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Beego/acceptencoder/acceptencoder.go
2015-11-10 11:00:29 +08:00

121 lines
3.0 KiB
Go

// Copyright 2015 beego Author. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package acceptencoder
import (
"compress/flate"
"compress/gzip"
"io"
"net/http"
"os"
"strconv"
"strings"
"gopkg.in/bufio.v1"
)
// WriteFile reads from file and writes to writer by the specific encoding(gzip/deflate)
func WriteFile(encoding string, writer io.Writer, file *os.File) (bool, string, error) {
return writeLevel(encoding, writer, file, flate.BestCompression)
}
// WriteBody reads writes content to writer by the specific encoding(gzip/deflate)
func WriteBody(encoding string, writer io.Writer, content []byte) (bool, string, error) {
return writeLevel(encoding, writer, bufio.NewBuffer(content), flate.BestSpeed)
}
// writeLevel reads from reader,writes to writer by specific encoding and compress level
// the compress level is defined by deflate package
func writeLevel(encoding string, writer io.Writer, reader io.Reader, level int) (bool, string, error) {
var outputWriter io.Writer
var err error
switch encoding {
case "gzip":
outputWriter, err = gzip.NewWriterLevel(writer, level)
case "deflate":
outputWriter, err = flate.NewWriter(writer, level)
default:
// all the other compress methods will ignore
// such as the deprecated compress and chrome-only sdch
encoding = ""
outputWriter = writer.(io.Writer)
}
if err != nil {
return false, "", err
}
if _, err = io.Copy(outputWriter, reader); err != nil {
return false, "", err
}
switch outputWriter.(type) {
case io.WriteCloser:
outputWriter.(io.WriteCloser).Close()
}
return encoding != "", encoding, nil
}
// ParseEncoding will extract the right encoding for response
// the Accept-Encoding's sec is here:
// http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
func ParseEncoding(r *http.Request) string {
if r == nil {
return ""
}
return parseEncoding(r)
}
type q struct {
name string
value float64
}
func parseEncoding(r *http.Request) string {
acceptEncoding := r.Header.Get("Accept-Encoding")
if acceptEncoding == "" {
return ""
}
var lastQ q
for _, v := range strings.Split(acceptEncoding, ",") {
v = strings.TrimSpace(v)
if v == "" {
continue
}
vs := strings.Split(v, ";")
if len(vs) == 1 {
lastQ = q{vs[0], 1}
break
}
if len(vs) == 2 {
f, _ := strconv.ParseFloat(strings.Replace(vs[1], "q=", "", -1), 64)
if f == 0 {
continue
}
if f > lastQ.value {
lastQ = q{vs[0], f}
}
}
}
if lastQ.name == "*" {
return "gzip"
}
if lastQ.name == "identity" {
return ""
}
return lastQ.name
}