Go 标准库 http.FileServer 实现静态文件服务

http.FileServer

net/http

http.ListenAndServe(":8080", http.FileServer(http.Dir("/files/path")))

访问

http://127.0.0.1:8080

autoindex

源码解析

我们现在开始将上述的那仅有的一行代码进行剖析，看看到底是如何实现的。源码中英文注释也比较详细，可以参考。

我们先看

http.Dir()

http.FileServer()

http.ListenAndServe()

http.Dir()

从以下源码我们可以看出，

type Dir string

type FileSystem interface

Open

http.Dir("/")

http.Dir

// 所属文件: src/net/http/fs.go, 26-87行

type Dir string

func (d Dir) Open(name string) (File, error) {
// ...
}

type FileSystem interface {
Open(name string) (File, error)
}

http.FileServer()

http.FileServer()

fileHandler

fileHandler

Handler

ServeHTTP()

ServeHTTP

serveFile()

// 所属文件: src/net/http/fs.go, 690-716行

type fileHandler struct {
root FileSystem
}

func FileServer(root FileSystem) Handler {
return &fileHandler{root}
}

func (f *fileHandler) ServeHTTP(w ResponseWriter, r *Request) {
upath := r.URL.Path
if !strings.HasPrefix(upath, "/") {
upath = "/" + upath
r.URL.Path = upath
}
serveFile(w, r, f.root, path.Clean(upath), true)
}

// 所属文件: src/net/http/server.go, 82行

type Handler interface {
ServeHTTP(ResponseWriter, *Request)
}

serveFile()

serveContent()

serveContent()

// 所属文件: src/net/http/fs.go, 540行

// name is '/'-separated, not filepath.Separator.
func serveFile(w ResponseWriter, r *Request, fs FileSystem, name string, redirect bool) {

// 中间代码已省略

if d.IsDir() {
if checkIfModifiedSince(r, d.ModTime()) == condFalse {
writeNotModified(w)
return
}
w.Header().Set("Last-Modified", d.ModTime().UTC().Format(TimeFormat))
dirList(w, r, f)
return
}

// serveContent will check modification time
sizeFunc := func() (int64, error) { return d.Size(), nil }
serveContent(w, r, d.Name(), d.ModTime(), sizeFunc, f)
}

支持子目录路径

http.StripPrefix()

http.Handle()

http.HandleFunc()

package main

import (
"net/http"
"fmt"
)

func main() {

http.Handle("/tmpfiles/", http.StripPrefix("/tmpfiles/", http.FileServer(http.Dir("/tmp"))))

err := http.ListenAndServe(":8080", nil)
if err != nil {
fmt.Println(err)
}

}