Handle external upgrade for all websocket proxies (#843)

* Upgrade websocket proxies without initial http request
* Add websocket upgrade proxy test.

lib/Server.js

@@ -127,6 +127,9 @@ function Server(compiler, options) {
 		contentBase = process.cwd();
 	}
 
+	// Keep track of websocket proxies for external websocket upgrade.
+	const websocketProxies = [];
+
 	const features = {
 		compress() {
 			if(options.compress) {
@@ -205,6 +208,9 @@ function Server(compiler, options) {
 					}
 
 					proxyMiddleware = getProxyMiddleware(proxyConfig);
+					if(proxyConfig.ws) {
+						websocketProxies.push(proxyMiddleware);
+					}
 
 					app.use((req, res, next) => {
 						if(typeof proxyConfigOrCallback === "function") {
@@ -361,6 +367,12 @@ function Server(compiler, options) {
 	} else {
 		this.listeningApp = http.createServer(app);
 	}
+
+	// Proxy websockets without the initial http request
+	// https://github.com/chimurai/http-proxy-middleware#external-websocket-upgrade
+	websocketProxies.forEach(function(wsProxy) {
+		this.listeningApp.on("upgrade", wsProxy.upgrade);
+	}, this);
 }
 
 Server.prototype.use = function() {

package.json

@@ -43,7 +43,8 @@
     "style-loader": "~0.13.0",
     "supertest": "^2.0.1",
     "url-loader": "~0.5.6",
-    "webpack": "^2.2.0"
+    "webpack": "^2.2.0",
+    "ws": "^1.1.1"
   },
   "license": "MIT",
   "repository": {

test/Proxy.test.js

@@ -3,9 +3,12 @@
 const request = require("supertest");
 const path = require("path");
 const express = require("express");
+const WebSocket = require("ws");
 const helper = require("./helper");
+const should = require("should");
 const config = require("./fixtures/proxy-config/webpack.config");
 
+const WebSocketServer = WebSocket.Server;
 const contentBase = path.join(__dirname, "fixtures/proxy-config");
 
 const proxyOption = {
@@ -184,4 +187,48 @@ describe("Proxy", function() {
 			req.get("/proxy2").expect(200, "from proxy", done);
 		});
 	});
+
+	context("External websocket upgrade", function() {
+		let ws;
+		let wsServer;
+		let responseMessage;
+
+		before(function(done) {
+			helper.start(config, {
+				contentBase,
+				proxy: [{
+					context: "/",
+					target: "http://localhost:9003",
+					ws: true
+				}]
+			}, done);
+
+			wsServer = new WebSocketServer({ port: 9003 });
+			wsServer.on("connection", function connection(ws) {
+				ws.on("message", function incoming(message) {
+					ws.send(message);
+				});
+			});
+		});
+
+		beforeEach(function(done) {
+			ws = new WebSocket("ws://localhost:8080/proxy3/socket");
+			ws.on("message", function(message) {
+				responseMessage = message;
+				done()
+			});
+			ws.on("open", function open() {
+				ws.send("foo");
+			});
+		})
+
+		it("Should receive response", function() {
+			should(responseMessage).equal("foo");
+		});
+
+		after(function(done) {
+			wsServer.close();
+			helper.close(done);
+		});
+	});
 });