means
2500 that these types are already declared elsewhere in your project's source code
2501 and you do not want soapcpp2 to generate code with a second declaration of
2502 these types.
2503
2504 For example, `struct tm` is declared in the <i>`time.h`</i> library. You can
2505 make it serializable and include a partial list of data members that you want
2506 to serialize:
2507
2508 ~~~{.cpp}
2509 volatile struct tm
2510 {
2511 int tm_sec; // seconds (0 - 60)
2512 int tm_min; // minutes (0 - 59)
2513 int tm_hour; // hours (0 - 23)
2514 int tm_mday; // day of month (1 - 31)
2515 int tm_mon; // month of year (0 - 11)
2516 int tm_year; // year - 1900
2517 };
2518 ~~~
2519
2520 You can declare classes and structs `volatile` for any such types you want to
2521 serialize by only providing the public data members you want to serialize.
2522
2523 In addition, [colon notation](#toxsd2) is a simple and effective way to bind an
2524 existing class or struct to a schema. For example, you can change the `tm` name
2525 as follows without affecting the code that uses `struct tm` generated by
2526 soapcpp2:
2527
2528 ~~~{.cpp}
2529 volatile struct ns:tm { ... }
2530 ~~~
2531
2532 This struct maps to a complexType in the soapcpp2-generated XML schema:
2533
2534 <div class="alt">
2535 ~~~{.xml}
2536 <complexType name="tm">
2537 <sequence>
2538 <element name="tm-sec" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2539 <element name="tm-min" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2540 <element name="tm-hour" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2541 <element name="tm-mday" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2542 <element name="tm-mon" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2543 <element name="tm-year" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2544 </sequence>
2545 </complexType>
2546 ~~~
2547 </div>
2548
2549 🔝 [Back to table of contents](#)
2550
2551 ### Mutable classes and structs {#toxsd9-3}
2552
2553 Classes and structs can be declared `mutable` with the gSOAP tools. This means
2554 that their definition can be spread out over the source code. This promotes the
2555 concept of a class or struct as a *row of named values*, also known as a *named
2556 tuple*, that can be extended at compile time in your source code with additional
2557 members. Because these types differ from the traditional object-oriented
2558 principles and design concepts of classes and objects, constructors and
2559 destructors cannot be defined (also because we cannot guarantee merging these
2560 into one such that all members will be initialized). A default constructor,
2561 copy constructor, assignment operation, and destructor will be assigned
2562 automatically by soapcpp2.
2563
2564 ~~~{.cpp}
2565 mutable struct ns__tuple
2566 {
2567 @ std::string id;
2568 };
2569
2570 mutable struct ns__tuple
2571 {
2572 std::string name;
2573 std::string value;
2574 };
2575 ~~~
2576
2577 The members are collected into one definition generated by soapcpp2. Members
2578 may be repeated from one definition to another, but only if their associated
2579 types are identical. So, for example, a third extension with a `value` member
2580 with a different type fails:
2581
2582 ~~~{.cpp}
2583 mutable struct ns__tuple
2584 {
2585 float value; // BAD: value is already declared std::string
2586 };
2587 ~~~
2588
2589 The `mutable` concept has proven to be very useful when declaring and
2590 collecting SOAP Headers for multiple services, which are collected into one
2591 `struct SOAP_ENV__Header` by the soapcpp2 tool.
2592
2593 🔝 [Back to table of contents](#)
2594
2595 ### Default and fixed member values {#toxsd9-4}
2596
2597 Class and struct data members in C and C++ may be declared with an optional
2598 default initialization value that is provided "inline" with the declaration of
2599 the member:
2600
2601 ~~~{.cpp}
2602 class ns__record
2603 {
2604 public:
2605 std::string name = "Joe";
2606 ...
2607 };
2608 ~~~
2609
2610 Alternatively, you can use C++11 default initialization syntax:
2611
2612 ~~~{.cpp}
2613 class ns__record
2614 {
2615 public:
2616 std::string name { "Joe" };
2617 ...
2618 };
2619 ~~~
2620
2621 Any member with a primitive type can be initialized in this way.
2622
2623 These initializations are performed by the default constructor that is added by
2624 soapcpp2 to each class and struct (in C++ only). A constructor is only added
2625 when a default constructor is not already defined with the class declaration.
2626
2627 You can explicitly (re)initialize an object with these initial values by using
2628 the soapcpp2 auto-generated functions:
2629
2630 - `void T::soap_default(struct soap*)` for `class T` (C++ only)
2631
2632 - `void soap_default_T(struct soap*, T*)` for `struct T` (C and C++).
2633
2634 If `T` is a struct or class that has a `soap` pointer member to a `::soap`
2635 context then this pointer member will be set to the first argument passed to
2636 these functions to initialize their `soap` pointer member.
2637
2638 Default value initializations can be provided for members that have primitive
2639 types (`bool`, `enum`, `time_t`, numeric and string types).
2640
2641 Default value initializations of pointer members is permitted, but the effect
2642 is different. To conform to XML schema validation, an attribute member that is
2643 a pointer to a primitive type will be assigned the default value when parsed
2644 from XML. An element member that is a pointer to a primitive type will be
2645 assigned when the element is empty when parsed from XML.
2646
2647 As of gSOAP 2.8.48 and greater, a fixed value can be assigned with a `==`. A
2648 fixed value is also verified by the parser's validator.
2649
2650 Default and fixed values for members with or without pointers are best
2651 explained with the following two example fragments.
2652
2653 A record class with default values for `std::string` (or `std::wstring`)
2654 attributes and elements is declared as follows:
2655
2656 ~~~{.cpp}
2657 class ns__record_with_default
2658 {
2659 public:
2660 @ std::string a = "A"; // optional XML attribute with default value "A"
2661 @ std::string b 1 = "B"; // required XML attribute with default value "B"
2662 @ std::string *c = "C"; // optional XML attribute with default value "C"
2663 std::string d 0 = "D"; // optional XML element with default value "D"
2664 std::string e = "E"; // required XML element with default value "E"
2665 std::string *f = "F"; // optional XML element with default value "F"
2666 ...
2667 };
2668 ~~~
2669
2670 Also `std::unique_ptr` and `std::shared_ptr` may be used instead of a regular
2671 pointer to strings.
2672
2673 With C `char*` (or `const char*`, `const wchar_t*`) strings in a struct, this
2674 becomes:
2675
2676 ~~~{.cpp}
2677 struct ns__record_with_default
2678 {
2679 @ char* a = "A"; // optional XML attribute with default value "A"
2680 @ char* b 1 = "B"; // required XML attribute with default value "B"
2681 char* e 1 = "E"; // required XML element with default value "E"
2682 char* f = "F"; // optional XML element with default value "F"
2683 ...
2684 };
2685 ~~~
2686
2687 By contrast to `std::string e`, `char* e` must be marked `1` to make it
2688 required, because pointer members are optional by default.
2689
2690 Attributes are considered optional by default, unless marked as required with
2691 the occurrence constraint `1`. Elements are considered required unless the
2692 member type is a pointer or if the member is marked optional with occurrence
2693 constraint `0`.
2694
2695 Instead of default values, fixed values indicate that the attribute or element
2696 must contain that value, and only that value, when provided in XML. A fixed
2697 value is specified with a `==`.
2698
2699 Attributes with default or fixed values may be omitted in XML. When absent,
2700 the default/fixed value is used at the receiving side, i.e. the deserializer
2701 assigns the default/fixed value when the attribute is absent. Therefore, there
2702 is no need to make attributes with default/fixed values pointer based, because
2703 there is no way to distinguish an omitted attribute from a populated attribute
2704 on the receiving side. The `c` member in the example above can be a
2705 non-pointer for this reason. The wsdl2h tool does not generate pointers for
2706 attributes with default/fixed values.
2707
2708 Elements with default or fixed values may be optional and the use of
2709 default/fixed values with elements differs from attributes. The default/fixed
2710 value of an element is only used for elements that are empty in the XML payload
2711 received. Omitted optional elements in the XML payload received are simply
2712 absent; no default/fixed value is assigned.
2713
2714 @note gSOAP 2.8.106 and greater treat `char*` and `wchar_t*` with explicit
2715 default and fixed values differently than previous versions. Versions prior to
2716 2.8.106 assign the default value when the corresponding XML element is absent,
2717 whereas 2.8.106 and greater assign NULL when the XML element is absent, exactly
2718 as documented in this updated version of this document. To revert to the old
2719 behavior, use <b>`soapcpp2 -z4`</b> option <b>`-z4`</b>. The change affects
2720 members `char* f` and `char* l` (see below).
2721
2722 A record class (can be a struct in C) with fixed values for attributes and
2723 elements is declared as follows:
2724
2725 ~~~{.cpp}
2726 class ns__record_with_fixed
2727 {
2728 public:
2729 @ std::string g == "G"; // optional XML attribute with fixed value "G"
2730 @ std::string h 1 == "H"; // required XML attribute with fixed value "H"
2731 @ std::string *i == "I"; // optional XML attribute with fixed value "I"
2732 std::string j 0 == "J"; // optional XML element with fixed value "J"
2733 std::string k == "K"; // required XML element with fixed value "K"
2734 std::string *l == "L"; // optional XML element with fixed value "L"
2735 ...
2736 };
2737 ~~~
2738
2739 With C `char*` (or `const char*`, `const wchar_t*`) strings in a struct, this
2740 becomes:
2741
2742 ~~~{.cpp}
2743 struct ns__record_with_fixed
2744 {
2745 @ char* g == "G"; // optional XML attribute with fixed value "G"
2746 @ char* h 1 == "H"; // required XML attribute with fixed value "H"
2747 char* k 1 == "K"; // required XML element with fixed value "K"
2748 char* l == "L"; // optional XML element with fixed value "L"
2749 ...
2750 };
2751 ~~~
2752
2753 The XML schema validation rules for the examples above are as follows:
2754
2755 Member | Notes
2756 ------ | ---------------------------------------------------------------------
2757 `a` | attribute may appear once; if it does not appear its value is "A", otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns the default value "A")
2758 `b` | has no effect when parsing XML (but note: instantiating `ns__record_with_default` assigns the default value "B")
2759 `c` | attribute may appear once; if it does not appear its value is "C", otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns NULL)
2760 `d` | element may appear once; if it does not appear or if it is empty, its value is "D"; otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns the default value "D")
2761 `e` | has no effect when parsing XML (but note: instantiating `ns__record_with_default` assigns the default value "E")
2762 `f` | element may appear once; if it does not appear it is not provided; if it does appear and it is empty, its value is "F"; otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns NULL)
2763 `g` | attribute may appear once; if it does not appear its value is "G", if it does not appear its value is "G" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "G")
2764 `h` | attribute must appear once, its value must be "H" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "H")
2765 `i` | attribute may appear once; if it does not appear its value is "I", if it does not appear its value is "I" (also note: instantiating `ns__record_with_fixed` assigns NULL)
2766 `j` | element may appear once, if it does not appear it is not provided; if it does appear and it is empty, its value is "J"; if it does appear and it is not empty, its value must be "J" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "J")
2767 `k` | element must appear once, its value must be "K" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "K")
2768 `l` | element may appear once, if it does not appear it is not provided; if it does appear and it is empty, its value is "J"; if it does appear and it is not empty, its value must be "J" (also note: instantiating `ns__record_with_fixed` assigns NULL)
2769
2770 Members of type `char[N]` (fixed length string) can have default and fixed
2771 values, when <b>`soapcpp2 -b`</b> option <b>`-b`</b> is used. Also `char**`
2772 (pointer to a string) members can have default and fixed values. However,
2773 members of this type will be initialized to NULL. The default/fixed values
2774 will be assigned with the same rules as for `char*` when deserialized from XML.
2775
2776 @see Section [operations on classes and structs](#toxsd9-14).
2777
2778 🔝 [Back to table of contents](#)
2779
2780 ### Attribute members {#toxsd9-5}
2781
2782 Class and struct data members are declared as XML attributes by annotating
2783 their type with a `@` qualifier:
2784
2785 ~~~{.cpp}
2786 class ns__record
2787 {
2788 public:
2789 @ std::string name; // required (non-pointer means required)
2790 @ uint64_t SSN; // required (non-pointer means required)
2791 ns__record *spouse; // optional (pointer means minOccurs=0)
2792 };
2793 ~~~
2794
2795 This class maps to a complexType in the soapcpp2-generated XML schema:
2796
2797 <div class="alt">
2798 ~~~{.xml}
2799 <complexType name="record">
2800 <sequence>
2801 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" nillable="true"/>
2802 </sequence>
2803 <attribute name="name" type="xsd:string" use="required"/>
2804 <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2805 </complexType>
2806 ~~~
2807 </div>
2808
2809 An example XML instance of `ns__record` is:
2810
2811 <div class="alt">
2812 ~~~{.xml}
2813 <ns:record xmlns:ns="urn:types" name="Joe" SSN="1234567890">
2814 <spouse name="Jane" SSN="1987654320">
2815 </spouse>
2816 </ns:record>
2817 ~~~
2818 </div>
2819
2820 Attribute data members are restricted to primitive types (`bool`, `enum`,
2821 `time_t`, numeric and string types), `xsd__hexBinary`, `xsd__base64Binary`, and
2822 custom serializers, such as `xsd__dateTime`. Custom serializers for types that
2823 may be used as attributes should define `soap_s2T` and `soap_T2s` functions that
2824 convert values of type `T` to strings and back.
2825
2826 Attribute data members can be pointers and smart pointers to these types, which
2827 permits attributes to be optional.
2828
2829 🔝 [Back to table of contents](#)
2830
2831 ### Backtick XML tags {#toxsd9-5-1}
2832
2833 The XML tag name of a class/struct member is the name of the member with the
2834 usual XML tag translation, see [colon notation](#toxsd2).
2835
2836 To override the standard translation of identifier names to XML tag names of
2837 attributes and elements, add the XML tag name in backticks (requires gSOAP
2838 2.8.30 or greater):
2839
2840 ~~~{.cpp}
2841 class ns__record
2842 {
2843 public:
2844 @ std::string name `full-name`;
2845 @ uint64_t SSN `tax-id`;
2846 ns__record *spouse `married-to`;
2847 };
2848 ~~~
2849
2850 This class maps to a complexType in the soapcpp2-generated XML schema:
2851
2852 <div class="alt">
2853 ~~~{.xml}
2854 <complexType name="record">
2855 <sequence>
2856 <element name="married-to" type="ns:record" minOccurs="0" maxOccurs="1"/>
2857 </sequence>
2858 <attribute name="full-name" type="xsd:string" use="required"/>
2859 <attribute name="tax-id" type="xsd:unsignedLong" use="required"/>
2860 </complexType>
2861 ~~~
2862 </div>
2863
2864 An example XML instance of `ns__record` is:
2865
2866 <div class="alt">
2867 ~~~{.xml}
2868 <ns:record xmlns:ns="urn:types" full-name="Joe" tax-id="1234567890">
2869 <married-to full-name="Jane" tax-id="1987654320">
2870 </married-to>
2871 </ns:record>
2872 ~~~
2873 </div>
2874
2875 A backtick XML tag name may contain any non-empty sequence of ASCII and UTF-8
2876 characters except white space and the backtick character. A backtick tag can
2877 be combined with member constraints and default member initializers:
2878
2879 ~~~{.cpp}
2880 @ uint64_t SSN `tax-id` 0:1 = 999;
2881 ~~~
2882
2883 🔝 [Back to table of contents](#)
2884
2885 ### Qualified and unqualified members {#toxsd9-6}
2886
2887 Class, struct, and union data members are mapped to namespace qualified or
2888 unqualified tag names of local elements and attributes. If a data member has
2889 no prefix then the default form of qualification is applied based on the
2890 element/attribute form that is declared with the XML schema of the class, struct,
2891 or union type. If the member name has a namespace prefix by colon notation,
2892 then the prefix overrules the default (un)qualified form. Therefore,
2893 [colon notation](#toxsd2) is an effective mechanism to control qualification of
2894 tag names of individual members of classes, structs, and unions.
2895
2896 The XML schema elementFormDefault and attributeFormDefault declarations control
2897 the tag name qualification of local elements and attributes, respectively.
2898
2899 - "unqualified" indicates that local elements/attributes are not qualified with
2900 the namespace prefix.
2901
2902 - "qualified" indicates that local elements/attributes must be qualified with
2903 the namespace prefix.
2904
2905 Individual schema declarations of local elements and attributes may overrule
2906 this by using the form declaration in an XML schema and by using colon notation
2907 to add namespace prefixes to class, struct, and union members in the header
2908 file for soapcpp2.
2909
2910 Consider for example an `ns__record` class in the `ns` namespace in which local
2911 elements are qualified and local attributes are unqualified by default:
2912
2913 ~~~{.cpp}
2914 //gsoap ns schema namespace: urn:types
2915 //gsoap ns schema elementForm: qualified
2916 //gsoap ns schema attributeForm: unqualified
2917 class ns__record
2918 {
2919 public:
2920 @ std::string name;
2921 @ uint64_t SSN;
2922 ns__record *spouse;
2923 };
2924 ~~~
2925
2926 This class maps to a complexType in the soapcpp2-generated XML schema with
2927 targetNamespace "urn:types", elementFormDefault qualified and
2928 attributeFormDefault unqualified:
2929
2930 <div class="alt">
2931 ~~~{.xml}
2932 <schema targetNamespace="urn:types"
2933 ...
2934 elementFormDefault="qualified"
2935 attributeFormDefault="unqualified"
2936 ... >
2937 <complexType name="record">
2938 <sequence>
2939 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1"/>
2940 </sequence>
2941 <attribute name="name" type="xsd:string" use="required"/>
2942 <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2943 </complexType>
2944 </schema>
2945 ~~~
2946 </div>
2947
2948 An example XML instance of `ns__record` is:
2949
2950 <div class="alt">
2951 ~~~{.xml}
2952 <ns:record xmlns:ns="urn:types" name="Joe" SSN="1234567890">
2953 <ns:spouse> name="Jane" SSN="1987654320">
2954 </ns:spouse>
2955 </ns:record>
2956 ~~~
2957 </div>
2958
2959 Here the root element <i>`<ns:record>`</i> is qualified because it is a root
2960 element of the XML schema with target namespace "urn:types". Its local element
2961 <i>`<ns:spouse>`</i> is namespace qualified because the elementFormDefault of
2962 local elements is qualified. Attributes are unqualified.
2963
2964 The default namespace (un)qualification of local elements and attributes can be
2965 overruled by adding a prefix to the member name by using colon notation:
2966
2967 ~~~{.cpp}
2968 //gsoap ns schema namespace: urn:types
2969 //gsoap ns schema elementForm: qualified
2970 //gsoap ns schema attributeForm: unqualified
2971 class ns__record
2972 {
2973 public:
2974 @ std::string ns:name; // 'ns:' qualified
2975 @ uint64_t SSN;
2976 ns__record *:spouse; // ':' unqualified (empty prefix)
2977 };
2978 ~~~
2979
2980 The colon notation for member <i>`ns:name`</i> forces qualification of its attribute
2981 tag in XML. The colon notation for member <i>`:spouse`</i> removes qualification from
2982 its local element tag:
2983
2984 <div class="alt">
2985 ~~~{.xml}
2986 <schema targetNamespace="urn:types"
2987 ...
