feat: add WebSockets client and server

package.json

@@ -29,6 +29,7 @@
   "dependencies": {
     "express": "^4.16.4",
     "express-jwt": "^5.3.1",
+    "express-ws": "^4.0.0",
     "get-port": "^4.0.0",
     "reflect-metadata": "^0.1.12"
   },
@@ -39,6 +40,7 @@
     "@semantic-release/npm": "^5.0.5",
     "@semantic-release/release-notes-generator": "^7.1.1",
     "@types/express": "^4.16.0",
+    "@types/express-ws": "^3.0.0",
     "@types/get-port": "^4.0.0",
     "@types/jest": "^23.3.7",
     "del": "^3.0.0",

src/comms/WebSocketClient.ts

@@ -0,0 +1,34 @@
+import Client from './Client'
+import JsonRpcRequest from './JsonRpcRequest'
+
+/**
+ * A `Client` using the WebSockets API for communication.
+ */
+export default class WebSocketClient extends Client {
+
+
+  /**
+   * The URL of the `WebSocketServer` server
+   */
+  server: string
+
+  /**
+   * A [`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket) instance
+   */
+  socket: WebSocket
+
+  constructor (server: string) {
+    super()
+    this.server = server
+    this.socket = new WebSocket(server)
+    this.socket.addEventListener('message', (event: MessageEvent) => {
+      this.recieve(event.data)
+    })
+  }
+
+  // Overrides of `Client` methods
+
+  send (request: JsonRpcRequest) {
+    this.socket.send(JSON.stringify(request))
+  }
+}

src/comms/WebSocketServer.ts

@@ -0,0 +1,22 @@
+import expressWs from 'express-ws'
+
+import HttpServer from './HttpServer'
+
+/**
+ * A `Server` using WebSockets for communication.
+ */
+export default class WebSocketServer extends HttpServer {
+
+  constructor () {
+    super()
+
+    expressWs(this.app)
+
+    // @ts-ignore
+    this.app.ws('/', (ws, req) => {
+      ws.on('message', (request: string) => {
+        ws.send(this.recieve(request))
+      })
+    })
+  }
+}

tests/comms/browserTests.ts

@@ -1,7 +1,10 @@
 import HttpClient from '../../src/comms/HttpClient'
+import WebSocketClient from '../../src/comms/WebSocketClient'
 import WebWorkerClient from '../../src/comms/WebWorkerClient'
 
 var httpClient = new HttpClient('http://127.0.0.1:2000')
 
+var wsClient = new WebSocketClient('ws://127.0.0.1:2000')
+
 var worker = new Worker('webWorkerServer.js')
 var wwClient = new WebWorkerClient(worker)

tests/comms/webSocketServer.ts

@@ -0,0 +1,6 @@
+#!/usr/bin/env node
+
+import WebSocketServer from '../../src/comms/WebSocketServer'
+
+const server = new WebSocketServer()
+server.run()