Reconnect websockets automatically

package.json

@@ -5,7 +5,8 @@
   "scripts": {
     "ng": "ng",
     "start": "ng serve --proxy-config proxy.conf.json",
-    "build": "ng build --prod --aot --build-optimizer"
+    "build": "ng build --prod --aot --build-optimizer",
+    "lint": "ng lint --fix"
   },
   "private": true,
   "dependencies": {

src/app/services/terminado.service.ts

@@ -8,11 +8,16 @@ export class TerminadoService {
   xterm: Terminal;
   ws: WebSocket;
   attached = false;
+  private dataListener: any;
+  private resizeListener: any;
 
   constructor() {
     Terminal.applyAddon(fit);
-    Terminal.applyAddon(terminado);
-    this.xterm = new Terminal({
+    this.xterm = this.createTerminal();
+  }
+
+  createTerminal() {
+    return new Terminal({
       theme: {
         foreground: '#ffffff',
         background: '#0C0C0C',                  // $tao-gray-800
@@ -37,26 +42,52 @@ export class TerminadoService {
       },
       fontSize: 14
     });
-
-    const wsproto = (location.protocol === 'https:') ? 'wss://' : 'ws://';
-    this.ws = new WebSocket(wsproto + window.location.host + '/terminal');
   }
 
   attach(element: HTMLElement) {
+    if (this.attached) {
+      return;
+    }
+
+    const wsproto = (location.protocol === 'https:') ? 'wss://' : 'ws://';
+    this.ws = new WebSocket(wsproto + window.location.host + '/terminal');
+
     this.ws.onopen = () => {
-      (<any>this.xterm).terminadoAttach(this.ws);
+      this.attached = true;
+      this.xterm = this.createTerminal();
       this.xterm.open(element);
       this.fit();
-      this.xterm.blur();
-      this.attached = true;
+      // In order to reset the terminal state after a broken socket, we need to register the listeners manually.
+      (<any>this.xterm)._core.register(this.dataListener = this.xterm.onData(data => {
+        this.ws.send(JSON.stringify(['stdin', data]));
+      }));
+      (<any>this.xterm)._core.register(this.resizeListener = this.xterm.onResize((size: { rows: number, cols: number }) => {
+        this.ws.send(JSON.stringify(['set_size', size.rows, size.cols]));
+      }));
+    };
+
+    this.ws.onclose = () => {
+      this.detach();
+      this.xterm.destroy();
+      this.attach(element);
+    };
+
+    this.ws.onmessage = msg => {
+      const data = JSON.parse(msg.data);
+      if (data[0] === 'stdout') {
+        this.xterm.write(data[1]);
+      }
     };
   }
 
   detach() {
-    (<any>this.xterm).terminadoDetach(this.ws);
-    this.xterm.destroy();
-    this.ws.close();
+    if (!this.attached) {
+      return;
+    }
+
     this.attached = false;
+    this.dataListener.dispose();
+    this.resizeListener.dispose();
   }
 
   fit() {

src/app/services/websocket.service.ts

@@ -1,5 +1,5 @@
 import { Injectable } from '@angular/core';
-import { Observable } from 'rxjs';
+import { Observable, Subject, Subscription } from 'rxjs';
 import { webSocket, WebSocketSubject } from 'rxjs/webSocket';
 import { filter, map } from 'rxjs/operators';
 import { WebSocketMessage } from '../message-types/websocket-message';
@@ -17,14 +17,28 @@ export enum Intent {
 @Injectable()
 export class WebSocketService {
   private ws: WebSocketSubject<WebSocketMessage>;
+  private subject: Subject<WebSocketMessage> = new Subject<WebSocketMessage>();
+  private subscription: Subscription;
 
   constructor() {}
 
   public connect() {
     if (!this.ws) {
+      if (this.subscription) {
+        this.subscription.unsubscribe();
+      }
       const wsproto = (location.protocol === 'https:') ? 'wss://' : 'ws://';
       const connAddr = wsproto + window.location.host + '/ws';
-      this.ws = webSocket<WebSocketMessage>(connAddr);
+      this.ws = webSocket<WebSocketMessage>({
+        url: connAddr,
+        closeObserver: {
+            next: closeEvent => {
+                this.ws = null;
+                this.connect();
+            }
+          }
+      });
+      this.subscription = this.ws.subscribe(msg => this.subject.next(msg));
     }
   }
 
@@ -35,7 +49,7 @@ export class WebSocketService {
   }
 
   public observeAll<T extends WebSocketMessage>(key: string): Observable<T> {
-    return this.ws.pipe(
+    return this.subject.pipe(
       filter(message => message.key.startsWith(key)),
       map(message => <T> message)
     );