2988 elementFormDefault="unqualified"
2989 attributeFormDefault="unqualified"
2990 ... >
2991 <complexType name="record">
2992 <sequence>
2993 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" form="unqualified"/>
2994 </sequence>
2995 <attribute name="name" type="xsd:string" use="required" form="qualified"/>
2996 <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2997 </complexType>
2998 </schema>
2999 ~~~
3000 </div>
3001
3002 XML instances of `ns__record` have unqualified spouse elements and qualified
3003 ns:name attributes:
3004
3005 <div class="alt">
3006 ~~~{.xml}
3007 <ns:record xmlns:ns="urn:types" ns:name="Joe" SSN="1234567890">
3008 <spouse> ns:name="Jane" SSN="1987654320">
3009 </spouse>
3010 </ns:record>
3011 ~~~
3012 </div>
3013
3014 Members of a class or struct can also be prefixed using the `prefix__name`
3015 convention or using colon notation `prefix:name`. However, this has a
3016 different effect by referring to global (root) elements and attributes, see
3017 [document root element definitions](#toxsd9-7).
3018
3019 [Backtick XML tags](#toxsd9-5-1) can be used in place of the member name
3020 annotations and will achieve the same effect as described when these tag names
3021 are (un)qualified (requires gSOAP 2.8.30 or greater).
3022
3023 @note You must declare a target namespace with a `//gsoap ns schema namespace:`
3024 directive to enable the `elementForm` and `attributeForm` directives in order
3025 to generate valid XML schemas with soapcpp2. See [directives](#directives) for
3026 more details.
3027
3028 🔝 [Back to table of contents](#)
3029
3030 ### Defining document root elements {#toxsd9-7}
3031
3032 To define and reference XML document root elements we use type names that start
3033 with an underscore:
3034
3035 ~~~{.cpp}
3036 class _ns__record
3037 ~~~
3038
3039 Alternatively, we can use a `typedef` to define a document root element with a
3040 given type:
3041
3042 ~~~{.cpp}
3043 typedef ns__record _ns__record;
3044 ~~~
3045
3046 This `typedef` maps to a global root element that is added to the
3047 soapcpp2-generated XML schema:
3048
3049 <div class="alt">
3050 ~~~{.xml}
3051 <element name="record" type="ns:record"/>
3052 ~~~
3053 </div>
3054
3055 An example XML instance of `_ns__record` is:
3056
3057 <div class="alt">
3058 ~~~{.xml}
3059 <ns:record xmlns:ns="urn:types">
3060 <name>Joe</name>
3061 <SSN>1234567890</SSN>
3062 <spouse>
3063 <name>Jane</name>
3064 <SSN>1987654320</SSN>
3065 </spouse>
3066 </ns:record>
3067 ~~~
3068 </div>
3069
3070 Global-level element/attribute definitions are also referenced and/or added to
3071 the generated XML schema when serializable data members reference these by
3072 their qualified name:
3073
3074 ~~~{.cpp}
3075 typedef std::string _ns__name 1 : 100;
3076 class _ns__record
3077 {
3078 public:
3079 @ _QName xsi__type; // built-in XSD attribute xsi:type
3080 _ns__name ns__name; // ref to global ns:name element
3081 uint64_t SSN;
3082 _ns__record *spouse;
3083 };
3084 ~~~
3085
3086 These types map to the following comonents in the soapcpp2-generated XML
3087 schema:
3088
3089 <div class="alt">
3090 ~~~{.xml}
3091 <simpleType name="name">
3092 <restriction base="xsd:string">
3093 <minLength value="1"/>
3094 <maxLength value="100"/>
3095 </restriction>
3096 </simpleType>
3097 <element name="name" type="ns:name"/>
3098 <complexType name="record">
3099 <sequence>
3100 <element ref="ns:name" minOccurs="1" maxOccurs="1"/>
3101 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3102 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1"/>
3103 </sequence>
3104 <attribute ref="xsi:type" use="optional"/>
3105 </complexType>
3106 <element name="record" type="ns:record"/>
3107 ~~~
3108 </div>
3109
3110 Use only use qualified member names when their types match the global-level
3111 element types that they refer to. For example:
3112
3113 ~~~{.cpp}
3114 typedef std::string _ns__name; // global element ns:name of type xsd:string
3115 class _ns__record
3116 {
3117 public:
3118 int ns__name; // BAD: global element ns:name is NOT type int
3119 _ns__record ns__record; // OK: ns:record is a global-level root element
3120 ...
3121 };
3122 ~~~
3123
3124 Therefore, we recommend to use qualified member names only when necessary to
3125 refer to standard XSD elements and attributes, such as `xsi__type`, and
3126 `xsd__lang`.
3127
3128 By contrast, colon notation has the desired effect to (un)qualify local tag
3129 names by overruling the default element/attribute namespace qualification, see
3130 [qualified and unqualified members](#toxsd9-6).
3131
3132 As an alternative to prefixing member names, use the backtick tag (requires
3133 gSOAP 2.8.30 or greater):
3134
3135 ~~~{.cpp}
3136 typedef std::string _ns__name 1 : 100;
3137 class _ns__record
3138 {
3139 public:
3140 @ _QName t <i>`xsi:type`</i>; // built-in XSD attribute xsi:type
3141 _ns__name s <i>`ns:name`</i>; // ref to global ns:name element
3142 uint64_t SSN;
3143 _ns__record *spouse;
3144 };
3145 ~~~
3146
3147 🔝 [Back to table of contents](#)
3148
3149 ### (Smart) pointer members and their occurrence constraints {#toxsd9-8}
3150
3151 A public pointer-typed data member is serialized by following its (smart)
3152 pointer(s) to the value pointed to. To serialize pointers to dynamic arrays of
3153 data, please see the next section on
3154 [container and array members and their occurrence constraints](#toxsd9-9).
3155
3156 Pointers that are NULL and smart pointers that are empty are serialized to
3157 produce omitted element and attribute values, unless an element is required
3158 and is nillable (struct/class members marked with `nullptr`) in which case the
3159 element is rendered as an empty element with <i>`xsi:nil="true"`</i>.
3160
3161 To control the occurrence requirements of pointer-based data members,
3162 occurrence constraints are associated with data members in the form of a range
3163 `minOccurs : maxOccurs`. For non-repeatable (meaning, not a container or array)
3164 data members, there are only three reasonable occurrence constraints:
3165
3166 - `0:0` means that this element or attribute is prohibited.
3167
3168 - `0:1` means that this element or attribute is optional.
3169
3170 - `1:1` means that this element or attribute is required.
3171
3172 Pointer-based data members have a default `0:1` occurrence constraint, making
3173 them optional, and their XML schema local element/attribute definition is
3174 marked as nillable. Non-pointer data members have a default `1:1` occurence
3175 constraint, making them required.
3176
3177 A `nullptr` occurrence constraint may be applicable to required elements that
3178 are nillable pointer types, thus `nullptr 1:1`. This indicates that the
3179 element is nillable (can be `NULL` or `nullptr`). A pointer data member that
3180 is explicitly marked as required and nillable with `nullptr 1:1` will be
3181 serialized as an element with an <i>`xsi:nil`</i> attribute, thus effectively
3182 revealing the NULL property of its value.
3183
3184 A non-pointer data member that is explicitly marked as optional with `0:1` will
3185 be set to its default value when no XML value is presented to the deserializer.
3186 A default value can be assigned to a data member that has a primitive type or
3187 is a (smart) pointer to primitive type.
3188
3189 Consider for example:
3190
3191 ~~~{.cpp}
3192 class ns__record
3193 {
3194 public:
3195 std::shared_ptr<std::string> name; // optional (pointer means minOccurs=0)
3196 uint64_t SSN 0:1 = 999; // force optional with default 999
3197 ns__record *spouse nullptr 1:1; // force required and nillabe when absent
3198 };
3199 ~~~
3200
3201 This class maps to a complexType in the soapcpp2-generated XML schema:
3202
3203 <div class="alt">
3204 ~~~{.xml}
3205 <complexType name="record">
3206 <sequence>
3207 <element name="name" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3208 <element name="SSN" type="xsd:unsignedLong" minOccurs="0" maxOccurs="1" default="999"/>
3209 <element name="spouse" type="ns:record" minOccurs="1" maxOccurs="1" nillable="true"/>
3210 </sequence>
3211 </complexType>
3212 ~~~
3213 </div>
3214
3215 An example XML instance of `ns__record` with its `name` string value set to
3216 `Joe`, `SSN` set to its default, and `spouse` set to NULL:
3217
3218 <div class="alt">
3219 ~~~{.xml}
3220 <ns:record xmlns:ns="urn:types" ...>
3221 <name>Joe</name>
3222 <SSN>999</SSN>
3223 <spouse xsi:nil="true"/>
3224 </ns:record>
3225 ~~~
3226 </div>
3227
3228 @note In general, a smart pointer is simply declared as a `volatile` template
3229 in a interface header file for soapcpp2:
3230 ~~~{.cpp}
3231 volatile template <class T> class NAMESPACE::shared_ptr;
3232 ~~~
3233
3234 @note The soapcpp2 tool generates code that uses `NAMESPACE::shared_ptr` and
3235 `NAMESPACE::make_shared` to create shared pointers to objects, where
3236 `NAMESPACE` is any valid C++ namespace such as `std` and `boost` if you have
3237 Boost installed.
3238
3239 🔝 [Back to table of contents](#)
3240
3241 ### Container and array members and their occurrence constraints {#toxsd9-9}
3242
3243 Class and struct data member types that are containers `std::deque`,
3244 `std::list`, `std::vector` and `std::set` are serialized as a collection of
3245 the values they contain. You can also serialize dynamic arrays, which is the
3246 alternative for C to store collections of data. Let's start with containers.
3247
3248 You can use `std::deque`, `std::list`, `std::vector`, and `std::set` containers
3249 by importing:
3250
3251 ~~~{.cpp}
3252 #import "import/stl.h" // import all containers
3253 #import "import/stldeque.h" // import deque
3254 #import "import/stllist.h" // import list
3255 #import "import/stlvector.h" // import vector
3256 #import "import/stlset.h" // import set
3257 ~~~
3258
3259 For example, to use a vector data mamber to store names in a record:
3260
3261 ~~~{.cpp}
3262 #import "import/stlvector.h"
3263 class ns__record
3264 {
3265 public:
3266 std::vector<std::string> names;
3267 uint64_t SSN;
3268 };
3269 ~~~
3270
3271 To limit the number of names in the vector within reasonable bounds, occurrence
3272 constraints are associated with the container. Occurrence constraints are of
3273 the form `minOccurs : maxOccurs`:
3274
3275 ~~~{.cpp}
3276 #import "import/stlvector.h"
3277 class ns__record
3278 {
3279 public:
3280 std::vector<std::string> names 1:10;
3281 uint64_t SSN;
3282 };
3283 ~~~
3284
3285 This class maps to a complexType in the soapcpp2-generated XML schema:
3286
3287 <div class="alt">
3288 ~~~{.xml}
3289 <complexType name="record">
3290 <sequence>
3291 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="10"/>
3292 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3293 </sequence>
3294 </complexType>
3295 ~~~
3296 </div>
3297
3298 @note In general, a container is simply declared as a template in an interface
3299 header file for soapcpp2. All class templates are considered containers
3300 (except when declared `volatile`, see smart pointers). For example,
3301 `std::vector` is declared in <i>`gsoap/import/stlvector.h`</i> as:
3302 ~~~{.cpp}
3303 template <class T> class std::vector;
3304 ~~~
3305
3306 @note You can define and use your own containers. The soapcpp2 tool generates
3307 code that uses the following members of the `template <typename T> class C`
3308 container:
3309 ~~~{.cpp}
3310 void C::clear()
3311 C::iterator C::begin()
3312 C::const_iterator C::begin() const
3313 C::iterator C::end()
3314 C::const_iterator C::end() const
3315 size_t C::size() const
3316 C::iterator C::insert(C::iterator pos, const T& val)
3317 ~~~
3318
3319 @note For more details see the example `simple_vector` container with
3320 documentation in the package under <i>`gsoap/samples/template`</i>.
3321
3322 Because C does not support a container template library, we can use a
3323 dynamically-sized array of values. This array is declared as a size-pointer
3324 pair of members within a struct or class. The array size information is stored
3325 in a special size tag member with the name `__size` or `__sizeX`, where `X` can
3326 be any name, or by an `$int` member to identify the member as a special size
3327 tag:
3328
3329 ~~~{.cpp}
3330 struct ns__record
3331 {
3332 $ int sizeofnames; // array size
3333 char* *names; // array of char* names
3334 uint64_t SSN;
3335 };
3336 ~~~
3337
3338 This struct maps to a complexType in the soapcpp2-generated XML schema:
3339
3340 <div class="alt">
3341 ~~~{.xml}
3342 <complexType name="record">
3343 <sequence>
3344 <element name="name" type="xsd:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/>
3345 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3346 </sequence>
3347 </complexType>
3348 ~~~
3349 </div>
3350
3351 To limit the number of names in the array within reasonable bounds, occurrence
3352 constraints are associated with the array size member. Occurrence constraints
3353 are of the form `minOccurs : maxOccurs`:
3354
3355 ~~~{.cpp}
3356 struct ns__record
3357 {
3358 $ int sizeofnames 1:10; // array size 1..10
3359 char* *names; // array of one to ten char* names
3360 uint64_t SSN;
3361 };
3362 ~~~
3363
3364 This struct maps to a complexType in the soapcpp2-generated XML schema:
3365
3366 <div class="alt">
3367 ~~~{.xml}
3368 <complexType name="record">
3369 <sequence>
3370 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="10" nillable="true"/>
3371 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3372 </sequence>
3373 </complexType>
3374 ~~~
3375 </div>
3376
3377 Arrays can also be declared as nested elements, similar to SOAP-encoded dynamic arrays, and these arrays can be used with or without SOAP applications. This requires a separate struct or class with the name of the SOAP array, which should not be qualified with a namespace prefix:
3378
3379 ~~~{.cpp}
3380 struct ArrayOfstring
3381 {
3382 char* *__ptr 1:100; // array of 1..100 strings
3383 int __size; // array size
3384 };
3385 struct ns__record
3386 {
3387 struct ArrayOfstring names; // array of char* names
3388 uint64_t SSN;
3389 };
3390 ~~~
3391
3392 The `ns__record` struct maps to a complexType that references the <i>`ArrayOfstring`</i> complexType with an sequence of 1 to 100 <i>`item`</i> elements:
3393
3394 <div class="alt">
3395 ~~~{.xml}
3396 <complexType name="ArrayOfstring">
3397 <sequence>
3398 <element name="item" type="xsd:string" minOccurs="1" maxOccurs="100"/>
3399 </sequence>
3400 </complexType>
3401 <complexType name="record">
3402 <sequence>
3403 <element name="names" type="ns:ArrayOfstring" minOccurs="1" maxOccurs="1"/>
3404 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3405 </sequence>
3406 </complexType>
3407 ~~~
3408 </div>
3409
3410 To change the <i>`item`</i> element name in the WSDL, XML schema, and XML messages, use `__ptrName` where `Name` is the name you want to use.
3411
3412 @note When <b>`soapcpp2 -e`</b> option <b>`-e`</b> is used, the <i>`ArrayOfstring`</i> becomes a SOAP-encoded array for SOAP 1.1/1.2 RPC encoded messaging:
3413 <div class="alt">
3414 ~~~{.xml}
3415 <import namespace="http://schemas.xmlsoap.org/soap/encoding/"/>
3416 <complexType name="ArrayOfstring">
3417 <complexContent>
3418 <restriction base="SOAP-ENC:Array">
3419 <sequence>
3420 <element name="item" type="xsd:string" minOccurs="1" maxOccurs="100"/>
3421 </sequence>
3422 <attribute ref="SOAP-ENC:arrayType" WSDL:arrayType="xsd:string[]"/>
3423 </restriction>
3424 </complexContent>
3425 </complexType>
3426 <complexType name="record">
3427 <sequence>
3428 <element name="names" type="ns:ArrayOfstring" minOccurs="1" maxOccurs="1"/>
3429 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3430 </sequence>
3431 </complexType>
3432 ~~~
3433 </div>
3434
3435 Fixed-size arrays can be used to store a fixed number of values:
3436
3437 ~~~{.cpp}
3438 struct ns__record
3439 {
3440 char* names[10]; // array of 10 char* names
3441 uint64_t SSN;
3442 };
3443 ~~~
3444
3445 The fixed-size array is similar to a SOAP-encoded array, which can be used with or without SOAP applications. This struct maps to a complexType that references a <i>`Array10Ofstring`</i> complexType with ten <i>`item`</i> elements:
3446
3447 <div class="alt">
3448 ~~~{.xml}
3449 <complexType name="record">
3450 <sequence>
3451 <element name="names" type="ns:Array10Ofstring" minOccurs="1" maxOccurs="1"/>
3452 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3453 </sequence>
3454 </complexType>
3455 <complexType name="Array10Ofstring">
3456 <sequence>
3457 <element name="item" type="xsd:string" minOccurs="0" maxOccurs="10"/>
3458 </sequence>
3459 </complexType>
3460 ~~~
3461 </div>
3462
3463 @note When <b>`soapcpp2 -e`</b> option <b>`-e`</b> is used, the <i>`Array10Ofstring`</i> becomes a SOAP-encoded array for SOAP 1.1/1.2 RPC encoded messaging, see previous note.
3464
3465 🔝 [Back to table of contents](#)
3466
3467 ### Sequencing with hidden members {#toxsd9-10}
3468
3469 A member becomes a hidden XML element, i.e. not visibly rendered in XML, when
3470 its name starts with a double underscore. This makes it possible to sequence a
3471 collection of data members, basically by forming a sequence of elements that
3472 can be optional or repeated together.
3473
3474 To create a sequence of members that are optional, use a pointer-based hidden
3475 member that is a struct with the collection of members to sequence:
3476
3477 ~~~{.cpp}
3478 struct ns__record
3479 {
3480 std::string name; // required name
3481 struct __ns__optional
3482 {
3483 uint64_t SSN; // SSN in optional group
3484 std::string phone; // phone number in optional group
3485 } *__optional; // optional group
3486 };
3487 ~~~
3488
3489 Here we used a hidden struct type `__ns__optional` which starts with a double
3490 underscore, because we do not want to define a new global type for the XML
3491 schema we generate. We just need a unique name for a structure that sequences
3492 the two members.
3493
3494 This struct maps to a complexType in the soapcpp2-generated XML schema:
3495
3496 <div class="alt">
3497 ~~~{.xml}
3498 <complexType name="record">
3499 <sequence>
3500 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3501 <sequence minOccurs="0" maxOccurs="1">
3502 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3503 <element name="phone" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3504 </sequence>
3505 </sequence>
3506 </complexType>
3507 ~~~
3508 </div>
3509
3510 The `name` member is a required element of the <i>`ns:record`</i> complexType.
3511 The <i>`ns:record`</i> complexType has an optional sequence of `SSN` and
3512 `phone` elements.
3513
3514 To create repetitions of a sequence of members, use an array as follows:
3515
3516 ~~~{.cpp}
3517 struct ns__record
3518 {
3519 std::string name; // required name
3520 $ int sizeofarray; // size of group array
3521 struct __ns__array
3522 {
3523 uint64_t SSN; // SSN in group
3524 std::string phone; // phone number in group
3525 } *__array; // group array
3526 };
3527 ~~~
3528
3529 This struct maps to a complexType in the soapcpp2-generated XML schema:
3530
3531 <div class="alt">
3532 ~~~{.xml}
3533 <complexType name="record">
3534 <sequence>
3535 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3536 <sequence minOccurs="0" maxOccurs="unbounded">
3537 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3538 <element name="phone" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3539 </sequence>
3540 </sequence>
3541 </complexType>
3542 ~~~
3543 </div>
3544
3545 The `name` member is a required element of the <i>`ns:record`</i> complexType.
3546 The <i>`ns:record`</i> complexType has a potentially unbounded sequence of
3547 `SSN` and `phone` elements. You can specify array bounds instead of zero to
3548 unbounded, see [container and array members and their occurrence constraints](#toxsd9-9).
