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@tobychui
Created February 17, 2021 02:59
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Golang gzip middleware module
package gzipmiddleware
import (
"compress/gzip"
"io"
"io/ioutil"
"net/http"
"strings"
"sync"
)
/*
This module handles gzip on http.Handler and http.HandleFunc
author: tobychui
*/
var gzPool = sync.Pool{
New: func() interface{} {
w := gzip.NewWriter(ioutil.Discard)
gzip.NewWriterLevel(w, gzip.BestCompression)
return w
},
}
type gzipResponseWriter struct {
io.Writer
http.ResponseWriter
}
func (w *gzipResponseWriter) WriteHeader(status int) {
w.Header().Del("Content-Length")
w.ResponseWriter.WriteHeader(status)
}
func (w *gzipResponseWriter) Write(b []byte) (int, error) {
return w.Writer.Write(b)
}
/*
Compresstion function for http.FileServer
*/
func Compress(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
h.ServeHTTP(w, r)
return
}
w.Header().Set("Content-Encoding", "gzip")
gz := gzPool.Get().(*gzip.Writer)
defer gzPool.Put(gz)
gz.Reset(w)
defer gz.Close()
h.ServeHTTP(&gzipResponseWriter{ResponseWriter: w, Writer: gz}, r)
})
}
type gzipFuncResponseWriter struct {
io.Writer
http.ResponseWriter
}
func (w gzipFuncResponseWriter) Write(b []byte) (int, error) {
return w.Writer.Write(b)
}
/*
Compress Function for http.HandleFunc
*/
func CompressFunc(fn http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
fn(w, r)
return
}
w.Header().Set("Content-Encoding", "gzip")
gz := gzip.NewWriter(w)
defer gz.Close()
gzr := gzipFuncResponseWriter{Writer: gz, ResponseWriter: w}
fn(gzr, r)
}
}
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