88 lines
1.9 KiB
Go
88 lines
1.9 KiB
Go
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package http
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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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"unicode"
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"git.loafle.net/commons_go/rpc/encode"
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)
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// gzipWriter writes and closes the gzip writer.
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type gzipWriter struct {
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w *gzip.Writer
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}
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func (gw *gzipWriter) Write(p []byte) (n int, err error) {
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defer gw.w.Close()
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return gw.w.Write(p)
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}
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// gzipEncoder implements the gzip compressed http encoder.
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type gzipEncoder struct {
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}
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func (enc *gzipEncoder) Encode(w http.ResponseWriter) io.Writer {
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w.Header().Set("Content-Encoding", "gzip")
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return &gzipWriter{gzip.NewWriter(w)}
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}
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// flateWriter writes and closes the flate writer.
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type flateWriter struct {
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w *flate.Writer
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}
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func (fw *flateWriter) Write(p []byte) (n int, err error) {
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defer fw.w.Close()
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return fw.w.Write(p)
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}
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// flateEncoder implements the flate compressed http encoder.
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type flateEncoder struct {
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}
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func (enc *flateEncoder) Encode(w http.ResponseWriter) io.Writer {
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fw, err := flate.NewWriter(w, flate.DefaultCompression)
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if err != nil {
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return w
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}
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w.Header().Set("Content-Encoding", "deflate")
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return &flateWriter{fw}
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}
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// CompressionSelector generates the compressed http encoder.
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type CompressionSelector struct {
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}
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// acceptedEnc returns the first compression type in "Accept-Encoding" header
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// field of the request.
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func acceptedEnc(req *http.Request) string {
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encHeader := req.Header.Get("Accept-Encoding")
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if encHeader == "" {
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return ""
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}
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encTypes := strings.FieldsFunc(encHeader, func(r rune) bool {
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return unicode.IsSpace(r) || r == ','
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})
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for _, enc := range encTypes {
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if enc == "gzip" || enc == "deflate" {
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return enc
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}
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}
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return ""
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}
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// Select method selects the correct compression encoder based on http HEADER.
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func (_ *CompressionSelector) Select(r *http.Request) Encoder {
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switch acceptedEnc(r) {
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case "gzip":
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return &gzipEncoder{}
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case "flate":
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return &flateEncoder{}
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}
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return encode.DefaultEncoder
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}
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