3549
3550 The XML value space consists of a sequence of SSN and phone elements:
3551
3552 <div class="alt">
3553 ~~~{.xml}
3554 <ns:record>
3555 <name>numbers</name>
3556 <SSN>1234567890</SSN>
3557 <phone>555-123-4567</phone>
3558 <SSN>1987654320</SSN>
3559 <phone>555-789-1234</phone>
3560 <SSN>2345678901</SSN>
3561 <phone>555-987-6543</phone>
3562 </ns:record>
3563 ~~~
3564 </div>
3565
3566 🔝 [Back to table of contents](#)
3567
3568 ### Tagged union members {#toxsd9-11}
3569
3570 A union member in a class or in a struct cannot be serialized unless a
3571 discriminating *variant selector* member is provided that tells the serializer
3572 which union field to serialize. This effectively creates a *tagged union*.
3573
3574 The variant selector is associated with the union as a selector-union pair of members.
3575 The variant selector is a member with the name `__union` or `__unionX`, where
3576 `X` can be any name, or by an `$int` member to identify the member as a variant
3577 selector tag:
3578
3579 ~~~{.cpp}
3580 class ns__record
3581 {
3582 public:
3583 $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3584 union ns__choice
3585 {
3586 float x;
3587 int n;
3588 char *s;
3589 } u;
3590 std::string name;
3591 };
3592 ~~~
3593
3594 The variant selector values are auto-generated based on the union name `choice`
3595 and the names of its members `x`, `n`, and `s`:
3596
3597 - `xORnORs = SOAP_UNION_ns__choice_x` when `u.x` is valid.
3598
3599 - `xORnORs = SOAP_UNION_ns__choice_n` when `u.n` is valid.
3600
3601 - `xORnORs = SOAP_UNION_ns__choice_s` when `u.s` is valid.
3602
3603 - `xORnORs = 0` when none are valid (should only be used with great care,
3604 because XSD validation may fail when content is required but absent).
3605
3606 This class maps to a complexType with a sequence and choice in the
3607 soapcpp2-generated XML schema:
3608
3609 <div class="alt">
3610 ~~~{.xml}
3611 <complexType name="record">
3612 <sequence>
3613 <choice>
3614 <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
3615 <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
3616 <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3617 </choice>
3618 <element name="names" type="xsd:string" minOccurs="1" maxOccurs="1" nillable="true"/>
3619 </sequence>
3620 </complexType>
3621 ~~~
3622 </div>
3623
3624 A container or dynamic array of a union requires wrapping the variant selector
3625 and union member in a struct:
3626
3627 ~~~{.cpp}
3628 class ns__record
3629 {
3630 public:
3631 std::vector<
3632 struct ns__data // data with a choice of x, n, or s
3633 {
3634 $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3635 union ns__choice
3636 {
3637 float x;
3638 int n;
3639 char *s;
3640 } u;
3641 }> data; // vector with data
3642 };
3643 ~~~
3644
3645 and an equivalent definition with a dynamic array instead of a `std::vector`
3646 (you can use this in C with structs):
3647
3648 ~~~{.cpp}
3649 class ns__record
3650 {
3651 public:
3652 $ int sizeOfdata; // size of dynamic array
3653 struct ns__data // data with a choice of x, n, or s
3654 {
3655 $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3656 union ns__choice
3657 {
3658 float x;
3659 int n;
3660 char *s;
3661 } u;
3662 } *data; // points to the data array of length sizeOfdata
3663 };
3664 ~~~
3665
3666 This maps to two complexTypes in the soapcpp2-generated XML schema:
3667
3668 <div class="alt">
3669 ~~~{.xml}
3670 <complexType name="data">
3671 <choice>
3672 <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
3673 <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
3674 <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3675 </choice>
3676 </complexType>
3677 <complexType name="record">
3678 <sequence>
3679 <element name="data" type="ns:data" minOccurs="0" maxOccurs="unbounded"/>
3680 </sequence>
3681 </complexType>
3682 ~~~
3683 </div>
3684
3685 The XML value space consists of a sequence of item elements each wrapped in an
3686 data element:
3687
3688 <div class="alt">
3689 ~~~{.xml}
3690 <ns:record xmlns:ns="urn:types" ...>
3691 <data>
3692 <n>123</n>
3693 </data>
3694 <data>
3695 <x>3.1</x>
3696 </data>
3697 <data>
3698 <s>hello</s>
3699 </data>
3700 <data>
3701 <s>world</s>
3702 </data>
3703 </ns:record>
3704 ~~~
3705 </div>
3706
3707 To remove the wrapping data element, simply rename the wrapping struct to
3708 `__ns__data` and the member to `__data` to make this member invisible to the
3709 serializer. The double underscore prefix naming convention is used for the
3710 struct name and member name. Also use a dynamic array instead of a container
3711 (so you can also use this approach in C with structs):
3712
3713 ~~~{.cpp}
3714 class ns__record
3715 {
3716 public:
3717 $ int sizeOfdata; // size of dynamic array
3718 struct __ns__data // contains choice of x, n, or s
3719 {
3720 $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3721 union ns__choice
3722 {
3723 float x;
3724 int n;
3725 char *s;
3726 } u;
3727 } *__data; // points to the data array of length sizeOfdata
3728 };
3729 ~~~
3730
3731 This maps to a complexType in the soapcpp2-generated XML schema:
3732
3733 <div class="alt">
3734 ~~~{.xml}
3735 <complexType name="record">
3736 <sequence minOccurs="0" maxOccurs="unbounded">
3737 <choice>
3738 <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
3739 <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
3740 <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3741 </choice>
3742 </sequence>
3743 </complexType>
3744 ~~~
3745 </div>
3746
3747 The XML value space consists of a sequence of <i>`<x>`</i>, <i>`<n>`</i>, and/or <i>`<s>`</i>
3748 elements:
3749
3750 <div class="alt">
3751 ~~~{.xml}
3752 <ns:record xmlns:ns="urn:types" ...>
3753 <n>123</n>
3754 <x>3.1</x>
3755 <s>hello</s>
3756 <s>world</s>
3757 </ns:record>
3758 ~~~
3759 </div>
3760
3761 Please note that structs, classes, and unions are unnested by soapcpp2 (as in
3762 the C standard of nested structs and unions). Therefore, the `ns__choice`
3763 union in the `ns__record` class is redeclared at the top level despite its
3764 nesting within the `ns__record` class. This means that you will have to choose
3765 a unique name for each nested struct, class, and union.
3766
3767 🔝 [Back to table of contents](#)
3768
3769 ### Tagged void pointer members {#toxsd9-12}
3770
3771 To serialize data pointed to by `void*` requires run-time type information that
3772 tells the serializer what type of data to serialize by means of a *tagged void
3773 pointer*. This type information is stored in a special type tag member of a
3774 struct/class with the name `__type` or `__typeX`, where `X` can be any name, or
3775 alternatively by an `$int` special member of any name as a type tag:
3776
3777 ~~~{.cpp}
3778 class ns__record
3779 {
3780 public:
3781 $ int typeOfdata; // type tag with values SOAP_TYPE_T
3782 void *data; // points to some data of type T
3783 };
3784 ~~~
3785
3786 A type tag member has nonzero values `SOAP_TYPE_T` where `T` is the name of a
3787 struct/class or the name of a primitive type, such as `int`, `std__string` (for
3788 `std::string`), `string` (for `char*`).
3789
3790 This class maps to a complexType with a sequence in the soapcpp2-generated
3791 XML schema:
3792
3793 <div class="alt">
3794 ~~~{.xml}
3795 <complexType name="record">
3796 <sequence>
3797 <element name="data" type="xsd:anyType" minOccurs="0" maxOccurs="1"/>
3798 </sequence>
3799 </complexType>
3800 ~~~
3801 </div>
3802
3803 The XML value space consists of the XML value space of the type with the
3804 addition of an <i>`xsi:type`</i> attribute to the enveloping element:
3805
3806 <div class="alt">
3807 ~~~{.xml}
3808 <ns:record xmlns:ns="urn:types" ...>
3809 <data xsi:type="xsd:int">123</data>
3810 </ns:record>
3811 ~~~
3812 </div>
3813
3814 This <i>`xsi:type`</i> attribute is important for the receiving end to distinguish
3815 the type of data to instantiate. The receiver cannot deserialize the data
3816 without an <i>`xsd:type`</i> attribute.
3817
3818 You can find the `SOAP_TYPE_T` name of each serializable type in the
3819 auto-generated <i>`soapStub.h`</i> file.
3820
3821 Also all serializable C++ classes have a virtual `int T::soap_type()` member
3822 that returns their `SOAP_TYPE_T` value that you can use.
3823
3824 When the `void*` pointer is NULL or when `typeOfdata` is zero, the data is not
3825 serialized.
3826
3827 A container or dynamic array of `void*` pointers to <i>`xsd:anyType`</i> data
3828 requires wrapping the type tag and `void*` members in a struct:
3829
3830 ~~~{.cpp}
3831 class ns__record
3832 {
3833 public:
3834 std::vector<
3835 struct ns__data // data with an xsd:anyType item
3836 {
3837 $ int typeOfitem; // type tag with values SOAP_TYPE_T
3838 void *item; // points to some item of type T
3839 }> data; // vector with data
3840 };
3841 ~~~
3842
3843 and an equivalent definition with a dynamic array instead of a `std::vector`
3844 (you can use this in C with structs):
3845
3846 ~~~{.cpp}
3847 class ns__record
3848 {
3849 public:
3850 $ int sizeOfdata; // size of dynamic array
3851 struct ns__data // data with an xsd:anyType item
3852 {
3853 $ int typeOfitem; // type tag with values SOAP_TYPE_T
3854 void *item; // points to some item of type T
3855 } *data; // points to the data array of length sizeOfdata
3856 };
3857 ~~~
3858
3859 This maps to two complexTypes in the soapcpp2-generated XML schema:
3860
3861 <div class="alt">
3862 ~~~{.xml}
3863 <complexType name="data">
3864 <sequence>
3865 <element name="item" type="xsd:anyType" minOccurs="1" maxOccurs="1" nillable="true"/>
3866 </sequence>
3867 </complexType>
3868 <complexType name="record">
3869 <sequence>
3870 <element name="data" type="ns:data" minOccurs="0" maxOccurs="unbounded"/>
3871 </sequence>
3872 </complexType>
3873 ~~~
3874 </div>
3875
3876 The XML value space consists of a sequence of item elements each wrapped in a
3877 data element:
3878
3879 <div class="alt">
3880 ~~~{.xml}
3881 <ns:record xmlns:ns="urn:types" ...>
3882 <data>
3883 <item xsi:type="xsd:int">123</item>
3884 </data>
3885 <data>
3886 <item xsi:type="xsd:double">3.1</item>
3887 </data>
3888 <data>
3889 <item xsi:type="xsd:string">abc</item>
3890 </data>
3891 </ns:record>
3892 ~~~
3893 </div>
3894
3895 To remove the wrapping data elements, simply rename the wrapping struct and
3896 member to `__data` to make this member invisible to the serializer with the
3897 double underscore prefix naming convention. Also use a dynamic array instead
3898 of a container (you can use this in C with structs):
3899
3900 ~~~{.cpp}
3901 class ns__record
3902 {
3903 public:
3904 $ int sizeOfdata; // size of dynamic array
3905 struct __data // contains xsd:anyType item
3906 {
3907 $ int typeOfitem; // type tag with values SOAP_TYPE_T
3908 void *item; // points to some item of type T
3909 } *__data; // points to the data array of length sizeOfdata
3910 };
3911 ~~~
3912
3913 This maps to a complexType in the soapcpp2-generated XML schema:
3914
3915 <div class="alt">
3916 ~~~{.xml}
3917 <complexType name="record">
3918 <sequence minOccurs="0" maxOccurs="unbounded">
3919 <element name="item" type="xsd:anyType" minOccurs="1" maxOccurs="1"/>
3920 </sequence>
3921 </complexType>
3922 ~~~
3923 </div>
3924
3925 The XML value space consists of a sequence of data elements:
3926
3927 <div class="alt">
3928 ~~~{.xml}
3929 <ns:record xmlns:ns="urn:types" ...>
3930 <item xsi:type="xsd:int">123</item>
3931 <item xsi:type="xsd:double">3.1</item>
3932 <item xsi:type="xsd:string">abc</item>
3933 </ns:record>
3934 ~~~
3935 </div>
3936
3937 Again, please note that structs, classes, and unions are unnested by soapcpp2
3938 (as in the C standard of nested structs and unions). Therefore, the `__data`
3939 struct in the `ns__record` class is redeclared at the top level despite its
3940 nesting within the `ns__record` class. This means that you will have to choose
3941 a unique name for each nested struct, class, and union.
3942
3943 @see Section [XSD type bindings](#typemap2).
3944
3945 🔝 [Back to table of contents](#)
3946
3947 ### Adding get and set methods {#toxsd9-13}
3948
3949 A public `get` method may be added to a class or struct, which will be
3950 triggered by the deserializer. This method will be invoked right after the
3951 instance is populated by the deserializer. The `get` method can be used to
3952 update or verify deserialized content. It should return `SOAP_OK` or set
3953 `soap::error` to a nonzero error code and return it.
3954
3955 A public `set` method may be added to a class or struct, which will be
3956 triggered by the serializer. The method will be invoked just before the
3957 instance is serialized. Likewise, the `set` method should return `SOAP_OK` or
3958 set set `soap::error` to a nonzero error code and return it.
3959
3960 For example, adding a `set` and `get` method to a class declaration:
3961
3962 ~~~{.cpp}
3963 class ns__record
3964 {
3965 public:
3966 int set(struct soap*); // triggered before serialization
3967 int get(struct soap*); // triggered after deserialization
3968 ...
3969 };
3970 ~~~
3971
3972 To add these and othe rmethods to classes and structs with wsdl2h and
3973 <i>`typemap.dat`</i>, please see [class/struct member additions](#typemap3).
3974
3975 🔝 [Back to table of contents](#)
3976
3977 ### Operations on classes and structs {#toxsd9-14}
3978
3979 The following functions/macros are generated by soapcpp2 for each type `T`,
3980 which should make it easier to send, receive, and copy XML data in C and in
3981 C++:
3982
3983 - `int soap_write_T(struct soap*, T*)` writes an instance of `T` to a file via
3984 file descriptor `int soap::sendfd)` or to a stream via `std::ostream
3985 *soap::os` (C++ only) or saves into a NUL-terminated string by setting
3986 `const char **soap::os` to a string pointer to be set (C only). Returns
3987 `SOAP_OK` on success or an error code, also stored in `soap::error`.
3988
3989 - `int soap_read_T(struct soap*, T*)` reads an instance of `T` from a file via
3990 file descriptor `int soap::recvfd)` or from a stream via `std::istream
3991 *soap::is` (C++ only) or reads from a NUL-termianted string `const char
3992 *soap::is` (C only). Returns `SOAP_OK` on success or an error code, also
3993 stored in `soap::error`.
3994
3995 - `void soap_default_T(struct soap*, T*)` sets an instance `T` to its default
3996 value, resetting members of a struct to their initial values (for classes we
3997 use method `T::soap_default`, see below). If `T` is a struct that has a
3998 `soap` pointer member to a `::soap` context then this pointer member will be
3999 set to the first argument passed to this function to initialize its `soap`
4000 pointer member.
4001
4002 - `T * soap_dup_T(struct soap*, T *dst, const T *src)` (requires <b>`soapcpp2 -Ec`</b>)
4003 deep copy `src` into `dst`, replicating all deep cycles and shared pointers
4004 when a managing `soap` context is provided as argument. When `dst` is NULL,
4005 allocates space for `dst` and returns a pointer to the allocated copy. Deep
4006 copy results in a tree when the `soap` context is NULL, but the presence of
4007 deep cycles will lead to non-termination. Use flag `SOAP_XML_TREE` with
4008 managing context to copy into a tree without cycles and pointers to shared
4009 objects. Returns `dst` or allocated copy when `dst` is NULL.
4010
4011 - `void soap_del_T(const T*)` (requires <b>`soapcpp2 -Ed`</b>) deletes all
4012 heap-allocated members of this object by deep deletion ONLY IF this object
4013 and all of its (deep) members are not managed by a `soap` context AND the deep
4014 structure is a tree (no cycles and co-referenced objects by way of multiple
4015 (non-smart) pointers pointing to the same data). Can be safely used after
4016 `T * soap_dup_T(NULL, NULL, const T*)` to delete the deep copy returned.
4017 Does not delete the object itself.
4018
4019 When in C++ mode, soapcpp2 tool adds several methods to classes in addition to
4020 adding a default constructor and destructor (when these were not explicitly
4021 declared).
4022
4023 The public methods added to a class `T`:
4024
4025 - `virtual int T::soap_type(void)` returns a unique type ID (`SOAP_TYPE_T`).
4026 This numeric ID can be used to distinguish base from derived instances.
4027
4028 - `virtual void T::soap_default(struct soap*)` sets all data members to
4029 default values. If class `T` has a `soap` pointer member to a `::soap`
4030 context then this pointer member will be set to the argument passed to this
4031 function to initialize its `soap` pointer member.
4032
4033 - `virtual void T::soap_serialize(struct soap*) const` serializes object to
4034 prepare for SOAP 1.1/1.2 encoded output (or with `SOAP_XML_GRAPH`) by
4035 analyzing its (cyclic) structures.
4036
4037 - `virtual int T::soap_put(struct soap*, const char *tag, const char *type) const`
4038 emits object in XML, compliant with SOAP 1.1 encoding style, return error
4039 code or `SOAP_OK`. Requires `soap_begin_send(soap)` and
4040 `soap_end_send(soap)`.
4041
4042 - `virtual int T::soap_out(struct soap*, const char *tag, int id, const char *type) const`
4043 emits object in XML, with tag and optional id attribute and <i>`xsi:type`</i>,
4044 return error code or `SOAP_OK`. Requires `soap_begin_send(soap)` and
4045 `soap_end_send(soap)`.
4046
4047 - `virtual void * T::soap_get(struct soap*, const char *tag, const char *type)`
4048 Get object from XML, compliant with SOAP 1.1 encoding style, return pointer
4049 to object or NULL on error. Requires `soap_begin_recv(soap)` and
4050 `soap_end_recv(soap)`.
4051
4052 - `virtual void *soap_in(struct soap*, const char *tag, const char *type)`
4053 Get object from XML, with matching tag and type (NULL matches any tag and
4054 type), return pointer to object or NULL on error. Requires
4055 `soap_begin_recv(soap)` and `soap_end_recv(soap)`
4056
4057 - `virtual T * T::soap_alloc(void) const` returns a new object of type `T`,
4058 default initialized and not managed by a `soap` context.
4059
4060 - `virtual T * T::soap_dup(struct soap*) const` (requires <b>`soapcpp2 -Ec`</b>)
4061 returns a duplicate of this object by deep copying, replicating all deep
4062 cycles and shared pointers when a managing `soap` context is provided as
4063 argument. Deep copy is a tree when argument is NULL, but the presence of
4064 deep cycles will lead to non-termination. Use flag `SOAP_XML_TREE` with the
4065 managing context to copy into a tree without cycles and pointers to shared
4066 objects.
4067
4068 - `virtual void T::soap_del() const` (rquires <b>`soapcpp2 -Ed`</b>) deletes all
4069 heap-allocated members of this object by deep deletion ONLY IF this object
4070 and all of its (deep) members are not managed by a `soap` context AND the deep
4071 structure is a tree (no cycles and co-referenced objects by way of multiple
4072 (non-smart) pointers pointing to the same data). Can be safely used after
4073 `soap_dup(NULL)` to delete the deep copy. Does not delete the object itself.
