Cloned DMOJ

resources/event.js

@@ -0,0 +1,68 @@
+function EventReceiver(websocket, poller, channels, last_msg, onmessage) {
+    this.websocket_path = websocket;
+    this.channels = channels;
+    this.last_msg = last_msg;
+    this.poller_base = poller;
+    this.poller_path = poller + channels.join('|');
+    if (onmessage)
+        this.onmessage = onmessage;
+    var receiver = this;
+
+    function init_poll() {
+        function long_poll() {
+            $.ajax({
+                url: receiver.poller_path,
+                data: {last: receiver.last_msg},
+                success: function (data, status, jqXHR) {
+                    receiver.onmessage(data.message);
+                    receiver.last_msg = data.id;
+                    long_poll();
+                },
+                error: function (jqXHR, status, error) {
+                    if (jqXHR.status == 504)
+                        long_poll();
+                    else {
+                        console.log('Long poll failure: ' + status);
+                        console.log(jqXHR);
+                        setTimeout(long_poll, 2000);
+                    }
+                },
+                dataType: "json"
+            });
+        }
+        long_poll();
+    }
+
+    this.onwsclose = null;
+    if (window.WebSocket) {
+        this.websocket = new WebSocket(websocket);
+        var timeout = setTimeout(function () {
+            receiver.websocket.close();
+            receiver.websocket = null;
+            init_poll();
+        }, 2000);
+        this.websocket.onopen = function (event) {
+            clearTimeout(timeout);
+            this.send(JSON.stringify({
+                command: 'start-msg',
+                start: last_msg
+            }));
+            this.send(JSON.stringify({
+                command: 'set-filter',
+                filter: channels
+            }));
+        };
+        this.websocket.onmessage = function (event) {
+            var data = JSON.parse(event.data);
+            receiver.onmessage(data.message);
+            receiver.last_msg = data.id;
+        };
+        this.websocket.onclose = function (event) {
+            if (event.code != 1000 && receiver.onwsclose !== null)
+                receiver.onwsclose(event);
+        }
+    } else {
+        this.websocket = null;
+        init_poll();
+    }
+}