如何使用gzip压缩http.FileServer内容？

Question

我使用http.FileServer作为静态服务器，但我想使用gzip压缩

现在的代码：

    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {

        // Static file route

        handle := http.FileServer(http.Dir("resource/dist"))
        w.Header().Set("Content-Encoding", "gzip")

        // ??? use gzip here?

        handle.ServeHTTP(w, r)
    })

并且响应头包含gzip。

HTTP/1.1 200 OK
Accept-Ranges: bytes
Content-Encoding: gzip
Content-Type: text/html; charset=utf-8
Last-Modified: Tue, 28 Apr 2020 12:06:15 GMT
Date: Tue, 28 Apr 2020 16:39:40 GMT
Content-Length: 687

那么如何在这里使用gzip包呢？

谢谢

Answer 1

net/http没有内置的gzip传输，需要使用第三方库来实现。

https://github.com/nytimes/gziphandler

package main

import (
    "io"
    "net/http"
    "github.com/NYTimes/gziphandler"
)

func main() {
    withoutGz := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        w.Header().Set("Content-Type", "text/plain")
        io.WriteString(w, "Hello, World")
    })

    withGz := gziphandler.GzipHandler(withoutGz)

    http.Handle("/", withGz)
    http.ListenAndServe("0.0.0.0:8000", nil)
}

Answer 2

我根据the42 CJEnright的各种要点编写了这段代码

package main

import (
    "compress/gzip"
    "io"
    "io/ioutil"
    "net/http"
    "strings"
    "sync"
)

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)
}

// Gzip func handler
func Gzip(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
            next.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()

       next.ServeHTTP(&gzipResponseWriter{ResponseWriter: w, Writer: gz}, r)
    })
}

func main() {
    println("Starting on http://localhost:8080")
    http.ListenAndServe(":8080", Gzip(http.FileServer(http.Dir(`.`))))
}