4074
4075 Also, there are four variations of `soap_new_T` for
4076 class/struct/template type `T` that soapcpp2 auto-generates to create instances
4077 on a context-managed heap:
4078
4079 - `T * soap_new_T(struct soap*)` returns a new instance of `T` with default data
4080 member initializations that are set with the soapcpp2 auto-generated `void
4081 T::soap_default(struct soap*)` method), but ONLY IF the soapcpp2
4082 auto-generated default constructor is used that invokes `soap_default()` and
4083 was not replaced by a user-defined default constructor.
4084
4085 - `T * soap_new_T(struct soap*, int n)` returns an array of `n` new instances of
4086 `T`. Similar to the above, instances are initialized.
4087
4088 - `T * soap_new_req_T(struct soap*, ...)` returns a new instance of `T` and sets
4089 the required data members to the values specified in `...`. The required data
4090 members are those with nonzero minOccurs, see the subsections on
4091 [(smart) pointer members and their occurrence constraints](#toxsd9-8) and
4092 [container and array members and their occurrence constraints](#toxsd9-9).
4093
4094 - `T * soap_new_set_T(struct soap*, ...)` returns a new instance of `T` and sets
4095 the public/serializable data members to the values specified in `...`.
4096
4097 The above functions can be invoked with a NULL `soap` context, but we will be
4098 responsible to use `delete T` to remove this instance from the unmanaged heap.
4099
4100 The allocation functions return NULL when memory allocation failed.
4101
4102 🔝 [Back to table of contents](#)
4103
4104 Special classes and structs {#toxsd10}
4105 ---------------------------
4106
4107 The following applies to both structs and classes. The examples show classes
4108 in C++. For C, use structs and omit the C++ features. Structs also require
4109 the use of the `struct` keyword, otherwise soapcpp2 will throw a syntax error.
4110
4111 ### SOAP-encoded arrays {#toxsd10-1}
4112
4113 A class or struct with the following layout is a one-dimensional SOAP-encoded
4114 array type:
4115
4116 ~~~{.cpp}
4117 class ArrayOfT
4118 {
4119 public:
4120 T *__ptr; // array pointer
4121 int __size; // array size
4122 };
4123 ~~~
4124
4125 where `T` is the array element type. A multidimensional SOAP Array is:
4126
4127 ~~~{.cpp}
4128 class ArrayOfT
4129 {
4130 public:
4131 T *__ptr; // array pointer
4132 int __size[N]; // array size of each dimension
4133 };
4134 ~~~
4135
4136 where `N` is the constant number of dimensions. The pointer points to an array
4137 of `__size[0]*__size[1]* ... * __size[N-1]` elements.
4138
4139 This maps to a complexType restriction of SOAP-ENC:Array in the
4140 soapcpp2-generated XML schema:
4141
4142 <div class="alt">
4143 ~~~{.xml}
4144 <complexType name="ArrayOfT">
4145 <complexContent>
4146 <restriction base="SOAP-ENC:Array">
4147 <sequence>
4148 <element name="item" type="T" minOccurs="0" maxOccurs="unbounded" nillable="true"/>
4149 </sequence>
4150 <attribute ref="SOAP-ENC:arrayType" WSDL:arrayType="ArrayOfT[]"/>
4151 </restriction>
4152 </complexContent>
4153 </complexType>
4154 ~~~
4155 </div>
4156
4157 The name of the class can be arbitrary. We often use `ArrayOfT` without a
4158 prefix to distinguish arrays from other classes and structs.
4159
4160 With SOAP 1.1 encoding, an optional offset member can be added that controls
4161 the start of the index range for each dimension:
4162
4163 ~~~{.cpp}
4164 class ArrayOfT
4165 {
4166 public:
4167 T *__ptr; // array pointer
4168 int __size[N]; // array size of each dimension
4169 int __offset[N]; // array offsets to start each dimension
4170 };
4171 ~~~
4172
4173 For example, we can define a matrix of floats as follows:
4174
4175 ~~~{.cpp}
4176 class Matrix
4177 {
4178 public:
4179 double *__ptr;
4180 int __size[2];
4181 };
4182 ~~~
4183
4184 The following code populates the matrix and serializes it in XML:
4185
4186 ~~~{.cpp}
4187 soap *soap = soap_new1(SOAP_XML_INDENT);
4188 Matrix A;
4189 double a[6] = { 1, 2, 3, 4, 5, 6 };
4190 A.__ptr = a;
4191 A.__size[0] = 2;
4192 A.__size[1] = 3;
4193 soap_write_Matrix(soap, &A);
4194 ~~~
4195
4196 Matrix A is serialized as an array with 2x3 values:
4197
4198 <div class="alt">
4199 ~~~{.xml}
4200 <SOAP-ENC:Array SOAP-ENC:arrayType="xsd:double[2,3]" ...>
4201 <item>1</item>
4202 <item>2</item>
4203 <item>3</item>
4204 <item>4</item>
4205 <item>5</item>
4206 <item>6</item>
4207 </SOAP-ENC:Array>
4208 ~~~
4209 </div>
4210
4211 🔝 [Back to table of contents](#)
4212
4213 ### XSD hexBinary and base64Binary types {#toxsd10-2}
4214
4215 A special case of a one-dimensional array is used to define <i>`xsd:hexBinary`</i> and
4216 <i>`xsd:base64Binary`</i> types when the pointer type is `unsigned char`:
4217
4218 ~~~{.cpp}
4219 class xsd__hexBinary
4220 {
4221 public:
4222 unsigned char *__ptr; // points to raw binary data
4223 int __size; // size of data
4224 };
4225 ~~~
4226
4227 and
4228
4229 ~~~{.cpp}
4230 class xsd__base64Binary
4231 {
4232 public:
4233 unsigned char *__ptr; // points to raw binary data
4234 int __size; // size of data
4235 };
4236 ~~~
4237
4238 To create a new binary type, use either one of the following three forms that
4239 declare a new `ns__binary` type that is a <i>`simpleType`</i> restriction of
4240 <i>`xsd:base64Binary`</i>:
4241
4242 ~~~{.cpp}
4243 typedef xsd__base64Binary ns__binary;
4244 ~~~
4245 ~~~{.cpp}
4246 class ns__binary : public xsd__base64Binary
4247 {
4248 ... // attribute members (@) and class methods
4249 };
4250 ~~~
4251 ~~~{.cpp}
4252 class ns__binary
4253 {
4254 public:
4255 unsigned char *__ptr; // points to raw binary data
4256 int __size; // size of data
4257 ... // attribute members (@) and class methods (optional)
4258 };
4259 ~~~
4260
4261 Here, `xsd__base64Binary` is reused in the first two cases, where
4262 `xsd__base64Binary` is declared as shown above.
4263
4264 @see [DIME/MIME/MTOM attachment binary types](#toxsd10-3)
4265
4266 🔝 [Back to table of contents](#)
4267
4268 ### DIME/MIME/MTOM attachment binary types {#toxsd10-3}
4269
4270 A class or struct with a binary content layout can be extended to support
4271 attachments. The following struct or class type can be used as DIME, MIME, and
4272 MTOM attachment and also be used for <i>`xsd:base64Binary`</i> type values:
4273
4274 ~~~{.cpp}
4275 class xsd__base64Binary
4276 {
4277 public:
4278 unsigned char *__ptr; // points to raw binary data
4279 int __size; // size of data
4280 char *id; // NULL to generate an id, or set to a unique UUID
4281 char *type; // MIME type of the data
4282 char *options; // optional description of MIME attachment
4283 };
4284 ~~~
4285
4286 When the `id`, `type`, or `options` members are non-NULL, an attachment will be
4287 used instead of base64 XML content. DIME attachments are the default. To
4288 switch to MIME use the `SOAP_ENC_MIME` context flag. To switch to MTOM use the
4289 `SOAP_ENC_MTOM` context flag.
4290
4291 MTOM is typically used with XOP <i>`<xop:Include>`</i> elements, which is
4292 preferred and declared as follows:
4293
4294 ~~~{.cpp}
4295 //gsoap xop schema import: http://www.w3.org/2004/08/xop/include
4296 class _xop__Include
4297 {
4298 public:
4299 unsigned char *__ptr; // points to raw binary data
4300 int __size; // size of data
4301 char *id; // NULL to generate an id, or set to a unique UUID
4302 char *type; // MIME type of the data
4303 char *options; // optional description of MIME attachment
4304 };
4305 ~~~
4306
4307 Attachments are beyond the scope of this article. See the
4308 [gSOAP user guide.](../../guide/html/index.html) for more details.
4309
4310 🔝 [Back to table of contents](#)
4311
4312 ### Wrapper class/struct with simpleContent {#toxsd10-4}
4313
4314 A class or struct with the following layout is a complexType that wraps
4315 simpleContent:
4316
4317 ~~~{.cpp}
4318 class ns__simple
4319 {
4320 public:
4321 T __item; // primitive type for the simpleContent
4322 ... // attribute members (@) and class methods (optional)
4323 };
4324 ~~~
4325
4326 The type `T` is a primitive type (`bool`, `enum`, `time_t`, numeric and string
4327 types), `xsd__hexBinary`, `xsd__base64Binary`, and custom serializers, such as
4328 `xsd__dateTime`.
4329
4330 This maps to a complexType with simpleContent in the soapcpp2-generated XML
4331 schema:
4332
4333 <div class="alt">
4334 ~~~{.xml}
4335 <complexType name="simple">
4336 <simpleContent>
4337 <extension base="T"/>
4338 </simpleContent>
4339 </complexType>
4340 ~~~
4341 </div>
4342
4343 A wrapper class/struct may include any number of members that are declared as
4344 attributes with `@`, which should be placed after the `__item` member.
4345
4346 🔝 [Back to table of contents](#)
4347
4348 ### DOM anyType and anyAttribute {#toxsd10-5}
4349
4350 Use of a DOM is optional and enabled by `#import "dom.h"` to use the DOM
4351 `xsd__anyType` element node and `xsd__anyAttribute` attribute node:
4352
4353 ~~~{.cpp}
4354 #import "dom.h"
4355
4356 class ns__record
4357 {
4358 public:
4359 @ xsd__anyAttribute attributes; // optional DOM attributes
4360 xsd__anyType *name; // optional DOM element (pointer means minOccurs=0)
4361 xsd__anyType address; // required DOM element (minOccurs=1)
4362 xsd__anyType email 0; // optional DOM element (minOccurs=0)
4363 ... // other members
4364 };
4365 ~~~
4366
4367 where `name` contains XML stored in a DOM node set and `attributes` is a list
4368 of all visibly rendered attributes. The name `attributes` is arbitrary and any
4369 name will suffice.
4370
4371 You should place the `xsd__anyType` members at the end of the struct or class.
4372 This ensures that the DOM members are populated last as a "catch all". A
4373 member name starting with double underscore is a wildcard member. These
4374 members are placed at the end of a struct or class automatically by soapcpp2.
4375
4376 An `#import "dom.h"` import is automatically added by <b>`wsdl2h -d`</b> with
4377 option <b>`-d`</b> to bind <i>`xsd:anyType`</i> to DOM nodes, and also to
4378 populate <i>`xsd:any`</i>, <i>`xsd:anyAttribute`</i> and <i>`xsd:mixed`</i> XML
4379 content:
4380
4381 ~~~{.cpp}
4382 #import "dom.h"
4383
4384 class ns__record
4385 {
4386 public:
4387 @ xsd__anyAttribute __anyAttribute; // optional DOM attributes
4388 std::vector<xsd__anyType> __any 0; // optional DOM elements (minOccurs=0)
4389 xsd__anyType __mixed 0; // optional mixed content (minOccurs=0)
4390 ... // other members
4391 };
4392 ~~~
4393
4394 where the members prefixed with `__` are "invisible" to the XML parser, meaning
4395 that these members are not bound to XML tag names.
4396
4397 In C you can use a dynamic arrary instead of `std::vector`:
4398
4399 ~~~{.cpp}
4400 #import "dom.h"
4401
4402 struct ns__record
4403 {
4404 @ xsd__anyAttribute __anyAttribute; // optional DOM attributes
4405 $ int __sizeOfany; // size of the array
4406 xsd__anyType *__any; // optional DOM elements (pointer means minOccurs=0)
4407 xsd__anyType __mixed 0; // optional mixed content (minOccurs=0)
4408 ... // other members
4409 };
4410 ~~~
4411
4412 Classes can inherit DOM, which enables full use of polymorphism with one base
4413 DOM class:
4414
4415 ~~~{.cpp}
4416 #import "dom.h"
4417
4418 class ns__record : public xsd__anyType
4419 {
4420 public:
4421 std::vector<xsd__anyType*> array; // array of objects of any class
4422 ... // other members
4423 };
4424 ~~~
4425
4426 This permits an `xsd__anyType` pointer to refer to a derived class such as
4427 `ns__record`, which will be serialized with an <i>`xsi:type`</i> attribute that is
4428 set to "ns:record". The <i>`xsi:type`</i> attributes add the necessary type information
4429 to distinguish the XML content from the DOM base type. This is important for
4430 the receiving end: without <i>`xsd:type`</i> attributes with type names, only base DOM
4431 objects are recognized and instantiated.
4432
4433 Because C lacks object-oriented programming concepts such as class inheritance
4434 and polymorphism, you should consider using [derived types in C and C++](#toxsd9-1-1).
4435
4436 An alternative is to use the special [tagged void pointer members](#toxsd9-12)
4437 to serialize data pointed to by a `void*` member, which can be any serializable
4438 type, such as derived types. This approach uses <i>`xsi:type`</i> attributes
4439 to identify the type of value serialized.
4440
4441 To ensure that wsdl2h generates pointer-based `xsd__anyType` DOM nodes with
4442 <b>`wsdl2h -d`</b> using option <b>`-d`</b> for <i>`xsd:any`</i>, add the
4443 following line to <i>`typemap.dat`</i>:
4444
4445 xsd__any = | xsd__anyType*
4446
4447 This lets wsdl2h produce class/struct members and containers with
4448 `xsd__anyType*` for <i>`xsd:any`</i> instead of `xsd__anyType`. To just force all
4449 <i>`xsd:anyType`</i> uses to be pointer-based, declare in <i>`typemap.dat`</i>:
4450
4451 xsd__anyType = | xsd__anyType*
4452
4453 If you use <b>`wsdl2h -d -p`</b> using options <b>`-d`</b> and <b>`-p`</b> then
4454 every class will inherit DOM as shown above. Without option `-d`, an
4455 `xsd__anyType` type is generated to serve as the root type in the type
4456 hierarchy:
4457
4458 ~~~{.cpp}
4459 class xsd__anyType { _XML __item; struct soap *soap; };
4460
4461 class ns__record : public xsd__anyType
4462 {
4463 ...
4464 };
4465 ~~~
4466
4467 where the `_XML __item` member holds any XML content as a literal XML string.
4468
4469 To use the DOM API, compile <i>`dom.c`</i> (or <i>`dom.cpp`</i> for C++), or
4470 link the gSOAP library with <b>`-lgsoapssl`</b> (or <b>`-lgsoapssl++`</b> for C++).
4471
4472 @see Documentation of [XML DOM and XPath](http://www.genivia.com/doc/dom/html)
4473 for more details.
4474
4475 🔝 [Back to table of contents](#)
4476
4477 Directives {#directives}
4478 ==========
4479
4480 You can use `//gsoap` directives in the interface header file with the data
4481 binding interface for soapcpp2. These directives are used to configure the
4482 code generated by soapcpp2 by declaring various. properties of Web services
4483 and XML schemas. When using the wsdl2h tool, you will notice that wsdl2h
4484 generates directives automatically based on the WSDL and XSD input.
4485
4486 Service directives are applicable to service and operations described by WSDL.
4487 Schema directives are applicable to types, elements, and attributes defined by
4488 XML schemas.
4489
4490 🔝 [Back to table of contents](#)
4491
4492 Service directives {#directives-1}
4493 ------------------
4494
4495 A service directive must start at a new line and is of the form:
4496
4497 ~~~{.cpp}
4498 //gsoap <prefix> service <property>: <value>
4499 ~~~
4500
4501 where `<prefix>` is the XML namespace prefix of a service binding. The
4502 `<property>` and `<value>` fields are one of the following:
4503
4504 property | value
4505 --------------- | -----
4506 `name` | name of the service, optionally followed by text describing the service
4507 `namespace` | URI of the WSDL targetNamespace
4508 `documentation` | text describing the service (see also the `name` property), multiple permitted
4509 `doc` | an alias for the `documentation` property
4510 `style` | `document` (default) SOAP messaging style or `rpc` for SOAP RPC
4511 `encoding` | `literal` (default), `encoded` for SOAP encoding, or a custom URI
4512 `protocol` | specifies SOAP or REST, see below
4513 `port` | URL of the service endpoint, usually an http or https address, to use in the WSDL definitions/service/port/address/\@location
4514 `location` | an alias for the `port` property
4515 `endpoint` | an alias for the `port` property
4516 `transport` | URI declaration of the transport, usually `http://schemas.xmlsoap.org/soap/http`
4517 `definitions` | name of the WSDL definitions/\@name
4518 `type` | name of the WSDL definitions/portType/\@name (WSDL2.0 interface/\@name)
4519 `portType` | an alias for the `type` property (`portType` follows SOAP 1.1 naming conventions)
4520 `interface` | an alias for the `type` property (`interface` follows SOAP 1.2 naming conventions)
4521 `binding` | name of the WSDL definitions/binding/\@name
4522 `portName` | name of the WSDL definitions/service/port/\@name
4523 `executable` | name of the "executable" to use in the WSDL definitions/service/port/address/\@location
4524
4525 The service `name` and `namespace` properties are required in order to generate
4526 a valid WSDL with soapcpp2. The other properties are optional.
4527
4528 The `style` and `encoding` property defaults are changed with
4529 <b>`soapcpp2 -e`</b> option <b>`-e`</b> to `rpc` and `encoded`, respectively.
4530
4531 The `protocol` property is `SOAP` by default (SOAP 1.1). Protocol property
4532 values are:
4533
4534 protocol value | description
4535 -------------- | -----------
4536 `SOAP` | SOAP transport, supporting both SOAP 1.1 and 1.2
4537 `SOAP1.1` | SOAP 1.1 transport (same as `soapcpp2 -1`)
4538 `SOAP1.2` | SOAP 1.2 transport (same as `soapcpp2 -2`)
4539 `SOAP-GET` | one-way SOAP 1.1 or 1.2 with HTTP GET
4540 `SOAP1.1-GET` | one-way SOAP 1.1 with HTTP GET
4541 `SOAP1.2-GET` | one-way SOAP 1.2 with HTTP GET
4542 `HTTP` | non-SOAP REST protocol with HTTP POST
4543 `POST` | non-SOAP REST protocol with HTTP POST
4544 `GET` | non-SOAP REST protocol with HTTP GET
4545 `PUT` | non-SOAP REST protocol with HTTP PUT
4546 `DELETE` | non-SOAP REST protocol with HTTP DELETE
4547
4548 You can bind service operations to the WSDL namespace of a service by using the
4549 namespace prefix as part of the identifier name of the function that defines
4550 the service operation:
4551
4552 ~~~{.cpp}
4553 int prefix__func(arg1, arg2, ..., argn, result);
4554 ~~~
4555
4556 You can override the `port` endpoint URL at runtime in the auto-generated
4557 `soap_call_prefix__func` service call (C/C++ client side) and in the C++ proxy
4558 class service call.
