traefik/vendor/github.com/emicklei/go-restful/compress.go
2017-03-09 13:13:02 +01:00

88 lines
2.5 KiB
Go

package restful
// Copyright 2013 Ernest Micklei. All rights reserved.
// Use of this source code is governed by a license
// that can be found in the LICENSE file.
import (
"compress/gzip"
"compress/zlib"
"errors"
"io"
"net/http"
"strings"
)
// OBSOLETE : use restful.DefaultContainer.EnableContentEncoding(true) to change this setting.
var EnableContentEncoding = false
// CompressingResponseWriter is a http.ResponseWriter that can perform content encoding (gzip and zlib)
type CompressingResponseWriter struct {
writer http.ResponseWriter
compressor io.WriteCloser
}
// Header is part of http.ResponseWriter interface
func (c *CompressingResponseWriter) Header() http.Header {
return c.writer.Header()
}
// WriteHeader is part of http.ResponseWriter interface
func (c *CompressingResponseWriter) WriteHeader(status int) {
c.writer.WriteHeader(status)
}
// Write is part of http.ResponseWriter interface
// It is passed through the compressor
func (c *CompressingResponseWriter) Write(bytes []byte) (int, error) {
return c.compressor.Write(bytes)
}
// CloseNotify is part of http.CloseNotifier interface
func (c *CompressingResponseWriter) CloseNotify() <-chan bool {
return c.writer.(http.CloseNotifier).CloseNotify()
}
// Close the underlying compressor
func (c *CompressingResponseWriter) Close() {
c.compressor.Close()
}
// WantsCompressedResponse reads the Accept-Encoding header to see if and which encoding is requested.
func wantsCompressedResponse(httpRequest *http.Request) (bool, string) {
header := httpRequest.Header.Get(HEADER_AcceptEncoding)
gi := strings.Index(header, ENCODING_GZIP)
zi := strings.Index(header, ENCODING_DEFLATE)
// use in order of appearance
if gi == -1 {
return zi != -1, ENCODING_DEFLATE
} else if zi == -1 {
return gi != -1, ENCODING_GZIP
} else {
if gi < zi {
return true, ENCODING_GZIP
}
return true, ENCODING_DEFLATE
}
}
// NewCompressingResponseWriter create a CompressingResponseWriter for a known encoding = {gzip,deflate}
func NewCompressingResponseWriter(httpWriter http.ResponseWriter, encoding string) (*CompressingResponseWriter, error) {
httpWriter.Header().Set(HEADER_ContentEncoding, encoding)
c := new(CompressingResponseWriter)
c.writer = httpWriter
var err error
if ENCODING_GZIP == encoding {
w := GzipWriterPool.Get().(*gzip.Writer)
w.Reset(httpWriter)
c.compressor = w
} else if ENCODING_DEFLATE == encoding {
w := ZlibWriterPool.Get().(*zlib.Writer)
w.Reset(httpWriter)
c.compressor = w
} else {
return nil, errors.New("Unknown encoding:" + encoding)
}
return c, err
}