golang httpリクエスト転送

package main

import (
    "log"
    "net/http"
)

func main() {
    http.HandleFunc("/", handleRequestAndRedirect)
    log.Fatal(http.ListenAndServe(":8080", nil))
}

func handleRequestAndRedirect(w http.ResponseWriter, r *http.Request) {
    url := "http://example.com" + r.URL.Path
    log.Printf("Redirecting to %s", url)

    req, err := http.NewRequest(r.Method, url, r.Body)
    if err != nil {
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }

    // 设置请求头
    for name, values := range r.Header {
        for _, value := range values {
            req.Header.Add(name, value)
        }
    }

    client := http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        http.Error(w, err.Error(), http.StatusBadGateway)
        return
    }
    defer resp.Body.Close()

    // 将响应转发到客户端
    for name, values := range resp.Header {
        for _, value := range values {
            w.Header().Add(name, value)
        }
    }
    w.WriteHeader(resp.StatusCode)
    if _, err := io.Copy(w, resp.Body); err != nil {
        log.Printf("Error copying to client: %v", err)
    }
}