add basic ws functionality

lib/modules/webserver/backend/index.html

@@ -1 +1,29 @@
 Welcome to Embark!
+
+<script>
+
+var ws = new WebSocket("ws://localhost:8000/logs");
+
+ws.onopen = function() {
+  // Web Socket is connected, send data using send()
+  ws.send("Message to send");
+  alert("Message is sent...");
+};
+
+ws.onmessage = function (evt) {
+  var received_msg = evt.data;
+  console.log(received_msg);
+  //alert("Message is received...");
+};
+
+ws.onclose = function() {
+  // websocket is closed.
+  alert("Connection is closed...");
+};
+
+window.onbeforeunload = function(event) {
+  socket.close();
+};
+
+</script>
+

lib/modules/webserver/server.js

@@ -7,6 +7,7 @@ const fs = require('../../core/fs');
 require('http-shutdown').extend();
 var express = require('express');
 let path = require('path');
+var expressWebSocket = require('express-ws');
 
 class Server {
   constructor(options) {
@@ -64,19 +65,31 @@ class Server {
     this.app.use('/coverage', coverage);
     this.app.use(coverageStyle);
 
-    this.app.ws('/', (_ws, _req) => {});
-    const wss = expressWs.getWss('/');
+    expressWebSocket(this.app);
 
+    this.app.ws('/logs', function(ws, req) {
+      self.events.on("log", function(logLevel, logMsg) {
+        console.dir("got message " + logMsg);
+        ws.send(logMsg);
+      });
+      ws.on('message', function(msg) {
+        console.dir("got message");
+        console.dir(msg);
+        ws.send(msg);
+      });
+    });
+
+    this.app.ws('/', function(ws, _req) {
       self.events.on('outputDone', () => {
-      wss.clients.forEach(function (client) {
-        client.send('outputDone');
+        if (ws.readyState === WEB_SOCKET_STATE_OPEN) {
+          return ws.send('outputDone');
+        }
+        // if the socket wasn't yet opened, listen for the 'open' event,
+        // then send the 'outputDone' data
+        ws.addEventListener('open', _event => {
+          ws.send('outputDone');
         });
       });
-
-    self.events.on('outputError', () => {
-      wss.clients.forEach(function (client) {
-        client.send('outputError');
-      });
     });
 
     async.waterfall([

package.json

@@ -74,6 +74,7 @@
     "i18n": "0.8.3",
 =======
     "express": "^4.16.2",
+    "express-ws": "^3.0.0",
     "file-loader": "^1.1.5",
     "finalhandler": "^1.1.1",
     "follow-redirects": "^1.2.4",