more

main.go

@@ -22,6 +22,14 @@ func transfer(dst io.WriteCloser, src io.ReadCloser) {
 	io.Copy(dst, src)
 }
 
+func copyHeader(dst, src http.Header) {
+	for k, vv := range src {
+		for _, v := range vv {
+			dst.Add(k, v)
+		}
+	}
+}
+
 func (h *httpProxyHandler) dialOut(addr string) (net.Conn, error) {
 	host, _, err := net.SplitHostPort(addr)
 	if err != nil {
@@ -56,6 +64,15 @@ func (h *httpProxyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		go transfer(conn, outConn)
 		go transfer(outConn, conn)
 	} else {
+		resp, err := http.DefaultTransport.RoundTrip(r)
+		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)
 		w.WriteHeader(http.StatusMethodNotAllowed)
 	}
 }