go写的http工具

go build reverseProxy.go
reverseProxy http://192.168.50.148:12321
2024/08/15 15:14:47 program start......
2024/08/15 15:14:47 listen http proxy on :8001.....
浏览器中输入：http://127.0.0.1:8001/，即可访问指定网站，并打印http请求与返回数据包。


package main

import (
"bytes"
"fmt"
"log"
"io/ioutil"
"net/http"
"net/http/httputil"
"net/url"
"os"
)

type transport struct {
http.RoundTripper
}

func (t *transport) RoundTrip(req *http.Request) (resp *http.Response, err error) {
// 获取请求报文的内容长度
len := req.ContentLength
if(len > 0){
log.Println("req.ContentLength", len)
b1, err1 := ioutil.ReadAll(req.Body)
if err1 != nil {
fmt.Println(err1.Error())
return nil, err1
}else{
fmt.Println(string(b1))
}

err1 = req.Body.Close()
if err1 != nil {
return nil, err1
}

// 重新生成可读取的
body1 := ioutil.NopCloser(bytes.NewReader(b1))
req.Body = body1
}

resp, err = t.RoundTripper.RoundTrip(req)
if err != nil {
return nil, err
}

b, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}

err = resp.Body.Close()
if err != nil {
return nil, err
}

log.Println("resp.ContentLength", resp.ContentLength)
fmt.Println(string(b))

//读取响应并修改响应
b = bytes.Replace(b, []byte("Google"), []byte("GOOGLE"), -1)
body := ioutil.NopCloser(bytes.NewReader(b))
resp.Body = body
return resp, nil
}

func sameHost(handler http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
r.Host = r.URL.Host
handler.ServeHTTP(w, r)
})
}

func main() {
var sz string
if(len(os.Args)<2){
fmt.Printf("请输入url：")//http://127.0.0.1:80 or http://192.168.50.148:12321
fmt.Scanf("%s",&sz)
}else{
sz=os.Args[1]
}
targetURL, err := url.Parse(sz)
log.Println("program start......")
if err != nil {
log.Println("bad url:", err)
return
}
reverseProxy := httputil.NewSingleHostReverseProxy(targetURL)
//http.HandleFunc("/myinfo/", httpUserInfo)
//http.Handle("/", reverseProxy)
reverseProxy.Transport = &transport{http.DefaultTransport}
// wrap that proxy with our sameHost function
singleHosted := sameHost(reverseProxy)
log.Println("listen http proxy on :8001.....")
http.ListenAndServe(":8001", singleHosted)
//http.ListenAndServe(":8001", nil)
}