4559
4560 🔝 [Back to table of contents](#)
4561
4562 Service method directives {#directives-2}
4563 -------------------------
4564
4565 Service properties are applicable to a service and to all of its operations.
4566 Service method directives are specifically applicable to a service operation.
4567
4568 A service method directive is of the form:
4569
4570 ~~~{.cpp}
4571 //gsoap <prefix> service method-<property>: <method> <value>
4572 ~~~
4573
4574 where `<prefix>` is the XML namespace prefix of a service binding and
4575 `<method>` is the unqualified name of a service operation. The `<property>`
4576 and `<value>` fields are one of the following:
4577
4578 method property | value
4579 --------------------------- | -----
4580 `method-documentation` | text describing the service operation
4581 `method` | an alias for the `method-documentation` property
4582 `method-action` | `""` or URI SOAPAction HTTP header, or URL query string for REST protocols
4583 `method-input-action` | `""` or URI SOAPAction HTTP header of service request messages
4584 `method-output-action` | `""` or URI SOAPAction HTTP header of service response messages
4585 `method-fault-action` | `""` or URI SOAPAction HTTP header of service fault messages
4586 `method-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Header
4587 `method-input-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Headers of requests
4588 `method-output-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Headers of responses
4589 `method-fault` | type name of a struct or class member used in `SOAP_ENV__Details` struct
4590 `method-mime-type` | REST content type or SOAP MIME attachment content type(s)
4591 `method-input-mime-type` | REST content type or SOAP MIME attachment content type(s) of request message
4592 `method-output-mime-type` | REST content type or SOAP MIME attachment content type(s) of response message
4593 `method-style` | `document` or `rpc`
4594 `method-encoding` | `literal`, `encoded`, or a custom URI for encodingStyle of messages
4595 `method-response-encoding` | `literal`, `encoded`, or a custom URI for encodingStyle of response messages
4596 `method-protocol` | SOAP or REST, see [service directives](#directives-1)
4597
4598 The `method-header-part` properties can be repeated for a service operation to
4599 declare multiple SOAP Header parts that the service operation requires. You
4600 can use `method-input-header-part` and `method-output-header-part` to
4601 differentiate between request and response messages.
4602
4603 The `method-fault` property can be repeated for a service operation to declare
4604 multiple faults that the service operation may return.
4605
4606 The `method-action` property serves two purposes:
4607
4608 -# To set the SOAPAction header for SOAP protocols, i.e. sets the
4609 definitions/binding/operation/SOAP:operation/\@soapAction.
4610
4611 -# To set the URL query string for endpoints with REST protocols, i.e. sets the
4612 definitions/binding/operation/HTTP:operation/\@location, which specifies
4613 a URL query string (starts with a `?`) to complete the service endpoint URL
4614 or extends the endpoint URL with a local path (starts with a `/`).
4615
4616 Use `method-input-action` and `method-output-action` to differentiate the
4617 SOAPAction between SOAP request and response messages.
4618
4619 You can always override the port endpoint URL and action values at runtime in
4620 the auto-generated `soap_call_prefix__func` service call (C/C++ client side)
4621 and in the auto-generated C++ proxy class service calls. A runtime NULL
4622 endpoint URL and/or action uses the defaults set by these directives.
4623
4624 The `method-mime-type` property serves two purposes:
4625
4626 -# To set the type of MIME/MTOM attachments used with SOAP protocols. Multiple
4627 attachment types can be declared for a SOAP service operation, i.e. adds
4628 definitions/binding/operation/input/MIME:multipartRelated/MIME:part/MIME:content/\@type
4629 for each type specified.
4630
4631 -# To set the MIME type of a REST operation. This replaces XML declared in
4632 WSDL by definitions/binding/operation/(input|output)/MIME:mimeXml with
4633 MIME:content/\@type. Use `application/x-www-form-urlencoded` with REST POST
4634 and PUT protocols to send encoded form data automatically instead of XML.
4635 Only primitive type values can be transmitted with form data, such as
4636 numbers and strings, i.e. only types that are legal to use as
4637 [attributes members](#toxsd9-5).
4638
4639 Use `method-input-mime-type` and `method-output-mime-type` to differentiate the
4640 attachment types between request and response messages.
4641
4642 🔝 [Back to table of contents](#)
4643
4644 Schema directives {#directives-3}
4645 -----------------
4646
4647 A schema directive is of the form:
4648
4649 ~~~{.cpp}
4650 //gsoap <prefix> schema <property>: <value>
4651 ~~~
4652
4653 where `<prefix>` is the XML namespace prefix of a schema. The `<property>` and
4654 `<value>` fields are one of the following:
4655
4656 property | value
4657 --------------- | -----
4658 `namespace` | URI of the XSD targetNamespace
4659 `namespace2` | alternate URI pattern for the XSD namespace (i.e. URI is also accepted by the XML parser)
4660 `import` | URI of an imported namespace, as an alternative or in addition to `namespace`, adds `xsd:import` to the generated WSDL and XSD files
4661 `form` | `unqualified` (default) or `qualified` local element and attribute form defaults
4662 `elementForm` | `unqualified` (default) or `qualified` local element form default
4663 `attributeForm` | `unqualified` (default) or `qualified` local attribute form default
4664 `typed` | `no` (default) or `yes` for serializers to add `xsi:type` attributes to XML
4665
4666 To learn more about the local form defaults, see [qualified and unqualified members.](#toxsd9-6)
4667
4668 The `namespace2` URI is a pattern with `*` matching any sequence of characters
4669 and `-` matching any character. This pattern instructs the XML parser and validator
4670 to also accept the URI pattern as a valid namespace for the specified `<prefix>`.
4671
4672 The `typed` property is implicitly `yes` when <b>`soapcpp2 -t`</b> option <b>`-t`</b> is used.
4673
4674 🔝 [Back to table of contents](#)
4675
4676 Schema type directives {#directives-4}
4677 ----------------------
4678
4679 A schema type directive is of the form:
4680
4681 ~~~{.cpp}
4682 //gsoap <prefix> schema type-<property>: <name> <value>
4683 //gsoap <prefix> schema type-<property>: <name>::<member> <value>
4684 ~~~
4685
4686 where `<prefix>` is the XML namespace prefix of a schema and `<name>` is an
4687 unqualified name of a C/C++ type, and the optional `<member>` is a class/struct
4688 members or enum constant.
4689
4690 You can describe a type with one of the following:
4691
4692 type property | value
4693 -------------------- | -----
4694 `type-documentation` | text describing the schema type
4695 `type` | an alias for the `type-documentation` property
4696
4697 For example, you can add a description to an enumeration:
4698
4699 ~~~{.cpp}
4700 //gsoap ns schema type: Vowels The letters A, E, I, O, U, and sometimes Y
4701 //gsoap ns schema type: Vowels::Y A vowel, sometimes
4702 enum class ns__Vowels : char { A = 'A', E = 'E', I = 'I', O = 'O', U = 'U', Y = 'Y' };
4703 ~~~
4704
4705 This documented enumeration maps to a simpleType restriction of <i>`xsd:string`</i> in
4706 the soapcpp2-generated schema:
4707
4708 <div class="alt">
4709 ~~~{.xml}
4710 <simpleType name="Vowels">
4711 <annotation>
4712 <documentation>The letters A, E, I, O, U, and sometimes Y</documentation>
4713 </annotation>
4714 <restriction base="xsd:string">
4715 <enumeration value="A"/>
4716 <enumeration value="E"/>
4717 <enumeration value="I"/>
4718 <enumeration value="O"/>
4719 <enumeration value="U"/>
4720 <enumeration value="Y">
4721 <annotation>
4722 <documentation>A vowel, sometimes</documentation>
4723 </annotation>
4724 <enumeration/>
4725 </restriction>
4726 </simpleType>
4727 ~~~
4728 </div>
4729
4730 🔝 [Back to table of contents](#)
4731
4732 Serialization rules {#rules}
4733 ===================
4734
4735 A presentation on XML data bindings is not complete without discussing the
4736 serialization rules and options that put your data in XML on the wire or store
4737 it a file or buffer.
4738
4739 There are several options to choose from to serialize data in XML. The choice
4740 depends on the use of the SOAP protocol or if SOAP is not required. The wsdl2h
4741 tool automates this for you by taking the WSDL transport bindings into account
4742 when generating the service functions in C and C++ that use SOAP or REST.
4743
4744 The gSOAP tools are not limited to SOAP. The tools implement generic XML data
4745 bindings for SOAP, REST, and other uses of XML. So you can read and write XML
4746 using the serializing [operations on classes and structs](#toxsd9-14).
4747
4748 The following sections briefly explain the serialization rules with respect to
4749 the SOAP protocol for XML Web services. A basic understanding of the SOAP
4750 protocol is useful when developing client and server applications that must
4751 interoperate with other SOAP applications.
4752
4753 SOAP/REST Web service client and service operations are represented as
4754 functions in your interface header file with the data binding interface for
4755 soapcpp2. The soapcpp2 tool will translate these function to client-side
4756 service invocation calls and server-side service operation dispatchers.
4757
4758 A discussion of SOAP clients and servers is beyond the scope of this article.
4759 However, the SOAP options discussed here also apply to SOAP client and server
4760 development.
4761
4762 🔝 [Back to table of contents](#)
4763
4764 SOAP document versus rpc style {#doc-rpc}
4765 ------------------------------
4766
4767 The `wsdl:binding/soap:binding/@style` attribute in the <i>`<wsdl:binding>`</i>
4768 section of a WSDL is either "document" or "rpc". The "rpc" style refers to
4769 SOAP RPC (Remote Procedure Call), which is more restrictive than the "document"
4770 style by requiring one XML element in the SOAP Body to act as the procedure
4771 name with XML subelements as its parameters.
4772
4773 For example, the following directives in the interface header file for soapcpp2
4774 declare that `DBupdate` is a SOAP RPC encoding service method:
4775
4776 ~~~{.cpp}
4777 //gsoap ns service namespace: urn:DB
4778 //gsoap ns service method-protocol: DBupdate SOAP
4779 //gsoap ns service method-style: DBupdate rpc
4780 int ns__DBupdate(...);
4781 ~~~
4782
4783 The XML payload has a SOAP envelope, optional SOAP header, and a SOAP body with
4784 one element representing the operation with the parameters as subelements:
4785
4786 <div class="alt">
4787 ~~~{.xml}
4788 <SOAP-ENV:Envelope
4789 xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
4790 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
4791 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4792 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4793 xmlsn:ns="urn:DB">
4794 <SOAP-ENV:Body>
4795 <ns:DBupdate>
4796 ...
4797 </ns:DBupdate>
4798 </SOAP-ENV:Body>
4799 </SOAP-ENV:Envelope>
4800 ~~~
4801 </div>
4802
4803 The "document" style puts no restrictions on the SOAP Body content. However, we
4804 recommend that the first element's tag name in the SOAP Body should be unique
4805 to each type of operation, so that the receiver can dispatch the operation
4806 based on this element's tag name. Alternatively, the HTTP URL path can be used
4807 to specify the operation, or the HTTP action header can be used to dispatch
4808 operations automatically on the server side (soapcpp2 options -a and -A).
4809
4810 🔝 [Back to table of contents](#)
4811
4812 SOAP literal versus encoding {#lit-enc}
4813 ----------------------------
4814
4815 The `wsdl:operation/soap:body/@use` attribute in the <i>`<wsdl:binding>`</i> section
4816 of a WSDL is either "literal" or "encoded". The "encoded" use refers to the
4817 SOAP encoding rules that support id-ref multi-referenced elements to serialize
4818 data as graphs.
4819
4820 SOAP encoding is very useful if the data internally forms a graph (including
4821 cycles) and we want the graph to be serialized in XML in a format that ensures
4822 that its structure is preserved. In that case, SOAP 1.2 encoding is the best
4823 option.
4824
4825 SOAP encoding also adds encoding rules for [SOAP arrays](#toxsd10) to serialize
4826 multi-dimensional arrays. The use of XML attributes to exchange XML data in
4827 SOAP encoding is not permitted. The only attributes permitted are the standard
4828 XSD attributes, SOAP encoding attributes (such as for arrays), and id-ref.
4829
4830 For example, the following directives in the interface header file for soapcpp2
4831 declare that `DBupdate` is a SOAP RPC encoding service method:
4832
4833 ~~~{.cpp}
4834 //gsoap ns service namespace: urn:DB
4835 //gsoap ns service method-protocol: DBupdate SOAP
4836 //gsoap ns service method-style: DBupdate rpc
4837 //gsoap ns service method-encoding: DBupdate encoded
4838 int ns__DBupdate(...);
4839 ~~~
4840
4841 The XML payload has a SOAP envelope, optional SOAP header, and a SOAP body with
4842 an encodingStyle attribute for SOAP 1.1 encoding and an element representing the
4843 operation with parameters that are SOAP 1.1 encoded:
4844
4845 <div class="alt">
4846 ~~~{.xml}
4847 <SOAP-ENV:Envelope
4848 xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
4849 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
4850 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4851 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4852 xmlsn:ns="urn:DB">
4853 <SOAP-ENV:Body SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
4854 <ns:DBupdate>
4855 <records SOAP-ENC:arrayType="ns:record[3]">
4856 <item>
4857 <name href="#_1"/>
4858 <SSN>1234567890</SSN>
4859 </item>
4860 <item>
4861 <name>Jane</name>
4862 <SSN>1987654320</SSN>
4863 </item>
4864 <item>
4865 <name href="#_1"/>
4866 <SSN>2345678901</SSN>
4867 </item>
4868 </records>
4869 </ns:DBupdate>
4870 <id id="_1" xsi:type="xsd:string">Joe</id>
4871 </SOAP-ENV:Body>
4872 </SOAP-ENV:Envelope>
4873 ~~~
4874 </div>
4875
4876 In the XML fragment shown above the name "Joe" is shared by two records and the
4877 string is referenced by SOAP 1.1 href and id attributes.
4878
4879 While the soapcpp-generated serializers only introduce multi-referenced
4880 elements in the payload when they are actually multi-referenced in the data
4881 graph, other SOAP applications may render multi-referenced elements more
4882 aggressively. The example could also be rendered as:
4883
4884 <div class="alt">
4885 ~~~{.xml}
4886 <SOAP-ENV:Envelope
4887 xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
4888 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
4889 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4890 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4891 xmlsn:ns="urn:DB">
4892 <SOAP-ENV:Body SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
4893 <ns:DBupdate>
4894 <records SOAP-ENC:arrayType="ns:record[3]">
4895 <item href="#id1"/>
4896 <item href="#id2"/>
4897 <item href="#id3"/>
4898 </records>
4899 </ns:DBupdate>
4900 <id id="id1" xsi:type="ns:record">
4901 <name href="#id4"/>
4902 <SSN>1234567890</SSN>
4903 </id>
4904 <id id="id2" xsi:type="ns:record">
4905 <name href="#id5"/>
4906 <SSN>1987654320</SSN>
4907 </id>
4908 <id id="id3" xsi:type="ns:record">
4909 <name href="#id4"/>
4910 <SSN>2345678901</SSN>
4911 </id>
4912 <id id="id4" xsi:type="xsd:string">Joe</id>
4913 <id id="id5" xsi:type="xsd:string">Jane</id>
4914 </SOAP-ENV:Body>
4915 </SOAP-ENV:Envelope>
4916 ~~~
4917 </div>
4918
4919 SOAP 1.2 encoding is cleaner and produces more accurate XML encodings of data
4920 graphs by setting the id attribute on the element that is referenced:
4921
4922 <div class="alt">
4923 ~~~{.xml}
4924 <SOAP-ENV:Envelope
4925 xmlns:SOAP-ENV="http://www.w3.org/2003/05/soap-envelope"
4926 xmlns:SOAP-ENC="http://www.w3.org/2003/05/soap-encoding"
4927 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4928 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4929 xmlsn:ns="urn:DB">
4930 <SOAP-ENV:Body>
4931 <ns:DBupdate SOAP-ENV:encodingStyle="http://www.w3.org/2003/05/soap-encoding">
4932 <records SOAP-ENC:itemType="ns:record" SOAP-ENC:arraySize="3">
4933 <item>
4934 <name SOAP-ENC:id="_1">Joe</name>
4935 <SSN>1234567890</SSN>
4936 </item>
4937 <item>
4938 <name>Jane</name>
4939 <SSN>1987654320</SSN>
4940 </item>
4941 <item>
4942 <name SOAP-ENC:ref="_1"/>
4943 <SSN>2345678901</SSN>
4944 </item>
4945 </records>
4946 </ns:DBupdate>
4947 </SOAP-ENV:Body>
4948 </SOAP-ENV:Envelope>
4949 ~~~
4950 </div>
4951
4952 @note Some SOAP 1.2 applications consider the namespace `SOAP-ENC` of
4953 <i>`SOAP-ENC:id`</i> and <i>`SOAP-ENC:ref`</i> optional. With gSOAP, the SOAP
4954 1.2 encoding serialization follows the 2007 standard, while accepting
4955 unqualified id and ref attributes.
4956
4957 To remove all rendered id-ref multi-referenced elements, use the
4958 `SOAP_XML_TREE` flag to initialize the `soap` context.
4959
4960 Some XSD validation rules are turned off with SOAP encoding, because of the
4961 presence of additional attributes, such as id and ref/href, SOAP arrays with
4962 arbitrary element tags for array elements, and the occurrence of additional
4963 multi-ref elements in the SOAP 1.1 Body.
4964
4965 The use of "literal" puts no restrictions on the XML in the SOAP Body. Full
4966 XSD validation is possible, which can be enabled with the `SOAP_XML_STRICT`
4967 flag to initialize the `soap` context. However, data graphs will be
4968 serialized as trees and cycles in the data will be cut from the XML rendition.
4969
4970 🔝 [Back to table of contents](#)
4971
4972 SOAP 1.1 versus SOAP 1.2 {#soap}
4973 ------------------------
4974
4975 There are two SOAP protocol versions: 1.1 and 1.2. The gSOAP tools can switch
4976 between the two versions seamlessly. You can declare the default SOAP version
4977 for a service operation as follows:
4978
4979 ~~~{.cpp}
4980 //gsoap ns service method-protocol: DBupdate SOAP1.2
4981 ~~~
4982
4983 Use `SOAP` (SOAP 1.1), `SOAP1.1`, `SOAP1.2`, and `HTTP` to switch SOAP versions
4984 or enable REST methods with HTTP POST. See [service directives](#directives-1)
4985 and [XML serialization](#non-soap).
4986
4987 The soapcpp2 tool auto-generates client and server code. At the client side,
4988 this operation sends data with SOAP 1.2 but accepts responses also in SOAP 1.1.
4989 At the server side, this operation accepts requests in SOAP 1.1 and 1.2 and
4990 will return responses in the same SOAP version.
4991
4992 As we discussed in the previous section, the SOAP 1.2 protocol has a cleaner
4993 multi-referenced element serialization format that greatly enhances the
4994 accuracy of data graph serialization with SOAP RPC encoding and is therefore
4995 recommended.
4996
4997 The SOAP 1.2 protocol default can also be set by importing and loading
4998 <i>`gsoap/import/soap12.h`</i>:
4999
5000 ~~~{.cpp}
5001 #import "soap12.h"
5002 ~~~
5003
5004 Finally, the soapcpp2 tool has options to force SOAP 1.1, SOAP 1.2, or remove
5005 SOAP altogether with <b>`soapcpp2 -1`</b> (SOAP 1.1), <b>`soapcpp2 -2`</b>
5006 (SOAP 1.2) and <b>`soapcpp2 -0`</b> (plain XML, no SOAP).
5007
5008 🔝 [Back to table of contents](#)
5009
5010 XML serialization {#non-soap}
5011 -----------------
5012
5013 You can serialize data to XML that is stored on the heap, on the stack (locals), and
5014 static data as long as the serializable (i.e. non-transient) values are
5015 properly initialized and pointers in the data structures are either NULL or
5016 point to valid structures.
5017
5018 When XML is deserialized into data, the data is put on the heap and managed by the
5019 `::soap` context, see also [memory management](#memory).
5020
5021 You can read and write XML directly to a file or stream with the serializing
5022 [operations on classes and structs](#toxsd9-14).
