如何在Go语言中实现路由中间件

go get -u GitHub.com/gorilla/mux

package main

import (
    "fmt"
    "net/Http"

    "github.com/gorilla/mux"
)

func middleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // 在请求到达目标处理函数之前执行的操作
        
        fmt.Println("Executing middleware")

        // 调用下一个中间件或目标处理函数
        next.ServeHTTP(w, r)
    })
}

func main() {
    r := mux.NewRouter()

    // 使用我们的中间件
    r.Use(middleware)

    // 路由定义
    r.HandleFunc("/", homeHandler).Methods("GET")

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

func homeHandler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "Hello, World!")
}

package main

import (
    "fmt"
    "log"
    "net/http"
)

type MyHandler struct{}

func (h *MyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    fmt.Println("Executing middleware")
    // 调用目标处理函数
    homeHandler(w, r)
}

func middleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // 在请求到达目标处理函数之前执行的操作
        fmt.Println("Executing middleware")
        next.ServeHTTP(w, r)
    })
}

func main() {
    mux := http.NewServeMux()

    // 创建中间件
    handler := middleware(&MyHandler{})

    // 设置路由
    mux.Handle("/", handler)

    // 启动服务器
    log.Fatal(http.ListenAndServe(":8080", mux))
}

func homeHandler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "Hello, World!")
}