Issue #9: Add raw http proxy as an alternative websocket handler

proxy/proxy.go

@@ -44,6 +44,14 @@ func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	var h http.Handler
 	switch {
 	case r.Header.Get("Upgrade") == "websocket":
+		// to establish WS connections as an unfiltered TCP stream
+		// between the client and the server use
+		//
+		//     h = newRawProxy(t.URL)
+		//
+		// This may resolve compatilbility issues between the client
+		// and the server but it also increases the chance for malicious
+		// attacks since fabio no longer acts as a middleman.
 		h = newWSProxy(t.URL)
 	default:
 		h = newHTTPProxy(t.URL, p.tr)

proxy/raw.go

@@ -0,0 +1,58 @@
+package proxy
+
+import (
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"net/url"
+)
+
+// newRawProxy returns an HTTP handler which forwards data between
+// an incoming and outgoing TCP connection including the original request.
+// This handler establishes a new outgoing connection per request.
+func newRawProxy(t *url.URL) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		hj, ok := w.(http.Hijacker)
+		if !ok {
+			http.Error(w, "not a hijacker", http.StatusInternalServerError)
+			return
+		}
+
+		in, _, err := hj.Hijack()
+		if err != nil {
+			log.Printf("[ERROR] Hijack error for %s. %s", r.URL, err)
+			http.Error(w, "hijack error", http.StatusInternalServerError)
+			return
+		}
+		defer in.Close()
+
+		out, err := net.Dial("tcp", t.Host)
+		if err != nil {
+			log.Printf("[ERROR] WS error for %s. %s", r.URL, err)
+			http.Error(w, "error contacting backend server", http.StatusInternalServerError)
+			return
+		}
+		defer out.Close()
+
+		err = r.Write(out)
+		if err != nil {
+			log.Printf("[ERROR] Error copying request for %s. %s", r.URL, err)
+			http.Error(w, "error copying request", http.StatusInternalServerError)
+			return
+		}
+
+		errc := make(chan error, 2)
+		cp := func(dst io.Writer, src io.Reader) {
+			_, err := io.Copy(dst, src)
+			errc <- err
+		}
+
+		go cp(out, in)
+		go cp(in, out)
+		err = <-errc
+		if err != nil && err != io.EOF {
+			log.Printf("[INFO] WS error for %s. %s", r.URL, err)
+		}
+	})
+}