proxy.go

proxy.go

package main

import (
	"crypto/tls"
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
	"time"
)

func handleTunneling(w http.ResponseWriter, r *http.Request) {
	destConn, err := net.DialTimeout("tcp", r.Host, 10*time.Second)
	if err != nil {
		http.Error(w, err.Error(), http.StatusServiceUnavailable)
		return
	}
	w.WriteHeader(http.StatusOK)
	hijacker, ok := w.(http.Hijacker)
	if !ok {
		http.Error(w, "Hijacking not supported", http.StatusInternalServerError)
		return
	}
	clientConn, _, err := hijacker.Hijack()
	if err != nil {
		http.Error(w, err.Error(), http.StatusServiceUnavailable)
	}
	go transfer(destConn, clientConn)
	go transfer(clientConn, destConn)
}

func transfer(destination io.WriteCloser, source io.ReadCloser) {
	defer destination.Close()
	defer source.Close()
	io.Copy(destination, source)
}

func handleHTTP(w http.ResponseWriter, req *http.Request) {
	resp, err := http.DefaultTransport.RoundTrip(req)
	if err != nil {
		http.Error(w, err.Error(), http.StatusServiceUnavailable)
		return
	}
	defer resp.Body.Close()
	copyHeader(w.Header(), resp.Header)
	w.WriteHeader(resp.StatusCode)
	io.Copy(w, resp.Body)
}

func copyHeader(dst, src http.Header) {
	for k, vv := range src {
		for _, v := range vv {
			dst.Add(k, v)
		}
	}
}

func main() {
	server := &http.Server{
		Addr: ":8888",
		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			fmt.Printf("Req: %+v %s\n", r.URL, r.URL.Path)
			fmt.Println("GET params were:", r.URL.Query())

			if r.Method == http.MethodConnect {
				handleTunneling(w, r)
			} else {
				handleHTTP(w, r)
			}
		}),
		// Disable HTTP/2.
		TLSNextProto: make(map[string]func(*http.Server, *tls.Conn, http.Handler)),
	}

	log.Fatal(server.ListenAndServe())
}

fmt.Sprintf("%s://%s%s", r.URL.Scheme, r.Host, r.RequestURI())

@iamwavecut Thank you for suggestion. fmt.Printf("%s://%s%s", r.URL.Scheme, r.Host, r.RequestURI)
This is what it outputs

://www.youtube.com:443www.youtube.com:443