134 lines
3.6 KiB
Go
134 lines
3.6 KiB
Go
// Copyright 2015 beego Author. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain 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,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package context
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import (
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"bytes"
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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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"os"
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"strconv"
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"strings"
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)
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type acceptEncoder struct {
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name string
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encode func(io.Writer, int) (io.Writer, error)
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}
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var (
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noneCompressEncoder = acceptEncoder{"", func(wr io.Writer, level int) (io.Writer, error) { return wr, nil }}
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gzipCompressEncoder = acceptEncoder{"gzip", func(wr io.Writer, level int) (io.Writer, error) { return gzip.NewWriterLevel(wr, level) }}
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deflateCompressEncoder = acceptEncoder{"deflate", func(wr io.Writer, level int) (io.Writer, error) { return flate.NewWriter(wr, level) }}
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)
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var (
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encoderMap = map[string]acceptEncoder{ // all the other compress methods will ignore
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"gzip": gzipCompressEncoder,
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"deflate": deflateCompressEncoder,
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"*": gzipCompressEncoder, // * means any compress will accept,we prefer gzip
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"identity": noneCompressEncoder, // identity means none-compress
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}
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)
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// WriteFile reads from file and writes to writer by the specific encoding(gzip/deflate)
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func WriteFile(encoding string, writer io.Writer, file *os.File) (bool, string, error) {
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return writeLevel(encoding, writer, file, flate.BestCompression)
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}
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// WriteBody reads writes content to writer by the specific encoding(gzip/deflate)
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func WriteBody(encoding string, writer io.Writer, content []byte) (bool, string, error) {
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return writeLevel(encoding, writer, bytes.NewReader(content), flate.BestSpeed)
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}
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// writeLevel reads from reader,writes to writer by specific encoding and compress level
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// the compress level is defined by deflate package
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func writeLevel(encoding string, writer io.Writer, reader io.Reader, level int) (bool, string, error) {
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var outputWriter io.Writer
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var err error
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var ce = noneCompressEncoder
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if cf, ok := encoderMap[encoding]; ok {
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ce = cf
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}
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encoding = ce.name
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outputWriter, err = ce.encode(writer, level)
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if err != nil {
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return false, "", err
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}
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_, err = io.Copy(outputWriter, reader)
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if err != nil {
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return false, "", err
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}
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switch outputWriter.(type) {
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case io.WriteCloser:
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outputWriter.(io.WriteCloser).Close()
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}
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return encoding != "", encoding, nil
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}
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// ParseEncoding will extract the right encoding for response
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// the Accept-Encoding's sec is here:
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// http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
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func ParseEncoding(r *http.Request) string {
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if r == nil {
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return ""
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}
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return parseEncoding(r)
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}
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type q struct {
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name string
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value float64
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}
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func parseEncoding(r *http.Request) string {
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acceptEncoding := r.Header.Get("Accept-Encoding")
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if acceptEncoding == "" {
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return ""
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}
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var lastQ q
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for _, v := range strings.Split(acceptEncoding, ",") {
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v = strings.TrimSpace(v)
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if v == "" {
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continue
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}
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vs := strings.Split(v, ";")
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if len(vs) == 1 {
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lastQ = q{vs[0], 1}
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break
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}
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if len(vs) == 2 {
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f, _ := strconv.ParseFloat(strings.Replace(vs[1], "q=", "", -1), 64)
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if f == 0 {
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continue
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}
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if f > lastQ.value {
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lastQ = q{vs[0], f}
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}
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}
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}
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if cf, ok := encoderMap[lastQ.name]; ok {
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return cf.name
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} else {
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return ""
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}
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}
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