at least it works

medium/sample.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"flag"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"time"
+)
+
+func handleTunneling(w http.ResponseWriter, r *http.Request) {
+	dest_conn, 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
+	}
+	client_conn, _, err := hijacker.Hijack()
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusServiceUnavailable)
+	}
+	go transfer(dest_conn, client_conn)
+	go transfer(client_conn, dest_conn)
+}
+
+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() {
+	var pemPath string
+	flag.StringVar(&pemPath, "pem", "server.crt", "path to pem file")
+	var keyPath string
+	flag.StringVar(&keyPath, "key", "server.key", "path to key file")
+	var proto string
+	flag.StringVar(&proto, "proto", "https", "Proxy protocol (http or https)")
+	flag.Parse()
+
+	if proto != "http" && proto != "https" {
+		log.Fatal("Protocol must be either http or https")
+	}
+
+	server := &http.Server{
+		Addr: ":8888",
+		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			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)),
+	}
+
+	if proto == "http" {
+		log.Fatal(server.ListenAndServe())
+	} else {
+		log.Fatal(server.ListenAndServeTLS(pemPath, keyPath))
+	}
+}