Go Proxy Go

proxy.go

// eg: go run proxy.go -url http://localhost:8443
package main

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

type Prox struct {
	target *url.URL
	proxy  *httputil.ReverseProxy
}

func NewProxy(target string) *Prox {
	url, _ := url.Parse(target)
	return &Prox{target: url, proxy: httputil.NewSingleHostReverseProxy(url)}
}

func (p *Prox) handle(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("X-GoProxy", "GoProxy")
	p.proxy.Transport = &myTransport{}
	p.proxy.ServeHTTP(w, r)
}

type myTransport struct {
}


// func (t *myTransport) RoundTrip(request *http.Request) (*http.Response, error) {

//   buf, _ := ioutil.ReadAll(request.Body)
// 	rdr1 := ioutil.NopCloser(bytes.NewBuffer(buf))
// 	rdr2 := ioutil.NopCloser(bytes.NewBuffer(buf))

// 	fmt.Println("Request body : ", rdr1)
// 	request.Body = rdr2

  
// 	response, err := http.DefaultTransport.RoundTrip(request)
// 	if err != nil {
// 		print("\n\ncame in error resp here", err)
// 		return nil, err //Server is not reachable. Server not working
// 	}
	
// 	body, err := httputil.DumpResponse(response, true)
// 	if err != nil {
// 		print("\n\nerror in dumb response")
// 		// copying the response body did not work
// 		return nil, err
// 	}

// 	log.Println("Response Body : ", string(body))
// 	return response, err
// }

func (t *myTransport) RoundTrip(request *http.Request) (*http.Response, error) {
    body, err := httputil.DumpRequestOut(request, true)
    if err != nil {
        print("What?", err)
        return nil, err
    }

    fmt.Println("Request Body : ", string(body))

    response, err := http.DefaultTransport.RoundTrip(request)
    if err != nil {
        print("\n\ncame in error resp here", err)
        return nil, err //Server is not reachable. Server not working
    }

    // body, err := httputil.DumpResponse(response, true)
    // if err != nil {
    //     print("\n\nerror in dumb response")
    //     // copying the response body did not work
    //     return nil, err
    // }

    log.Println("Response Body : ", string(body))
    return response, err
}

func main() {
	const (
		defaultPort        = ":9090"
		defaultPortUsage   = "default server port, ':9090'"
		defaultTarget      = "http://127.0.0.1:8080"
		defaultTargetUsage = "default redirect url, 'http://127.0.0.1:8080'"
	)

	// flags
	port := flag.String("port", defaultPort, defaultPortUsage)
	redirecturl := flag.String("url", defaultTarget, defaultTargetUsage)

	flag.Parse()

	fmt.Println("server will run on :", *port)
	fmt.Println("redirecting to :", *redirecturl)

	// proxy
	proxy := NewProxy(*redirecturl)

	//http.HandleFunc("/proxyServer", ProxyServer)

	// server redirection
	http.HandleFunc("/", proxy.handle)
	log.Fatal(http.ListenAndServe(*port, nil))
}