85 lines
1.8 KiB
Go
85 lines
1.8 KiB
Go
// Copyright 2013 The Gorilla Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package handlers
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import (
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"compress/flate"
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"compress/gzip"
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"io"
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"net/http"
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"strings"
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)
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type compressResponseWriter struct {
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io.Writer
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http.ResponseWriter
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http.Hijacker
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}
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func (w *compressResponseWriter) Header() http.Header {
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return w.ResponseWriter.Header()
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}
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func (w *compressResponseWriter) Write(b []byte) (int, error) {
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h := w.ResponseWriter.Header()
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if h.Get("Content-Type") == "" {
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h.Set("Content-Type", http.DetectContentType(b))
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}
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return w.Writer.Write(b)
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}
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// CompressHandler gzip compresses HTTP responses for clients that support it
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// via the 'Accept-Encoding' header.
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func CompressHandler(h http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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L:
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for _, enc := range strings.Split(r.Header.Get("Accept-Encoding"), ",") {
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switch strings.TrimSpace(enc) {
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case "gzip":
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w.Header().Set("Content-Encoding", "gzip")
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w.Header().Add("Vary", "Accept-Encoding")
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gw := gzip.NewWriter(w)
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defer gw.Close()
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h, hok := w.(http.Hijacker)
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if !hok { /* w is not Hijacker... oh well... */
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h = nil
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}
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w = &compressResponseWriter{
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Writer: gw,
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ResponseWriter: w,
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Hijacker: h,
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}
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break L
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case "deflate":
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w.Header().Set("Content-Encoding", "deflate")
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w.Header().Add("Vary", "Accept-Encoding")
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fw, _ := flate.NewWriter(w, flate.DefaultCompression)
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defer fw.Close()
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h, hok := w.(http.Hijacker)
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if !hok { /* w is not Hijacker... oh well... */
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h = nil
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}
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w = &compressResponseWriter{
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Writer: fw,
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ResponseWriter: w,
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Hijacker: h,
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}
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break L
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}
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}
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h.ServeHTTP(w, r)
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})
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}
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