Add remote.js to workshop template and pub/sub server

slides/autopilot/remote.js

@@ -0,0 +1,21 @@
+/* This snippet is loaded from the workshop HTML file.
+ * It sets up callbacks to synchronize the local slide
+ * number with the remote pub/sub server.
+ */
+
+var socket = io();
+var leader = true;
+
+slideshow.on('showSlide', function (slide) {
+  if (leader) {
+    var n = slide.getSlideIndex()+1;
+    socket.emit('slide change', n);
+  }
+});
+
+socket.on('slide change', function (n) {
+  leader = false;
+  slideshow.gotoSlide(n);
+  leader = true;
+});
+

slides/autopilot/server.js

@@ -19,7 +19,10 @@ app.get('/', function(req, res){
   res.send('container.training autopilot pub/sub server');
 });
 
-/* Serve slides etc. from the parent directory */
+/* Serve remote.js from the current directory */
+app.use(express.static('.'));
+
+/* Serve slides etc. from current and the parent directory */
 app.use(express.static('..'));
 
 io.on('connection', function(socket){

slides/workshop.html

@@ -31,5 +31,16 @@
         excludedClasses: [@@EXCLUDE@@]
       });
     </script>
+    
+    <!-- 
+    These two scripts will be available only when loading the
+    content using the pub/sub server. Otherwise, they'll just
+    404 and that's OK.
+    -->
+    <script src="/socket.io/socket.io.js">
+    </script>
+    <script src="/remote.js">
+    </script>
+
   </body>
 </html>