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122 lines
3.4 KiB
122 lines
3.4 KiB
// Copyright 2013 Martini Authors
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// Copyright 2015 The Macaron Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License"): you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations
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// under the License.
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package gzip
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import (
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"bufio"
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"fmt"
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"net"
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"net/http"
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"strings"
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"github.com/klauspost/compress/gzip"
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"gopkg.in/macaron.v1"
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)
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const (
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_HEADER_ACCEPT_ENCODING = "Accept-Encoding"
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_HEADER_CONTENT_ENCODING = "Content-Encoding"
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_HEADER_CONTENT_LENGTH = "Content-Length"
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_HEADER_CONTENT_TYPE = "Content-Type"
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_HEADER_VARY = "Vary"
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)
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// Options represents a struct for specifying configuration options for the GZip middleware.
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type Options struct {
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// Compression level. Can be DefaultCompression(-1), ConstantCompression(-2)
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// or any integer value between BestSpeed(1) and BestCompression(9) inclusive.
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CompressionLevel int
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}
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func isCompressionLevelValid(level int) bool {
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return level == gzip.DefaultCompression ||
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level == gzip.ConstantCompression ||
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(level >= gzip.BestSpeed && level <= gzip.BestCompression)
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}
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func prepareOptions(options []Options) Options {
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var opt Options
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if len(options) > 0 {
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opt = options[0]
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}
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if !isCompressionLevelValid(opt.CompressionLevel) {
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// For web content, level 4 seems to be a sweet spot.
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opt.CompressionLevel = 4
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}
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return opt
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}
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// Gziper returns a Handler that adds gzip compression to all requests.
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// Make sure to include the Gzip middleware above other middleware
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// that alter the response body (like the render middleware).
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func Gziper(options ...Options) macaron.Handler {
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opt := prepareOptions(options)
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return func(ctx *macaron.Context) {
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if !strings.Contains(ctx.Req.Header.Get(_HEADER_ACCEPT_ENCODING), "gzip") {
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return
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}
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headers := ctx.Resp.Header()
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headers.Set(_HEADER_CONTENT_ENCODING, "gzip")
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headers.Set(_HEADER_VARY, _HEADER_ACCEPT_ENCODING)
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// We've made sure compression level is valid in prepareGzipOptions,
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// no need to check same error again.
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gz, err := gzip.NewWriterLevel(ctx.Resp, opt.CompressionLevel)
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if err != nil {
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panic(err.Error())
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}
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defer gz.Close()
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gzw := gzipResponseWriter{gz, ctx.Resp}
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ctx.Resp = gzw
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ctx.MapTo(gzw, (*http.ResponseWriter)(nil))
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// Check if render middleware has been registered,
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// if yes, we need to modify ResponseWriter for it as well.
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if _, ok := ctx.Render.(*macaron.DummyRender); !ok {
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ctx.Render.SetResponseWriter(gzw)
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}
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ctx.Next()
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// delete content length after we know we have been written to
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gzw.Header().Del("Content-Length")
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}
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}
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type gzipResponseWriter struct {
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w *gzip.Writer
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macaron.ResponseWriter
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}
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func (grw gzipResponseWriter) Write(p []byte) (int, error) {
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if len(grw.Header().Get(_HEADER_CONTENT_TYPE)) == 0 {
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grw.Header().Set(_HEADER_CONTENT_TYPE, http.DetectContentType(p))
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}
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return grw.w.Write(p)
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}
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func (grw gzipResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
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hijacker, ok := grw.ResponseWriter.(http.Hijacker)
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if !ok {
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return nil, nil, fmt.Errorf("the ResponseWriter doesn't support the Hijacker interface")
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}
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return hijacker.Hijack()
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}
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