Go http包

Go标准库net/http提供完整的HTTP客户端和服务端功能。

HTTP服务端

基本服务器

import "net/http"

func main() {
    // 注册路由
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        w.Write([]byte("Hello World"))
    })

    // 启动服务
    http.ListenAndServe(":8080", nil)
}

HandleFunc注册路由

// 注册处理函数
http.HandleFunc("/hello", helloHandler)
http.HandleFunc("/user", userHandler)

func helloHandler(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("Hello"))
}

func userHandler(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("User"))
}

http.Request请求对象

func handler(w http.ResponseWriter, r *http.Request) {
    // 请求方法
    method := r.Method  // GET, POST, PUT, DELETE

    // 请求路径
    path := r.URL.Path

    // 查询参数
    query := r.URL.Query()
    name := query.Get("name")

    // 请求头
    contentType := r.Header.Get("Content-Type")

    // 请求体
    body, _ := io.ReadAll(r.Body)
    defer r.Body.Close()
}

http.ResponseWriter响应对象

func handler(w http.ResponseWriter, r *http.Request) {
    // 设置响应头
    w.Header().Set("Content-Type", "application/json")

    // 设置状态码
    w.WriteHeader(http.StatusOK)

    // 写入响应体
    w.Write([]byte(`{"status":"ok"}`))
}

// 注意：WriteHeader必须在Write之前调用

HTTP客户端

http.Get请求

// 简单GET请求
resp, err := http.Get("https://api.example.com/data")
if err != nil {
    log.Fatal(err)
}
defer resp.Body.Close()

// 读取响应
body, _ := io.ReadAll(resp.Body)
fmt.Println(string(body))

// 状态码
fmt.Println(resp.StatusCode)

http.Post请求

// POST请求
resp, err := http.Post(
    "https://api.example.com/create",
    "application/json",
    bytes.NewBuffer([]byte(`{"name":"test"}`)),
)
if err != nil {
    log.Fatal(err)
}
defer resp.Body.Close()

自定义请求

// 创建请求对象
req, _ := http.NewRequest("GET", "https://api.example.com/data", nil)

// 设置请求头
req.Header.Set("Authorization", "Bearer token")
req.Header.Set("Content-Type", "application/json")

// 发送请求
client := &http.Client{}
resp, _ := client.Do(req)
defer resp.Body.Close()

超时设置

// 带超时的客户端
client := &http.Client{
    Timeout: 10 * time.Second,
}

resp, _ := client.Get("https://api.example.com/data")

http.Server配置

自定义服务器

server := &http.Server{
    Addr:         ":8080",
    Handler:      nil,           // 使用DefaultServeMux
    ReadTimeout:  10 * time.Second,
    WriteTimeout: 10 * time.Second,
}

server.ListenAndServe()

使用路由器

// 自定义路由器
mux := http.NewServeMux()
mux.HandleFunc("/", homeHandler)
mux.HandleFunc("/api", apiHandler)

server := &http.Server{
    Addr:    ":8080",
    Handler: mux,
}
server.ListenAndServe()

中间件模式

基本中间件

// 日志中间件
func loggingMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        start := time.Now()
        next.ServeHTTP(w, r)
        log.Printf("%s %s %v", r.Method, r.URL.Path, time.Since(start))
    })
}

// 使用中间件
handler := loggingMiddleware(http.HandlerFunc(homeHandler))
http.Handle("/", handler)

链式中间件

// 多个中间件
func chain(h http.Handler, middlewares ...func(http.Handler) http.Handler) http.Handler {
    for _, m := range middlewares {
        h = m(h)
    }
    return h
}

handler := chain(
    http.HandlerFunc(homeHandler),
    loggingMiddleware,
    authMiddleware,
)

常用状态码

const (
    StatusOK                   = 200
    StatusCreated              = 201
    StatusBadRequest           = 400
    StatusUnauthorized        = 401
    StatusForbidden           = 403
    StatusNotFound            = 404
    StatusInternalServerError  = 500
)

// 使用
w.WriteHeader(http.StatusOK)
w.WriteHeader(http.StatusNotFound)

HTTP方法表

静态文件服务

// 文件服务器
fs := http.FileServer(http.Dir("./static"))
http.Handle("/static/", http.StripPrefix("/static/", fs))

// 访问：http://localhost:8080/static/file.txt

JSON响应处理

func jsonHandler(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Content-Type", "application/json")

    data := map[string]string{"message": "hello"}
    json.NewEncoder(w).Encode(data)
}

// JSON请求解析
func createHandler(w http.ResponseWriter, r *http.Request) {
    var data struct {
        Name string `json:"name"`
    }
    json.NewDecoder(r.Body).Decode(&data)
}

优雅关闭

server := &http.Server{Addr: ":8080"}

go func() {
    server.ListenAndServe()
}()

// 监听信号
quit := make(chan os.Signal, 1)
signal.Notify(quit, os.Interrupt)
<-quit

// 优雅关闭
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
server.Shutdown(ctx)

要点总结

• http.HandleFunc注册路由处理函数
• http.Request包含请求信息
• http.ResponseWriter写入响应
• http.Get/Post发送简单请求
• http.NewRequest创建自定义请求
• http.Client配置超时等参数
• 中间件模式实现横切关注点
• http.Server自定义服务器配置
• 静态文件用http.FileServer
• 优雅关闭使用Shutdown方法