5023
5024 To define and use XML Web service client and service operations, we can declare
5025 these operations in your interface header file with the data binding interface
5026 for soapcpp2 as functions. The function are translated by soapcpp2 to
5027 client-side service invocation calls and server-side service operation
5028 dispatchers.
5029
5030 The REST operations POST, GET, and PUT are declared with `//gsoap` directives
5031 in the interface header file for soapcpp2. For example, a REST HTTP POST
5032 operation is declared as follows:
5033
5034 ~~~{.cpp}
5035 //gsoap ns service namespace: urn:DB
5036 //gsoap ns service method-protocol: DBupdate POST
5037 int ns__DBupdate(...);
5038 ~~~
5039
5040 There are no SOAP Envelope and SOAP Body elements in the payload for
5041 `DBupdate`. Also the XML serialization rules are identical to SOAP
5042 document/literal, meaning no SOAP RPC encoding XML structures are implicitly
5043 used. The XML payload only has the operation name as an element with its
5044 parameters serialized as subelements:
5045
5046 <div class="alt">
5047 ~~~{.xml}
5048 <ns:DBupdate xmln:ns="urn:DB" ...>
5049 ...
5050 </ns:DBupdate>
5051 ~~~
5052 </div>
5053
5054 To force id-ref serialization with REST similar to SOAP 1.2 multi-reference
5055 encoding, use the `SOAP_XML_GRAPH` flag to initialize the `soap` context.
5056 The XML serialization includes id and ref attributes for multi-referenced
5057 elements as follows:
5058
5059 <div class="alt">
5060 ~~~{.xml}
5061 <ns:DBupdate xmln:ns="urn:DB" ...>
5062 <records>
5063 <item>
5064 <name id="_1">Joe</name>
5065 <SSN>1234567890</SSN>
5066 </item>
5067 <item>
5068 <name>Jane</name>
5069 <SSN>1987654320</SSN>
5070 </item>
5071 <item>
5072 <name ref="_1"/>
5073 <SSN>2345678901</SSN>
5074 </item>
5075 </records>
5076 </ns:DBupdate>
5077 ~~~
5078 </div>
5079
5080 🔝 [Back to table of contents](#)
5081
5082 Input and output {#io}
5083 ================
5084
5085 Reading and writing XML from/to files, streams and string buffers is done via
5086 the managing `soap` context by setting one of the following context variables that
5087 control IO sources and sinks:
5088
5089 ~~~{.cpp}
5090 soap->recvfd = fd; // an int file descriptor to read from (0 by default)
5091 soap->sendfd = fd; // an int file descriptor to write to (1 by default)
5092 soap->is = &is; // C++ only: a std::istream is object to read from
5093 soap->os = &os; // C++ only: a std::ostream os object to write to
5094 soap->is = cs; // C only: a const char* string to read from (soap->is will advance)
5095 soap->os = &cs; // C only: pointer to a const char*, will be set to point to the string output
5096 ~~~
5097
5098 Normally, all of these context variables are NULL, which is required to send and
5099 receive data over sockets by gSOAP client and server applications. Therefore,
5100 if you set any of these context variables in a client or server application
5101 then you should reset them to NULL to ensure that socket communications are not
5102 blocked.
5103
5104 @note The use of `soap::is` and `soap::os` in C requires gSOAP 2.8.28 or greater.
5105
5106 In the following sections, we present more details on how to read and write to
5107 files and streams, and use string buffers as sources and sinks for XML data.
5108
5109 In addition, you can set IO callback functions to handle IO at a lower level.
5110 For more details on defining your own callback functions, see the
5111 [gSOAP user guide.](../../guide/html/index.html)
5112
5113 🔝 [Back to table of contents](#)
5114
5115 Reading and writing from/to files and streams {#io1}
5116 ---------------------------------------------
5117
5118 The default IO is standard input and output. Other sources and sinks (those
5119 listed above) will be used until you (re)set them. For example with file-based
5120 input and output:
5121
5122 ~~~{.cpp}
5123 FILE *fp = fopen("record.xml", "r");
5124 if (fp != NULL)
5125 {
5126 soap->recvfd = fileno(fp); // get file descriptor of file to read from
5127 if (soap_read_ns__record(soap, &pers1))
5128 ... // handle IO error
5129 fclose(fp);
5130 soap->recvfd = 0; // read from stdin, or -1 to block reading
5131 }
5132
5133 FILE *fp = fopen("record.xml", "w");
5134 if (fp != NULL)
5135 {
5136 soap->sendfd = fileno(fp); // get file descriptor of file to write to
5137 if (soap_write_ns__record(soap, &pers1))
5138 ... // handle IO error
5139 fclose(fp);
5140 soap->sendfd = 1; // write to stdout, or -1 to block writing
5141 }
5142 ~~~
5143
5144 Similar code with streams in C++:
5145
5146 ~~~{.cpp}
5147 #include <fstream>
5148
5149 std::fstream fs;
5150 fs.open("record.xml", std::ios::in);
5151 if (fs)
5152 {
5153 soap->is = &fs;
5154 if (soap_read__ns__record(soap, &pers1))
5155 ... // handle IO error
5156 fs.close();
5157 soap->is = NULL;
5158 }
5159
5160 fs.open("record.xml", std::ios::out);
5161 if (fs)
5162 {
5163 soap->os = &fs;
5164 if (soap_write__ns__record(soap, &pers1))
5165 ... // handle IO error
5166 fs.close();
5167 soap->os = NULL;
5168 }
5169 ~~~
5170
5171 🔝 [Back to table of contents](#)
5172
5173 Reading and writing from/to string buffers {#io2}
5174 ------------------------------------------
5175
5176 For C++ we recommend to use `std::stringstream` objects from the
5177 <i>`sstream`</i> C++ library as illustrated in the following example:
5178
5179 ~~~{.cpp}
5180 #include <sstream>
5181
5182 std::stringstream ss;
5183 ss.str("..."); // XML to parse
5184 soap->is = &ss;
5185 if (soap_read__ns__record(soap, &pers1))
5186 ... // handle IO error
5187 soap->is = NULL;
5188
5189 soap->os = &ss;
5190 if (soap_write__ns__record(soap, &pers1))
5191 ... // handle IO error
5192 soap->os = NULL;
5193 std::string s = ss.str(); // string with XML
5194 ~~~
5195
5196 For C we can use `soap::is` and `soap::os` to point to strings of XML content
5197 as follows (this requires gSOAP 2.8.28 or later):
5198
5199 ~~~{.cpp}
5200 soap->is = "..."; // XML to parse
5201 if (soap_read__ns__record(soap, &pers1))
5202 ... // handle IO error
5203 soap->is = NULL;
5204
5205 const char *cs = NULL;
5206 soap->os = &cs;
5207 if (soap_write__ns__record(soap, &pers1))
5208 ... // handle IO error
5209 soap->os = NULL;
5210 ... = cs; // string with XML (do not free(cs): managed by the context and freed with soap_end())
5211 ~~~
5212
5213 The type of `soap::os` is a pointer to a `const char*` string. The pointer is
5214 set by the managing `soap` context to point to the XML data that is stored on
5215 the context-managed heap.
5216
5217 For earlier gSOAP versions we recommend to use IO callbacks `soap::frecv` and
5218 `soap::fsend`, see the [gSOAP user guide.](../../guide/html/index.html).
5219
5220 🔝 [Back to table of contents](#)
5221
5222 Memory management {#memory}
5223 =================
5224
5225 Memory management with the `soap` context enables us to allocate data in
5226 context-managed heap space that can be collectively deleted. All deserialized
5227 data is placed on the context-managed heap by the `soap` context of the engine.
5228
5229 🔝 [Back to table of contents](#)
5230
5231 Memory management in C {#memory1}
5232 ----------------------
5233
5234 When working with gSOAP in C (i.e. using <b>`wsdl2h -c`</b> option <b>`-c`</b>
5235 or <b>`soapcpp2 -c`</b> option <b>`-c`</b>), data is allocated on the managed heap with:
5236
5237 - `void *soap_malloc(struct soap*, size_t len)`.
5238
5239 This function allocates `len` bytes on the heap managed by the specified
5240 context and returns NULL when allocation failed.
5241
5242 You can also make shallow copies of data with `soap_memdup` that uses
5243 `soap_malloc` and a safe version of `memcpy` to copy a chunk of data `src` with
5244 length `len` to the context-managed heap:
5245
5246 - `void * soap_memdup(struct soap*, const void *src, size_t len)`
5247
5248 This function returns a pointer to the copy. This function requires gSOAP
5249 2.8.27 or later.
5250
5251 In gSOAP 2.8.35 and greater versions, you can use an auto-generated function to
5252 allocate and initialize data of type `T` on the managed heap:
5253
5254 - `T * soap_new_T(struct soap*, int n)`
5255
5256 This function returns an array of length `n` of type `T` data that is default
5257 initialized (by internally calling `soap_malloc(soap, n * sizeof(T))` and then
5258 `soap_default_T(soap, T*)` on each array value). Use a negative value or `n=1`
5259 to allocate and initialize a single value. This function returns NULL when
5260 allocation failed.
5261
5262 The `soap_malloc` function is essentially a wrapper around `malloc`, but
5263 permits the `soap` context to track all heap allocations for collective
5264 deletion with `soap_end(soap)`:
5265
5266 ~~~{.cpp}
5267 #include "soapH.h"
5268 #include "ns.nsmap"
5269 ...
5270 struct soap *soap = soap_new(); // new context
5271 ...
5272 struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
5273 soap_default_ns__record(soap, record); // auto-generated struct initializer
5274 ...
5275 soap_destroy(soap); // only for C++, see section on C++ below
5276 soap_end(soap); // delete record and all other heap allocations
5277 soap_free(soap); // delete context
5278 ~~~
5279
5280 All data on the managed heap is mass-deleted with `soap_end(soap)` which must
5281 be called before `soap_done(soap)` or `soap_free(soap)`, which end the use of
5282 the `soap` context and free the context, respectively. Use
5283 `soap_free(soap)` only when the context is allocated with `soap_new()`. Use
5284 `soap_done(soap)` only when the context is stack allocated (so cannot be
5285 deleted from the heap).
5286
5287 The managed heap is checked for memory leaks at run time when the source code
5288 is compiled with option <b>`-DDEBUG`</b>.
5289
5290 The soapcpp2 auto-generated deserializers in C use `soap_malloc` to allocate
5291 and populate deserialized structures, which are managed by the context for
5292 collective deletion.
5293
5294 To make `char*` and `wchar_t*` string copies to the context-managed heap, we
5295 can use the functions:
5296
5297 - `char *soap_strdup(struct soap*, const char *str)` and
5298
5299 - `wchar_t *soap_wstrdup(struct soap*, const wchar_t *wstr)`.
5300
5301 If your C compiler supports `typeof` then you can use the following macro to
5302 simplify the managed heap allocation and initialization of primitive values:
5303
5304 ~~~{.cpp}
5305 #define soap_assign(soap, lhs, rhs) (*(lhs = (typeof(lhs))soap_malloc(soap, sizeof(*lhs))) = rhs)
5306 ~~~
5307
5308 Pointers to primitive values are often used for optional members. For example,
5309 assume we have the following struct:
5310
5311 ~~~{.cpp}
5312 struct ns__record
5313 {
5314 const char *name 1; // required (minOccurs=1)
5315 uint64_t *SSN; // optional (pointer means minOccurs=0)
5316 struct ns__record *spouse; // optional (pointer means minOccurs=0)
5317 };
5318 ~~~
5319
5320 Use `soap_assign` to create a SSN value on the managed heap:
5321
5322 ~~~{.cpp}
5323 struct soap *soap = soap_new(); // new context
5324 ...
5325 struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
5326 soap_default_ns__record(soap, record);
5327 record->name = soap_strdup(soap, "Joe");
5328 soap_assign(soap, record->SSN, 1234567890UL);
5329 ...
5330 soap_end(soap); // delete managed soap_malloc'ed heap data
5331 soap_free(soap); // delete context
5332 ~~~
5333
5334 Without the `soap_assign` macro, you will need two lines of code, one to
5335 allocate and one to assign (you should also use this if your system can run out
5336 of memory):
5337
5338 ~~~{.cpp}
5339 assert((record->SSN = (uint64_t*)soap_malloc(soap, sizeof(utint64_t))) != NULL);
5340 *record->SSN = 1234567890UL;
5341 ~~~
5342
5343 The serializer can serialize any heap, stack, or static allocated data. So we
5344 can also create a new record as follows:
5345
5346 ~~~{.cpp}
5347 struct soap *soap = soap_new(); // new context
5348 ...
5349 struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
5350 static uint64_t SSN = 1234567890UL;
5351 soap_default_ns__record(soap, record);
5352 record->name = "Joe";
5353 record->SSN = &SSN; // safe to use static values: the value of record->SSN is never changed
5354 ...
5355 soap_end(soap); // delete managed soap_malloc'ed heap data
5356 soap_free(soap); // delete context
5357 ~~~
5358
5359 Use the soapcpp2 auto-generated `soap_dup_T` functions to duplicate data into
5360 another `soap` context (this requires <b>`soapcpp2 -Ec`</b> option <b>`-Ec`</b> to
5361 generate), here shown for C with the second argument `dst` NULL because we want
5362 to allocate a new managed structure:
5363
5364 ~~~{.cpp}
5365 struct soap *other_soap = soap_new(); // another context
5366 struct ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
5367 ...
5368 soap_destroy(other_soap); // only for C++, see section on C++ below
5369 soap_end(other_soap); // delete other_record and all of its deep data
5370 soap_free(other_soap); // delete context
5371 ~~~
5372
5373 The only reason to use another `soap` context and not to use the primary `soap`
5374 context is when the primary context must be destroyed together with all of the
5375 objects it manages while some of the objects must be kept alive. If the
5376 objects that are kept alive contain deep cycles then this is the only option we
5377 have, because deep copy with a managing `soap` context detects and preserves
5378 these cycles unless the `SOAP_XML_TREE` flag is used with the `soap` context:
5379
5380 ~~~{.cpp}
5381 struct soap *other_soap = soap_new1(SOAP_XML_TREE); // another context
5382 struct ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
5383 ~~~
5384
5385 The resulting deep copy will be a full copy of the source data structure as a
5386 tree without co-referenced data (i.e. no digraph) and without cycles. Cycles
5387 are pruned and (one of the) pointers that forms a cycle is repaced by NULL.
5388
5389 You can also deep copy into unmanaged space and use the auto-generated
5390 `soap_del_T()` function (requires <b>`soapcpp2 -Ed`</b> option <b>`-Ed`</b> to generate) to delete
5391 it later:
5392
5393 ~~~{.cpp}
5394 struct ns__record *other_record = soap_dup_ns__record(NULL, NULL, record);
5395 ...
5396 soap_del_ns__record(other_record); // deep delete record data members
5397 free(other_record); // delete the record
5398 ~~~
5399
5400 But you should not do this for any data that has deep cycles in its runtime
5401 data structure. Cycles in the data structure will lead to non-termination when
5402 making unmanaged deep copies. Consider for example:
5403
5404 ~~~{.cpp}
5405 struct ns__record
5406 {
5407 const char *name 1; // required (minOccurs=1)
5408 uint64_t SSN; // required (non-pointer means minOccurs=1)
5409 struct ns__record *spouse; // optional (pointer means minOccurs=0)
5410 };
5411 ~~~
5412
5413 The code to populate a structure with a mutual spouse relationship:
5414
5415 ~~~{.cpp}
5416 struct soap *soap = soap_new();
5417 ...
5418 struct ns__record pers1, pers2;
5419 soap_default_ns__record(soap, &pers1);
5420 soap_default_ns__record(soap, &pers2);
5421 pers1.name = "Joe"; // OK to serialize static data
5422 pers1.SSN = 1234567890;
5423 pers1.spouse = &pers2;
5424 pers2.name = soap_strdup(soap, "Jane"); // allocates and copies a string
5425 pers2.SSN = 1987654320;
5426 pers2.spouse = &pers1;
5427 ...
5428 struct ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5429 struct ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5430 soap_set_mode(soap, SOAP_XML_TREE);
5431 struct ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5432 ~~~
5433
5434 The bad case is where there is no context used in the first argument. The deep
5435 copy functions use a context to keep track of co-referenced data nodes and
5436 cycles in the data structure copies, to copy co-referenced nodes just once.
5437 Co-references in a data structure are formed by pointers and smart pointers
5438 such as `std::shared_ptr`, such that at least two pointers point to the same
5439 data.
5440
5441 The serializer can serialize any heap, stack, or static allocated data, such as
5442 in the code shown above. So we can serialize the stack-allocated `pers1`
5443 record as follows:
5444
5445 ~~~{.cpp}
5446 FILE *fp = fopen("record.xml", "w");
5447 if (fp != NULL)
5448 {
5449 soap->sendfd = fileno(fp); // file descriptor to write to
5450 soap_set_mode(soap, SOAP_XML_GRAPH); // support id-ref w/o requiring SOAP
5451 soap_clr_mode(soap, SOAP_XML_TREE); // if set, clear
5452 soap_write_ns__record(soap, &pers1);
5453 fclose(fp);
5454 soap->sendfd = -1; // block further writing
5455 }
5456 ~~~
5457
5458 which produces an XML document record.xml that is similar to:
5459
5460 <div class="alt">
5461 ~~~{.xml}
5462 <ns:record xmlns:ns="urn:types" id="Joe">
5463 <name>Joe</name>
5464 <SSN>1234567890</SSN>
5465 <spouse id="Jane">
5466 <name>Jane</name>
5467 <SSN>1987654320</SSN>
5468 <spouse ref="#Joe"/>
5469 </spouse>
5470 </ns:record>
5471 ~~~
5472 </div>
5473
5474 Deserialization of an XML document with a SOAP 1.1/1.2 encoded id-ref graph
5475 leads to the same non-termination problem when we later try to copy the data
5476 into unmanaged memory heap space:
5477
5478 ~~~{.cpp}
5479 struct soap *soap = soap_new1(SOAP_XML_GRAPH); // support id-ref w/o SOAP
5480 ...
5481 struct ns__record pers1;
5482 FILE *fp = fopen("record.xml", "r");
5483 if (fp != NULL)
5484 {
5485 soap->recvfd = fileno(fp);
5486 if (soap_read_ns__record(soap, &pers1))
5487 ... // handle IO error
5488 fclose(fp);
5489 soap->recvfd = -1; // blocks further reading
5490 }
5491 ...
5492 struct ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5493 struct ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5494 soap_set_mode(soap, SOAP_XML_TREE);
5495 struct ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5496 ~~~
5497
5498 Copying data with `soap_dup_T(soap)` into managed heap memory space is always
5499 safe. Copying into unmanaged heap memory space requires diligence. But
5500 deleting unmanaged data is easy with `soap_del_T()`.
5501
5502 You can also use `soap_del_T()` to delete structures that you created in C, but
5503 only if these structures are created with `malloc` and do NOT contain pointers
5504 to stack and static data.
5505
5506 You can unlink one or more allocated objects from the managed heap to allow the
5507 object to live after `soap_end(soap)` by using:
5508
5509 - `void soap_unlink(struct soap *soap, void *ptr)`
5510
5511 The unlinked heap-allocated data pointed to by `ptr` can be accessed after
5512 `soap_end(soap)`. Do not forget to free the data with `free(ptr)`. Be aware
5513 that `soap_unlink(soap, ptr)` does not perform a deep unlinkage. If `ptr` is a
5514 struct, pointer members will become invalid when pointing to objects on the
5515 managed heap. Use `soap_unlink(soap, ptr->member)` to unlink `member` as well.
