use uWS as optional dependency for ws server (#3231)

* use uWS as optional dependency for ws server

* Update ParseWebSocketServer.js

package.json

@@ -84,6 +84,7 @@
     "parse-server": "./bin/parse-server"
   },
   "optionalDependencies": {
-    "bcrypt": "1.0.2"
+    "bcrypt": "1.0.2",
+    "uws": "^0.12.0"
   }
 }

spec/ParseWebSocketServer.spec.js

@@ -14,7 +14,9 @@ describe('ParseWebSocketServer', function() {
 
   it('can handle connect event when ws is open', function(done) {
     var onConnectCallback = jasmine.createSpy('onConnectCallback');
-    var parseWebSocketServer = new ParseWebSocketServer({}, onConnectCallback, 5).server;
+    var http = require('http');
+    var server = http.createServer();
+    var parseWebSocketServer = new ParseWebSocketServer(server, onConnectCallback, 5).server;
     var ws = {
       readyState: 0,
       OPEN: 0,
@@ -27,6 +29,7 @@ describe('ParseWebSocketServer', function() {
     // Make sure we ping to the client
     setTimeout(function() {
       expect(ws.ping).toHaveBeenCalled();
+      server.close();
       done();
     }, 10)
   });

src/LiveQuery/ParseWebSocketServer.js

@@ -1,12 +1,19 @@
 import logger from '../logger';
 
 const typeMap = new Map([['disconnect', 'close']]);
+const getWS = function() {
+  try {
+    return require('uws');
+  } catch(e) {
+    return require('ws');
+  }
+}
 
 export class ParseWebSocketServer {
   server: Object;
 
   constructor(server: any, onConnect: Function, websocketTimeout: number = 10 * 1000) {
-    const WebSocketServer = require('ws').Server;
+    const WebSocketServer = getWS().Server;
     const wss = new WebSocketServer({ server: server });
     wss.on('listening', () => {
       logger.info('Parse LiveQuery Server starts running');