105 lines
1.9 KiB
Go
105 lines
1.9 KiB
Go
package httpd
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import (
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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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"sync"
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)
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type lazyGzipResponseWriter struct {
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io.Writer
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http.ResponseWriter
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http.Flusher
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http.CloseNotifier
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wroteHeader bool
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}
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// gzipFilter determines if the client can accept compressed responses, and encodes accordingly.
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func gzipFilter(inner http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
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inner.ServeHTTP(w, r)
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return
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}
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gw := &lazyGzipResponseWriter{ResponseWriter: w, Writer: w}
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if f, ok := w.(http.Flusher); ok {
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gw.Flusher = f
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}
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if cn, ok := w.(http.CloseNotifier); ok {
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gw.CloseNotifier = cn
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}
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defer gw.Close()
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inner.ServeHTTP(gw, r)
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})
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}
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func (w *lazyGzipResponseWriter) WriteHeader(code int) {
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if w.wroteHeader {
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return
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}
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w.wroteHeader = true
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if code == http.StatusOK {
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w.Header().Set("Content-Encoding", "gzip")
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// Add gzip compressor
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if _, ok := w.Writer.(*gzip.Writer); !ok {
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w.Writer = getGzipWriter(w.Writer)
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}
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}
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w.ResponseWriter.WriteHeader(code)
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}
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func (w *lazyGzipResponseWriter) Write(p []byte) (int, error) {
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if !w.wroteHeader {
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w.WriteHeader(http.StatusOK)
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}
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return w.Writer.Write(p)
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}
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func (w *lazyGzipResponseWriter) Flush() {
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// Flush writer, if supported
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if f, ok := w.Writer.(interface {
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Flush()
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}); ok {
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f.Flush()
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}
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// Flush the HTTP response
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if w.Flusher != nil {
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w.Flusher.Flush()
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}
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}
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func (w *lazyGzipResponseWriter) Close() error {
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if gw, ok := w.Writer.(*gzip.Writer); ok {
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putGzipWriter(gw)
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}
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return nil
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}
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var gzipWriterPool = sync.Pool{
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New: func() interface{} {
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return gzip.NewWriter(nil)
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},
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}
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func getGzipWriter(w io.Writer) *gzip.Writer {
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gz := gzipWriterPool.Get().(*gzip.Writer)
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gz.Reset(w)
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return gz
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}
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func putGzipWriter(gz *gzip.Writer) {
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gz.Close()
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gzipWriterPool.Put(gz)
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}
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