5516
5517 Finally, when data is allocated in managed memory heap space, either explicitly
5518 with the allocation functions shown above or by the soapcpp2-generated
5519 deserializers, you can delegate the management and deletion of this data to
5520 another `soap` context. That context will be responsible to delete the data
5521 with `soap_end(soap)` later:
5522
5523 - `void delegate_deletion(struct soap *soap_from, struct soap *soap_to)`
5524
5525 This allows the `soap_from` context to be deleted with `soap_free(soap_from)`
5526 (assuming it is allocated with `soap_new()`, use `soap_done(soap_from)` when
5527 `soap_from` is stack-allocated) while the managed data remains intact. You
5528 can use this function any time, to delegate management and deletion to another
5529 context `soap_to` and then continue with the current context. You can also use
5530 different source `soap_from` contexts to delegate management and deletion to
5531 the other `soap_to` context. To mass delete all managed data, use
5532 `soap_end(soap_to)`.
5533
5534 🔝 [Back to table of contents](#)
5535
5536 Memory management in C++ {#memory2}
5537 ------------------------
5538
5539 When working with gSOAP in C++, the engine allocates data on a managed heap
5540 using `soap_new_T(soap)` to allocate a type with type name `T`. Managed heap
5541 allocation is tracked by the `soap` context for collective deletion with
5542 `soap_destroy(soap)` for structs, classes, and templates and with
5543 `soap_end(soap)` for everything else.
5544
5545 You should only use `soap_malloc(struct soap*, size_t len)` to allocate
5546 primitive types because constructors are not invoked. Therefore, `soap_new_T`
5547 is preferred. The auto-generated `T * soap_new_T(struct soap*)` returns data
5548 allocated on the managed heap for type `T`. The data is mass-deleted with
5549 `soap_destroy(soap)` followed by `soap_end(soap)`.
5550
5551 The `soap_new_T` functions return NULL when allocation fails. C++ exceptions
5552 are never raised by the engine and serializers when data is allocated.
5553
5554 There are four variations of `soap_new_T` functions to allocate data of type
5555 `T` that soapcpp2 auto-generates:
5556
5557 - `T * soap_new_T(struct soap*)` returns a new instance of `T` that is default
5558 initialized. For classes, initialization is internally performed using the
5559 soapcpp2 auto-generated `void T::soap_default(struct soap*)` method of the
5560 class, but ONLY IF the soapcpp2 auto-generated default constructor is used
5561 that invokes `soap_default()` and was not replaced by a user-defined default
5562 constructor.
5563
5564 - `T * soap_new_T(struct soap*, int n)` returns an array of `n` new instances of
5565 `T`. The instances in the array are default initialized as described above.
5566
5567 - `T * soap_new_req_T(struct soap*, ...)` (structs and classes only) returns a
5568 new instance of `T` and sets the required data members to the values
5569 specified in `...`. The required data members are those with nonzero
5570 minOccurs, see the subsections on
5571 [(smart) pointer members and their occurrence constraints](#toxsd9-8) and
5572 [container and array members and their occurrence constraints](#toxsd9-9).
5573
5574 - `T * soap_new_set_T(struct soap*, ...)` (structs and classes only) returns a
5575 new instance of `T` and sets the public/serializable data members to the values
5576 specified in `...`.
5577
5578 The above functions can be invoked with a NULL `soap` context, but you are then
5579 responsible to use `delete T` to remove this instance from the unmanaged heap.
5580
5581 For example, to allocate a managed `std::string` you can use:
5582
5583 ~~~{.cpp}
5584 std::string *s = soap_new_std__string(soap);
5585 ~~~
5586
5587 To throw a `std::bad_alloc` exception when memory allocation fails, we can define the
5588 following class and macro:
5589
5590 ~~~{.cpp}
5591 class alloc_check {
5592 public:
5593 template<typename T>
5594 T operator=(T ptr)
5595 {
5596 if (ptr == NULL)
5597 throw std::bad_alloc();
5598 return ptr;
5599 }
5600 };
5601
5602 #define CHECK alloc_check() =
5603 ~~~
5604
5605 And use `CHECK` as follows to throw an exception when memory allocation fails:
5606
5607 ~~~{.cpp}
5608 std::string *s = CHECK soap_new_std__string(soap);
5609 ~~~
5610
5611 To throw a `std::runtime_exception` when memory allocation fails, with file
5612 and line number information where the error occurred, we can define the
5613 following revised version of our exception-throwing macro:
5614
5615 ~~~{.cpp}
5616 class alloc_failure : public std::runtime_error {
5617 public:
5618 alloc_failure(const char *file, size_t line) : std::runtime_error(error(file, line))
5619 { }
5620 private:
5621 std::string error(const char *file, size_t line) const
5622 {
5623 std::stringstream ss;
5624 ss << "Memory allocation failed in " << file << " at line " << line;
5625 return ss.str();
5626 }
5627 };
5628
5629 class alloc_check_with_info {
5630 public:
5631 alloc_check_with_info(const char *file, size_t line) : file(file), line(line)
5632 { }
5633 template<typename T>
5634 T operator=(T ptr) const
5635 {
5636 if (ptr == NULL)
5637 throw alloc_failure(file, line);
5638 return ptr;
5639 }
5640 const char *file;
5641 size_t line;
5642 };
5643
5644 #define CHECK alloc_check_with_info(__FILE__, __LINE__) =
5645 ~~~
5646
5647 And use `CHECK` as follows to throw an exception with the file and line number
5648 of the location where memory allocation failed:
5649
5650 ~~~{.cpp}
5651 std::string *s = CHECK soap_new_std__string(soap);
5652 ~~~
5653
5654 Primitive types and arrays of primitive values may be allocated with
5655 `soap_malloc` (actually, `soap_new_T` calls `soap_malloc` for primitive type
5656 `T`). All primitive types (i.e. no classes, structs, class templates,
5657 containers, and smart pointers) are allocated with `soap_malloc` for reasons of
5658 efficiency.
5659
5660 You can use a C++ template to simplify the managed allocation and initialization
5661 of primitive values as follows (this is for primitive types only):
5662
5663 ~~~{.cpp}
5664 template<class T>
5665 T * soap_make(struct soap *soap, T val)
5666 {
5667 T *p = (T*)soap_malloc(soap, sizeof(T));
5668 if (p == NULL)
5669 throw std::bad_alloc();
5670 *p = val;
5671 return p;
5672 }
5673 ~~~
5674
5675 For example, assuming we have the following class:
5676
5677 ~~~{.cpp}
5678 class ns__record
5679 {
5680 public:
5681 std::string name; // required (non-pointer means minOccurs=1)
5682 uint64_t *SSN; // optional (pointer means minOccurs=0)
5683 ns__record *spouse; // optional (pointer means minOccurs=0)
5684 };
5685 ~~~
5686
5687 You can instantiate a record by using the auto-generated
5688 `soap_new_set_ns__record` and use `soap_make` to create a SSN value on the
5689 managed heap as follows:
5690
5691 ~~~{.cpp}
5692 soap *soap = soap_new(); // new context
5693 ...
5694 ns__record *record = soap_new_set_ns__record(
5695 soap,
5696 "Joe",
5697 soap_make<uint64_t>(soap, 1234567890UL),
5698 NULL);
5699 ...
5700 soap_destroy(soap); // delete record and all other managed instances
5701 soap_end(soap); // delete managed soap_malloc'ed heap data
5702 soap_free(soap); // delete context
5703 ~~~
5704
5705 All data on the managed heap is mass-deleted with `soap_end(soap)` which must
5706 be called before `soap_done(soap)` or `soap_free(soap)`, which end the use of
5707 the `soap` context and free the context, respectively. Use
5708 `soap_free(soap)` only when the context is allocated with `soap_new()`. Use
5709 `soap_done(soap)` only when the context is stack allocated (so cannot be
5710 deleted from the heap).
5711
5712 The managed heap is checked for memory leaks at run time when the source code
5713 is compiled with option <b>`-DDEBUG`</b>.
5714
5715 However, the serializer can serialize any heap, stack, or static allocated
5716 data. So we can also create a new record as follows:
5717
5718 ~~~{.cpp}
5719 uint64_t SSN = 1234567890UL;
5720 ns__record *record = soap_new_set_ns__record(soap, "Joe", &SSN, NULL);
5721 ~~~
5722
5723 which will be fine to serialize this record as long as the local `SSN`
5724 stack-allocated value remains in scope when invoking the serializer and/or
5725 using `record`. It does not matter if `soap_destroy` and `soap_end` are called
5726 beyond the scope of `SSN`.
5727
5728 To facilitate class methods to access the managing context, we can add a soap
5729 context pointer to a class/struct:
5730
5731 ~~~{.cpp}
5732 class ns__record
5733 {
5734 public:
5735 ...
5736 void create_more(); // needs a context to create more internal data
5737 protected:
5738 struct soap *soap; // the context that manages this instance, or NULL
5739 };
5740 ~~~
5741
5742 The `soap` context pointer member of the class is set when invoking
5743 `soap_new_T` (and similar) with a non-NULL context argument that will be
5744 assigned to the `soap` member of the class.
5745
5746 You can also use a template when an array of pointers to values is required.
5747 To create an array of pointers to values, define the following template:
5748
5749 ~~~{.cpp}
5750 template<class T>
5751 T **soap_make_array(struct soap *soap, T* array, int n) throw (std::bad_alloc)
5752 {
5753 T **p = (T**)soap_malloc(soap, n * sizeof(T*));
5754 if (p == NULL)
5755 throw std::bad_alloc();
5756 for (int i = 0; i < n; ++i)
5757 p[i] = &array[i];
5758 return p;
5759 }
5760 ~~~
5761
5762 The `array` parameter is a pointer to an array of `n` values. The template
5763 returns an array of `n` pointers that point to the values in that array:
5764
5765 ~~~{.cpp}
5766 // create an array of 100 pointers to 100 records
5767 int n = 100;
5768 ns__record **precords = soap_make_array(soap, soap_new_ns__record(soap, n), n);
5769 for (int i = 0; i < n; ++i)
5770 {
5771 precords[i]->name = "...";
5772 precords[i]->SSN = soap_make<uint64_t>(1234567890UL + i);
5773 }
5774 ~~~
5775
5776 Note that `soap_new_ns__record(soap, n)` returns a pointer to an array of `n`
5777 records, which is then used to create an array of `n` pointers to these records.
5778
5779 Use the soapcpp2 auto-generated `soap_dup_T` functions to duplicate data into
5780 another `soap` context (this requires <b>`soapcpp2 -Ec`</b> option <b>`-Ec`</b> to generate), here shown
5781 for C++ with the second argument `dst` NULL to allocate a new managed object:
5782
5783 ~~~{.cpp}
5784 soap *other_soap = soap_new(); // another context
5785 ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
5786 ...
5787 soap_destroy(other_soap); // delete record and other managed instances
5788 soap_end(other_soap); // delete other data (the SSNs on the heap)
5789 soap_free(other_soap); // delete context
5790 ~~~
5791
5792 To duplicate base and derived instances when a base class pointer or reference
5793 is provided, use the auto-generated method `T * T::soap_dup(struct soap*)`:
5794
5795 ~~~{.cpp}
5796 soap *other_soap = soap_new(); // another context
5797 ns__record *other_record = record->soap_dup(other_soap);
5798 ...
5799 soap_destroy(other_soap); // delete record and other managed instances
5800 soap_end(other_soap); // delete other data (the SSNs on the heap)
5801 soap_free(other_soap); // delete context
5802 ~~~
5803
5804 The only reason to use another context and not to use the primary `soap`
5805 context is when the primary context must be destroyed together with all of the
5806 objects it manages while some of the objects must be kept alive. If the
5807 objects that are kept alive contain deep cycles then this is the only option we
5808 have, because deep copy with a managing `soap` context detects and preserves
5809 these cycles unless the `SOAP_XML_TREE` flag is used with the context:
5810
5811 ~~~{.cpp}
5812 soap *other_soap = soap_new1(SOAP_XML_TREE); // another context
5813 ns__record *other_record = record->soap_dup(other_soap); // deep tree copy
5814 ~~~
5815
5816 The resulting deep copy will be a full copy of the source data structure as a
5817 tree without co-referenced data (i.e. no digraph) and without cycles. Cycles
5818 are pruned and (one of the) pointers that forms a cycle is repaced by NULL.
5819
5820 You can also deep copy into unmanaged space and use the auto-generated
5821 `soap_del_T()` function or the `T::soap_del()` method (requires
5822 <b>`soapcpp2 -Ec`</b> option <b>`-Ec`</b> to generate) to delete it later,
5823 but we should not do this for any data that has deep cycles in its runtime data
5824 structure graph:
5825
5826 ~~~{.cpp}
5827 ns__record *other_record = record->soap_dup(NULL);
5828 ...
5829 other_record->soap_del(); // deep delete record data members
5830 delete other_record; // delete the record
5831 ~~~
5832
5833 Cycles in the data structure will lead to non-termination when making unmanaged
5834 deep copies. Consider for example:
5835
5836 ~~~{.cpp}
5837 class ns__record
5838 {
5839 public:
5840 const char *name 1; // required (minOccurs=1)
5841 uint64_t SSN; // required (non-pointer means minOccurs=1)
5842 ns__record *spouse; // optional (pointer means minOccurs=1)
5843 };
5844 ~~~
5845
5846 The code to populate a structure with a mutual spouse relationship:
5847
5848 ~~~{.cpp}
5849 soap *soap = soap_new();
5850 ...
5851 ns__record pers1, pers2;
5852 pers1.name = "Joe";
5853 pers1.SSN = 1234567890;
5854 pers1.spouse = &pers2;
5855 pers2.name = "Jane";
5856 pers2.SSN = 1987654320;
5857 pers2.spouse = &pers1;
5858 ...
5859 ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5860 ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5861 soap_set_mode(soap, SOAP_XML_TREE);
5862 ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5863 ~~~
5864
5865 The serializer can serialize any heap, stack, or static allocated data, such as
5866 shown in the code shown above. So we can serialize the stack-allocated `pers1`
5867 record as follows:
5868
5869 ~~~{.cpp}
5870 FILE *fp = fopen("record.xml", "w");
5871 if (fp != NULL)
5872 {
5873 soap->sendfd = fileno(fp); // file descriptor to write to
5874 soap_set_mode(soap, SOAP_XML_GRAPH); // support id-ref w/o requiring SOAP
5875 soap_clr_mode(soap, SOAP_XML_TREE); // if set, clear
5876 if (soap_write_ns__record(soap, &pers1))
5877 ... // handle IO error
5878 fclose(fp);
5879 soap->sendfd = -1; // block further writing
5880 }
5881 ~~~
5882
5883 which produces an XML document record.xml that is similar to:
5884
5885 <div class="alt">
5886 ~~~{.xml}
5887 <ns:record xmlns:ns="urn:types" id="Joe">
5888 <name>Joe</name>
5889 <SSN>1234567890</SSN>
5890 <spouse id="Jane">
5891 <name>Jane</name>
5892 <SSN>1987654320</SSN>
5893 <spouse ref="#Joe"/>
5894 </spouse>
5895 </ns:record>
5896 ~~~
5897 </div>
5898
5899 Deserialization of an XML document with a SOAP 1.1/1.2 encoded id-ref graph
5900 leads to the same non-termination problem when we later try to copy the data
5901 into unmanaged space:
5902
5903 ~~~{.cpp}
5904 soap *soap = soap_new1(SOAP_XML_GRAPH); // support id-ref w/o SOAP
5905 ...
5906 ns__record pers1;
5907 FILE *fp = fopen("record.xml", "r");
5908 if (fp != NULL)
5909 {
5910 soap->recvfd = fileno(fp); // file descriptor to read from
5911 if (soap_read_ns__record(soap, &pers1))
5912 ... // handle IO error
5913 fclose(fp);
5914 soap->recvfd = -1; // block further reading
5915 }
5916 ...
5917 ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5918 ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5919 soap_set_mode(soap, SOAP_XML_TREE);
5920 ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5921 ~~~
5922
5923 Copying data with `soap_dup_T(soap)` into managed space is always safe. Copying
5924 into unmanaged space requires diligence. But deleting unmanaged data is easy
5925 with `soap_del_T()`.
5926
5927 You can also use `soap_del_T()` to delete structures in C++, but only if these
5928 structures are created with `new` (and `new []` for arrays when applicable) for
5929 classes, structs, and class templates and with `malloc` for anything else, and
5930 the structures do NOT contain pointers to stack and static data.
5931
5932 You can unlink one or more allocated objects from the managed heap to allow the
5933 object to live after `soap_destroy(soap)` and `soap_end(soap)` by using:
5934
5935 - `void soap_unlink(struct soap *soap, void *ptr)`
5936
5937 The unlinked heap-allocated data pointed to by `ptr` can be accessed after
5938 `soap_destroy(soap)` and `soap_end(soap)`. Do not forget to free the data with
5939 `delete ptr` (C++ class instance only) or with `free(ptr)` (non-class data).
5940 Be aware that `soap_unlink(soap, ptr)` does not perform a deep unlinkage. If
5941 `ptr` is a struct or class, pointer members will become invalid when pointing
5942 to objects on the managed heap. Use `soap_unlink(soap, ptr->member)` to unlink
5943 `member` as well.
5944
5945 Finally, when data is allocated in managed memory heap space, either explicitly
5946 with the allocation functions shown above or by the soapcpp2-generated
5947 deserializers, you can delegate the management and deletion of this data to
5948 another `soap` context. That context will be responsible to delete the data
5949 with `soap_destroy(soap)` and `soap_end(soap)` later:
5950
5951 - `void delegate_deletion(struct soap *soap_from, struct soap *soap_to)`
5952
5953 This allows the `soap_from` context to be deleted with `soap_free(soap_from)`
5954 (assuming it is allocated with `soap_new()`, use `soap_done(soap_from)` when
5955 `soap_from` is stack-allocated) while the managed data remains intact. You
5956 can use this function any time, to delegate management and deletion to another
5957 context `soap_to` and then continue with the current context. You can also use
5958 different source `soap_from` contexts to delegate management and deletion to
5959 the other `soap_to` context. To mass delete all managed data, use
5960 `soap_destroy(soap_to)` followed by `soap_end(soap_to)`.
5961
5962 🔝 [Back to table of contents](#)
5963
5964 Context flags to initialize the soap struct {#flags}
5965 ===========================================
5966
5967 There are several `soap` context initialization flags and context mode flags to
5968 control XML serialization at runtime. The flags are set with `soap_new1()` to
5969 allocate and initialize a new context:
5970
5971 ~~~{.cpp}
5972 struct soap *soap = soap_new1(flag1 | flag2 | ... | flagn);
5973 ...
5974 soap_destroy(soap); // delete objects
5975 soap_end(soap); // delete other data and temp data
5976 soap_free(soap); // free context
5977 ~~~
5978
5979 and with `soap_init1()` for stack-allocated contexts:
5980
5981 ~~~{.cpp}
5982 struct soap soap;
5983 soap_init1(&soap, flag1 | flag2 | ... | flagn);
5984 ...
5985 soap_destroy(&soap); // delete objects
5986 soap_end(&soap); // delete other data and temp data
5987 soap_done(&soap); // clear context
5988 ~~~
5989
5990 where `flag1`, `flag2`, ..., `flagn` is one of:
5991
5992 - `SOAP_C_UTFSTRING`: enables all `std::string` and `char*` strings to
5993 contain UTF-8 content. This option is recommended.
5994
5995 - `SOAP_C_NILSTRING`: treat empty strings as if they were NULL pointers, i.e.
5996 omits elements and attributes when empty.
5997
5998 - `SOAP_XML_STRICT`: strictly validates XML while deserializing. Should not be
5999 used together with SOAP 1.1/1.2 encoding style of messaging. Use
6000 <b>`soapcpp2 -s`</b> option <b>`-s`</b> to hard code `SOAP_XML_STRICT` in the
6001 generated serializers. Not recommended with SOAP 1.1/1.2 encoding style
6002 messaging.
