First draft at implementing websocket proxy

cmd/devd/devd.go

@@ -184,7 +184,7 @@ func main() {
 
 	hdrs := make(http.Header)
 	if *cors {
-		hdrs.Set("Access-Control-Allow-Origin", "*")
+		hdrs.Set("Access-Control-Allow-Credentials", "true")
 	}
 
 	var servingScheme string
@@ -196,9 +196,9 @@ func main() {
 
 	dd := devd.Devd{
 		// Shaping
-		Latency:  *latency,
-		DownKbps: *downKbps,
-		UpKbps:   *upKbps,
+		Latency:       *latency,
+		DownKbps:      *downKbps,
+		UpKbps:        *upKbps,
 		ServingScheme: servingScheme,
 
 		AddHeaders: &hdrs,
@@ -209,6 +209,8 @@ func main() {
 		WatchPaths:       *watch,
 		Excludes:         *excludes,
 
+		Cors: *cors,
+
 		Credentials: creds,
 	}
 

httpctx/httpctx.go

@@ -47,3 +47,14 @@ func StripPrefix(prefix string, h Handler) Handler {
 		}
 	})
 }
+
+func RouteWebsockets(httpHandler, wsHandler Handler) Handler {
+	return HandlerFunc(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+		upgrade := r.Header.Get("Upgrade")
+		if upgrade == "websocket" {
+			wsHandler.ServeHTTPContext(ctx, w, r)
+		} else {
+			httpHandler.ServeHTTPContext(ctx, w, r)
+		}
+	})
+}

responselogger.go

@@ -1,7 +1,9 @@
 package devd
 
 import (
+	"bufio"
 	"fmt"
+	"net"
 	"net/http"
 	"strconv"
 
@@ -15,6 +17,7 @@ import (
 type ResponseLogWriter struct {
 	Log         termlog.Logger
 	Resp        http.ResponseWriter
+	Hijacker    http.Hijacker
 	Flusher     http.Flusher
 	Timer       *timer.Timer
 	wroteHeader bool
@@ -87,3 +90,6 @@ func (rl *ResponseLogWriter) Flush() {
 		rl.Flusher.Flush()
 	}
 }
+func (rl *ResponseLogWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return rl.Hijacker.Hijack()
+}

route.go

@@ -14,6 +14,8 @@ import (
 	"github.com/cortesi/devd/inject"
 	"github.com/cortesi/devd/reverseproxy"
 	"github.com/cortesi/devd/routespec"
+	"github.com/cortesi/devd/websocketproxy"
+	"github.com/gorilla/websocket"
 )
 
 // Endpoint is the destination of a Route - either on the filesystem or
@@ -33,7 +35,20 @@ func (ep forwardEndpoint) Handler(prefix string, templates *template.Template, c
 		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
 	}
 	rp.FlushInterval = 200 * time.Millisecond
-	return httpctx.StripPrefix(prefix, rp)
+
+	wsURL := url.URL(ep)
+	switch wsURL.Scheme {
+	case "http":
+		wsURL.Scheme = "ws"
+	case "https":
+		wsURL.Scheme = "wss"
+	}
+	ws := websocketproxy.NewProxy(&wsURL)
+	ws.Dialer = &websocket.Dialer{
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+	}
+
+	return httpctx.StripPrefix(prefix, httpctx.RouteWebsockets(rp, ws))
 }
 
 func newForwardEndpoint(path string) (*forwardEndpoint, error) {

server.go

@@ -151,6 +151,9 @@ type Devd struct {
 	WatchPaths []string
 	Excludes   []string
 
+	// Add Access-Control-Allow-Origin header
+	Cors bool
+
 	// Logging
 	IgnoreLogs []*regexp.Regexp
 
@@ -194,10 +197,22 @@ func (dd *Devd) WrapHandler(log termlog.TermLog, next httpctx.Handler) http.Hand
 				}
 			}
 		}
+		if dd.Cors {
+			origin := r.Header.Get("Origin")
+			if origin == "" {
+				origin = "*"
+			}
+			w.Header().Set("Access-Control-Allow-Origin", origin)
+			requestHeaders := r.Header.Get("Access-Control-Request-Headers")
+			if requestHeaders != "" {
+				w.Header().Set("Access-Control-Allow-Headers", requestHeaders)
+			}
+		}
 		flusher, _ := w.(http.Flusher)
+		hijacker, _ := w.(http.Hijacker)
 		next.ServeHTTPContext(
 			ctx,
-			&ResponseLogWriter{Log: sublog, Resp: w, Flusher: flusher, Timer: &timr},
+			&ResponseLogWriter{Log: sublog, Resp: w, Hijacker: hijacker, Flusher: flusher, Timer: &timr},
 			r,
 		)
 	})

websocketproxy/.travis.yml

@@ -0,0 +1,2 @@
+language: go
+go: 1.8

websocketproxy/LICENSE.md

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Koding, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

websocketproxy/README.md

@@ -0,0 +1,54 @@
+# WebsocketProxy [![GoDoc](https://godoc.org/github.com/koding/websocketproxy?status.svg)](https://godoc.org/github.com/koding/websocketproxy) [![Build Status](https://travis-ci.org/koding/websocketproxy.svg)](https://travis-ci.org/koding/websocketproxy)
+
+WebsocketProxy is an http.Handler interface build on top of
+[gorilla/websocket](https://github.com/gorilla/websocket) that you can plug
+into your existing Go webserver to provide WebSocket reverse proxy.
+
+## Install
+
+```bash
+go get github.com/koding/websocketproxy
+```
+
+## Example
+
+Below is a simple server that proxies to the given backend URL
+
+```go
+package main
+
+import (
+	"flag"
+	"net/http"
+	"net/url"
+
+	"github.com/koding/websocketproxy"
+)
+
+var (
+	flagBackend = flag.String("backend", "", "Backend URL for proxying")
+)
+
+func main() {
+	u, err := url.Parse(*flagBackend)
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	err = http.ListenAndServe(":80", websocketproxy.NewProxy(u))
+	if err != nil {
+		log.Fatalln(err)
+	}
+}
+```
+
+Save it as `proxy.go` and run as:
+
+```bash
+go run proxy.go -backend ws://example.com:3000
+```
+
+Now all incoming WebSocket requests coming to this server will be proxied to
+`ws://example.com:3000`
+
+