Go reverse proxy

reverse_proxy.go

package main

import (
	"fmt"
	"net/http"
	"net/http/httputil"
	"net/url"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		baseURL, err := url.Parse("http://127.0.0.1:3999")
		if err != nil {
			panic(err)
		}

		proxy := httputil.NewSingleHostReverseProxy(&url.URL{
			Scheme: baseURL.Scheme,
			Host:   baseURL.Host,
		})

		req := r
		req.URL.Scheme = baseURL.Scheme
		req.URL.Host = baseURL.Host
		req.Host = baseURL.Host

		fmt.Println(">", req.URL)

		proxy.ServeHTTP(w, req)
	})

	if err := http.ListenAndServe(":80", nil); err != nil {
		panic(err)
	}
}