6003
6004 - `SOAP_XML_INDENT`: produces indented XML.
6005
6006 - `SOAP_XML_CANONICAL`: c14n canonocalization, removes unused `xmlns` bindings
6007 and adds them to appropriate places by applying c14n normalization rules.
6008 Should not be used together with SOAP 1.1/1.2 encoding style messaging.
6009
6010 - `SOAP_XML_TREE`: write tree XML without id-ref, while pruning data structure
6011 cycles to prevent nontermination of the serializer for cyclic structures.
6012
6013 - `SOAP_XML_GRAPH`: write graph (digraph and cyclic graphs with shared pointers
6014 to objects) using id-ref attributes. That is, XML with SOAP multi-ref
6015 encoded id-ref elements. This is a structure-preserving serialization format,
6016 because co-referenced data and also cyclic relations are accurately represented.
6017
6018 - `SOAP_XML_DEFAULTNS`: uses xmlns default namespace declarations, assuming
6019 that the schema attribute form is "qualified" by default (be warned if it is
6020 not, since attributes in the null namespace will get bound to namespaces!).
6021
6022 - `SOAP_XML_NIL`: emit empty element with <i>`xsi:nil`</i> for all NULL pointers
6023 serialized.
6024
6025 - `SOAP_XML_IGNORENS`: the XML parser ignores XML namespaces, i.e. element and
6026 attribute tag names match independent of their namespace.
6027
6028 - `SOAP_XML_NOTYPE`: removes all <i>`xsi:type`</i> attribuation. This option is usually
6029 not needed unless the receiver rejects all <i>`xsi:type`</i> attributes. This option
6030 may affect the quality of the deserializer, which relies on <i>`xsi:type`</i>
6031 attributes to distinguish base class instances from derived class instances
6032 transported in the XML payloads.
6033
6034 - `SOAP_IO_CHUNK`: to enable HTTP chunked transfers.
6035
6036 - `SOAP_IO_STORE`: full buffering of outbound messages.
6037
6038 - `SOAP_ENC_ZLIB`: compress messages, requires compiling with option <b>`-DWITH_GZIP`</b> and
6039 linking with zlib using option <b>`-lz`</b>.
6040
6041 - `SOAP_ENC_MIME`: enable MIME attachments, see
6042 [DIME/MIME/MTOM attachment binary types](#toxsd10-3).
6043
6044 - `SOAP_ENC_MTOM`: enable MTOM attachments, see
6045 [DIME/MIME/MTOM attachment binary types](#toxsd10-3).
6046
6047 @note C++ Web service proxy and service classes have their own `soap` context, either
6048 as a base class (with <b>`soapcpp2 -i`</b> option <b>`-i`</b>) or as a pointer member `soap` that points to
6049 a context (with <b>`soapcpp2 -j`</b> option <b>`-j`</b>). These contexts are allocated when the proxy or
6050 service is instantiated with context flags that are passed to the constructor.
6051
6052 🔝 [Back to table of contents](#)
6053
6054 Context parameter settings {#params}
6055 ==========================
6056
6057 After allocation and initializtion of a `soap` context, several context
6058 parameters can be set (some parameters may require 2.8.31 or greater):
6059
6060 - `unsigned int soap::maxlevel` is the maximum XML nesting depth levels that
6061 the parser permits. Default initialized to `SOAP_MAXLEVEL` (10000), which is
6062 a redefinable macro in <i>`gsoap/stdsoap2.h`</i>. Set `soap::maxlevel` to a
6063 lower value to restrict XML parsing nesting depth.
6064
6065 - `long soap::maxlength` is the maximum string content length if not already
6066 constrained by an XML schema validation `maxLength` constraint. Zero means
6067 unlimited string lengths are permitted (unless restricted by XML schema
6068 `maxLength`). Default initialized to `SOAP_MAXLENGTH` (0), which is a
6069 redefinable macro in <i>`gsoap/stdsoap2.h`</i>. Set `soap::maxlength` to a
6070 positive value to restrict the number of (wide) characters in strings parsed,
6071 restrict hexBinary byte length, and restrict base64Binary byte length.
6072
6073 - `size_t soap::maxoccurs` is the maximum number of array or container elements
6074 permitted by the parser. Must be greater than zero (0). Default initialized
6075 to `SOAP_MAXOCCURS` (100000), which is a redefinable macro in
6076 <i>`gsoap/stdsoap2.h`</i>. Set `soap::maxoccurs` to a positive value to
6077 restrict the number of array and container elements that can be parsed.
6078
6079 - `soap::version` is the SOAP version used, with 0 for non-SOAP, 1 for SOAP1.1,
6080 and 2 for SOAP1.2. This value is normally set by web service operations, and
6081 is otherwise 0 (non-SOAP). Use `soap_set_version(struct soap*, short)` to
6082 set the value. This controls XML namespaces and SOAP id-ref serialization
6083 when applicable with an encodingStyle (see below).
6084
6085 - `const char *soap::encodingStyle` is a string that is used with SOAP
6086 encoding, normally NULL for non-SOAP XML. Set this string to "" (empty
6087 string) to enable SOAP encoding style, which supports id-ref graph
6088 serialization (see also the `SOAP_XML_GRAPH` [context flag](#flags)).
6089
6090 - `int soap::recvfd` is the file descriptor to read and parse source data from.
6091 Default initialized to 0 (stdin). See also [input and output](#io).
6092
6093 - `int soap::sendfd` is the file descriptor to write data to. Default
6094 initialized to 1 (stdout). See also [input and output](#io).
6095
6096 - `const char *is` for C: string to read and parse source data from, overriding
6097 the `recvfd` source. Normally NULL. This value must be reset to NULL or
6098 the parser will continue to read from this string content until the NUL
6099 character. See also [input and output](#io).
6100
6101 - `std::istream *is` for C++: an input stream to read and parse source data
6102 from, overriding the `recvfd` source. Normally NULL. This value must be
6103 reset to NULL or the parser will continue to read from this stream until EOF.
6104 See also [input and output](#io).
6105
6106 - `const char **os` for C: points to a string (a `const char *`) that will be
6107 set to point to the string output. Normally NULL. This value must be reset
6108 to NULL or the next output will result in reassigning the pointer to point to
6109 the next string that is output. The strings are automatically deallocated by
6110 `soap_end(soap)`. See also [input and output](#io).
6111
6112 - `std::ostream *os` for C++: an output stream to write output to. Normally
6113 NULL. This value must be reste to NULL or the next output will be send to
6114 this stream. See also [input and output](#io).
6115
6116 🔝 [Back to table of contents](#)
6117
6118 Error handling and reporting {#errors}
6119 ============================
6120
6121 The gSOAP API functions return `SOAP_OK` (zero) or a non-zero error code. The
6122 error code is stored in `int soap::error` of the current `soap` context.
6123 Error messages can be displayed with:
6124
6125 - `void soap_stream_fault(struct soap*, std::ostream &os)` for C++ only, prints
6126 the error message to an output stream.
6127
6128 - `void soap_print_fault(struct soap*, FILE *fd)` prints the error message to a
6129 FILE descriptor.
6130
6131 - `void soap_sprint_fault(struct soap*, char *buf, size_t len)` saves the error
6132 message to a fixed-size buffer allocated with a maximum length.
6133
6134 - `void soap_print_fault_location(struct soap*, FILE *fd)` prints the location
6135 and part of the XML where the parser encountered an error.
6136
6137 C++ exceptions are never raised by the engine or serializers, even when data is
6138 allocated.
6139
6140 A `SOAP_EOM` error code is returned when memory was exhausted during
6141 processing of input and/or output of data.
6142
6143 An EOF (`SOAP_EOF` or -1) error code is returned when the parser has hit EOF
6144 but expected more input, or when socket communications timed out. In addition
6145 to the `SOAP_EOF` error, the `int soap::errnum` of the `soap` context is
6146 set to the `errno` value of the operation that failed. For timeouts, the
6147 `soap::ernum` value is always 0 instead of an `errno` error code.
6148
6149 Use `soap_xml_error_check(soap->error)` to check for XML errors. This returns
6150 true (non-zero) when a parsing and validation error has occurred.
6151
6152 For example:
6153
6154 ~~~{.cpp}
6155 #include <sstream>
6156
6157 struct soap *soap = soap_new1(SOAP_XML_INDENT | SOAP_XML_STRICT | SOAP_XML_TREE);
6158 struct ns__record person;
6159 std::stringstream ss;
6160 ss.str("..."); // XML to parse
6161 soap->is = &ss;
6162 if (soap_read__ns__record(soap, &person))
6163 {
6164 if (soap_xml_error_check(soap->error))
6165 std::cerr << "XML parsing error!" << std::endl;
6166 else
6167 soap_stream_fault(soap, std::cerr);
6168 }
6169 else
6170 {
6171 ... // all OK, use person record
6172 }
6173 soap_destroy(soap); // delete objects
6174 soap_end(soap); // delete other data and temp data
6175 soap_free(soap); // free context
6176 ~~~
6177
6178 When deploying your application on UNIX and Linux systems, UNIX signal handlers
6179 should be added to your code handle signals, in particular `SIGPIPE`:
6180
6181 ~~~{.cpp}
6182 signal(SIGPIPE, sigpipe_handler);
6183 ~~~
6184
6185 where the `sigpipe_handler` is a function:
6186
6187 ~~~{.cpp}
6188 void sigpipe_handler(int x) { }
6189 ~~~
6190
6191 Other UNIX signals may have to be handled as well.
6192
6193 The engine is designed for easy memory cleanup after being interrupted. Use
6194 `soap_destroy(soap)` and `soap_end(soap)`, after which the `soap` context can
6195 be reused.
6196
6197 🔝 [Back to table of contents](#)
6198
6199 Features and limitations {#features}
6200 ========================
6201
6202 In general, to use the generated code:
6203
6204 - Make sure to `#include "soapH.h"` in your code and also define a namespace
6205 table or `#include "ns.nsmap"` with the generated table, where `ns` is the
6206 namespace prefix for services.
6207
6208 - Use <b>`soapcpp2 -j`</b> option <b>`-j`</b> (C++ only) to generate C++ proxy and service objects.
6209 The auto-generated files include documented inferfaces. Compile with
6210 <i>`soapC.cpp`</i> and link with <b>`-lgsoap++`</b>, or alternatively compile
6211 <i>`gsoap/stdsoap2.cpp`</i>.
6212
6213 - Without <b>`soapcpp2 -j`</b> option <b>`-j`</b>: client-side uses the auto-generated
6214 <i>`soapClient.cpp`</i> and <i>`soapC.cpp`</i> (or C versions of those).
6215 Compile and link with <b>`-lgsoap++`</b> (<b>`-lgsoap`</b> for C), or
6216 alternatively compile <i>`gsoap/stdsoap2.cpp`</i> (<i>`gsoap/stdsoap2.c`</i>
6217 for C).
6218
6219 - Without <b>`soapcpp2 -j`</b> option <b>`-j`</b>: server-side uses the
6220 auto-generated <i>`soapServer.cpp`</i> and <i>`soapC.cpp`</i> (or C versions
6221 of those). Compile and link with <b>`-lgsoap++`</b> (<b>`-lgsoap`</b> for
6222 C), or alternatively compile <i>`gsoap/stdsoap2.cpp`</i> (<i>`stdsoap2.c`</i>
6223 for C).
6224
6225 - Use `soap_new()` or `soap_new1(int flags)` to allocate and initialize a
6226 heap-allocated `soap` context with or without flags. Delete this `soap` context with
6227 `soap_free(struct soap*)`, but only after `soap_destroy(struct soap*)` and
6228 `soap_end(struct soap*)`.
6229
6230 - Use `soap_init(struct *soap)` or `soap_init1(struct soap*, int flags)` to
6231 initialize a stack-allocated `soap` context with or without flags. End the use of
6232 this context with `soap_done(struct soap*)`, but only after
6233 `soap_destroy(struct soap*)` and `soap_end(struct soap*)`.
6234
6235 Additional notes with respect to the wsdl2h and soapcpp2 tools:
6236
6237 - Nested classes, structs, and unions in a interface header file are unnested
6238 by soapcpp2.
6239
6240 - Use `#import "file.h"` instead of `#include` to import other header files in
6241 a interface header file for soapcpp2. The `#include`, `#define`, and
6242 `#pragma` are accepted by soapcpp2, but are moved to the very start of the
6243 generated code for the C/C++ compiler to include before all generated
6244 definitions. Often it is useful to add an `#include` with a
6245 [volatile type](#toxsd9-2) that includes the actual type declaration, and to
6246 ensure transient types are declared when these are used in a data binding
6247 interface declared in a interface header file for soapcpp2.
6248
6249 - To remove any SOAP-specific bindings, use <b>`soapcpp2 -0`</b> option <b>`-0`</b>.
6250
6251 - A interface header file for soapcpp2 should not include any code statements,
6252 only data type declarations. This includes constructor initialization lists
6253 that are not permitted. Use member initializations instead.
6254
6255 - C++ namespaces are supported. Use <b>`wsdl2h -qname`</b> option
6256 <b>`-qname`</b> to add C++ namespace `name`. Or add a `namespace name { ... }`
6257 to the header file, but the `{ ... }` must cover the entire
6258 header file content from begin to end.
6259
6260 - Optional XML DOM support can be used to store mixed content or literal XML
6261 content. Otherwise, mixed content may be lost. Use <b>`wsdl2h -d`</b>
6262 option <b>`-d`</b> for XML DOM support and compile and link with
6263 <i>`gsoap/dom.c`</i> or <i>`gsoap/dom.cpp`</i>. For details,
6264 see [XML DOM and XPath](http://www.genivia.com/doc/dom/html).
6265
6266 🔝 [Back to table of contents](#)
6267
6268 Removing SOAP namespaces from XML payloads {#nsmap}
6269 ==========================================
6270
6271 The soapcpp2 tool generates a <i>`.nsmap`</i> file that includes two bindings for SOAP
6272 namespaces. We can remove all SOAP namespaces (and SOAP processing logic) with
6273 <b>`soapcpp2 -0`</b> option <b>`-0`</b> or by simply setting the two entries to NULL:
6274
6275 ~~~{.cpp}
6276 struct Namespace namespaces[] =
6277 {
6278 {"SOAP-ENV", NULL, NULL, NULL},
6279 {"SOAP-ENC", NULL, NULL, NULL},
6280 ...
6281 };
6282 ~~~
6283
6284 Once the <i>`.nsmap`</i> is generated, you can copy-paste the content into your
6285 project code. However, if we rerun wsdl2h on updated WSDL/XSD files or
6286 <i>`typemap.dat`</i> declarations then we need to use the updated table.
6287
6288 In cases that no XML namespaces are used at all, for example with
6289 [XML-RPC](http://www.genivia.com/doc/xml-rpc-json/html), you may use an empty
6290 namespace table:
6291
6292 ~~~{.cpp}
6293 struct Namespace namespaces[] = {{NULL,NULL,NULL,NULL}};
6294 ~~~
6295
6296 However, beware that any built-in xsi attributes that are rendered will lack
6297 the proper namespace binding. At least we suggest to use `SOAP_XML_NOTYPE` for
6298 this reason.
6299
6300 🔝 [Back to table of contents](#)
6301
6302 Examples {#examples}
6303 ========
6304
6305 Select the project files below to peruse the source code examples.
6306
6307 🔝 [Back to table of contents](#)
6308
6309 Source files
6310 ------------
6311
6312 - <i>`address.xsd`</i> Address book schema
6313 - <i>`address.cpp`</i> Address book app (reads/writes address.xml file)
6314 - <i>`addresstypemap.dat`</i> Schema namespace prefix name preference for wsdl2h
6315 - <i>`graph.h`</i> Graph data binding (tree, digraph, cyclic graph)
6316 - <i>`graph.cpp`</i> Test graph serialization as tree, digraph, and cyclic
6317
6318 🔝 [Back to table of contents](#)
6319
6320 Generated files
6321 ---------------
6322
6323 - <i>`address.h`</i> data binding interface generated from address.xsd
6324 - <i>`addressStub.h`</i> C++ data binding definitions
6325 - <i>`addressH.h`</i> Serializers
6326 - <i>`addressC.cpp`</i> Serializers
6327 - <i>`address.xml`</i> Address book data generated by address app
6328 - <i>`graphStub.h`</i> C++ data binding definitions
6329 - <i>`graphH.h`</i> Serializers
6330 - <i>`graphC.cpp`</i> Serializers
6331 - <i>`g.xsd`</i> XSD schema with <i>`g:Graph`</i> complexType
6332 - <i>`g.nsmap`</i> xmlns bindings namespace mapping table
6333
6334 🔝 [Back to table of contents](#)
6335
6336 Build steps
6337 -----------
6338
6339 Building the AddressBook example:
6340
6341 wsdl2h -g -taddresstypemap.dat address.xsd
6342 soapcpp2 -0 -C -S -paddress -I../../import address.h
6343 c++ -I../.. address.cpp addressC.cpp -o address -lgsoap++
6344
6345 Using <b>`wsdl2h -g -taddresstypemap.dat`</b> option <b>`-g`</b> produces
6346 bindings for global (root) elements in addition to types and option
6347 <b>`-taddresstypemap.dat`</b> specifies a mapping file, see further below.
6348
6349 In this case the root element <i>`a:address-book`</i> is bound to `_a__address_book`.
6350 The complexType <i>`a:address`</i> is bound to class `a__address`, which is also the
6351 type of `_a__address_book`. This option is not required, but allows you to use
6352 global element tag names when referring to their serializers, instead of their
6353 type name. Using <b>`soapcpp2 -0 -C -S -paddress`</b> option <b>`-0`</b> removes the
6354 SOAP protocol and the combination of the two options <b>`-C`</b> and
6355 <b>`-S`</b> removes client and server code generation (using option <b>`-C`</b>
6356 alone generates client code and using option <b>`-S`</b> alone generates server
6357 code). Option <b>`-paddress`</b> renames the output <i>`soap`</i>-prefixed files to
6358 <i>`address`</i>-prefixed files.
6359
6360 See the <i>`address.cpp`</i> implementation and [related pages](pages.html).
6361
6362 The <i>`addresstypemap.dat`</i> file specifies the XML namespace prefix for the
6363 bindings:
6364
6365 # Bind the address book schema namespace to prefix 'a'
6366
6367 a = "urn:address-book-example"
6368
6369 # By default the xsd:dateTime schema type is translated to time_t
6370 # To map xsd:dateTime to struct tm, enable the following line:
6371
6372 # xsd__dateTime = #import "../../custom/struct_tm.h"
6373
6374 # ... and compile/link with custom/struct_tm.c
6375
6376 The DOB field is a <i>`xsd:dateTime`</i>, which is bound to `time_t` by default. To
6377 change this to `struct tm`, enable the import of the `xsd__dateTime` custom
6378 serializer by uncommenting the definition of `xsd__dateTime` in
6379 <i>`addresstypemap.dat`</i>. Then change `soap_dateTime2s` to `soap_xsd__dateTime2s`
6380 in the code.
6381
6382 Building the graph serialization example:
6383
6384 soapcpp2 -C -S -pgraph -I../../import graph.h
6385 c++ -I../.. graph.cpp graphC.cpp -o graph -lgsoap++
6386
6387 To compile without using the <b>`-lgsoap++`</b> library: simply compile
6388 <i>`stdsoap2.cpp`</i> together with the above.
6389
6390 🔝 [Back to table of contents](#)
6391
6392 Usage
6393 -----
6394
6395 To execute the AddressBook example:
6396
6397 ./address
6398
6399 To execute the Graph serialization example:
6400
6401 ./graph
6402