Adding server-sent events

Author: mattpodwysocki

Gruntfile.js

@@ -32,6 +32,7 @@ module.exports = function (grunt) {
             'src/jsonp.js',
             'src/websocket.js',
             'src/webworker.js',
+            'src/evensource.js',
             'src/mutationobserver.js',
             'src/requestanimationframescheduler.js',
             'src/mutationobserverscheduler.js',
@@ -52,6 +53,7 @@ module.exports = function (grunt) {
             'src/jsonp.js',
             'src/websocket.js',
             'src/webworker.js',
+            'src/evensource.js',
             'src/mutationobserver.js',
             'src/requestanimationframescheduler.js',
             'src/mutationobserverscheduler.js',

bower.json

@@ -1,6 +1,6 @@
 {
   "name": "rxjs-dom",
-  "version": "4.0.0",
+  "version": "4.0.1",
   "main": "dist/rx.dom.js",
   "dependencies": {
     "rxjs": "*"

doc/operators/fromeventsource.md

@@ -0,0 +1,59 @@
+### `Rx.DOM.from(url, [openObserver])`
+[Ⓢ](https://github.com/Reactive-Extensions/RxJS-DOM/blob/master/src/eventsource.js "View in source") 
+
+This method wraps an EventSource as an observable sequence which is used to send server-side events.  Note that your browser must support EventSource objects.
+
+#### Arguments
+1. `url` *(String)*: The URL of the Server-Side Events.
+3. `[openObserver]` *(`Rx.Observer`)*: An optional Observer to capture the open event.
+
+#### Returns
+*(`Observable`)*: An observable sequence which represents the data from a server-side event.
+
+#### Example
+```js
+// Using a function for the open
+var source = Rx.DOM.fromEventSource('foo.php');
+
+source.subscribe(function (e) {
+  console.log('Received data: ' + e.data);
+});
+
+
+// Using an observer for the open
+var observer = Rx.Observer.create(function (e) {
+  console.log('Opening');
+});
+
+// Using a function for the open
+var source = Rx.DOM.fromEventSource('foo.php', observer);
+
+socket.subscribe(function (e) {
+  console.log('Received data: ' + e.data);
+});
+
+socket.onNext('data');
+```
+
+### Location
+
+File:
+- [`/src/eventsource.js`](https://github.com/Reactive-Extensions/RxJS-DOM/blob/master/src/eventsource.js)
+
+Dist:
+- [`rx.dom.js`](https://github.com/Reactive-Extensions/RxJS-DOM/blob/master/dist/rx.dom.js) | - [`rx.dom.compat.js`](https://github.com/Reactive-Extensions/RxJS-DOM/blob/master/dist/rx.dom.compat.js)
+
+Prerequisites:
+- If using `rx.js`
+  - [`rx.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.js) | [`rx.compat.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.compat.js)
+  - [`rx.binding.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.binding.js)
+- [`rx.lite.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/rx.lite.js) | [`rx.lite.compat.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/rx.lite.compat.js)
+
+NPM Packages:
+- [`rx-dom`](https://preview.npmjs.com/package/rx-dom)
+
+NuGet Packages:
+- [`RxJS-Bridges-HTML`](http://www.nuget.org/packages/RxJS-Bridges-HTML/)
+
+Unit Tests:
+- [`/tests/tests.eventsource.js](https://github.com/Reactive-Extensions/RxJS-DOM/blob/master/tests/tests.eventsource.js)

doc/readme.md

@@ -64,6 +64,9 @@ This section contains the reference documentation for the Reactive Extensions fo
 - [`Rx.DOM.post`](operators/post.md)
 - [`Rx.DOM.jsonpRequest`](operators/jsonprequest.md)
 
+Server-Sent Events
+- [`Rx.DOM.fromEventSource`](operators/fromeventsource.md)
+
 Web Sockets
 
 - [`Rx.DOM.fromWebSocket`](operators/fromwebsocket.md)

package.json

@@ -2,7 +2,7 @@
   "name": "rx-dom",
   "title": "The Reactive Extensions Bindings for the DOM.",
   "description": "Library for using DOM elements as well as Ajax requests",
-  "version": "4.0.0",
+  "version": "4.0.1",
   "homepage": "https://github.com/Reactive-Extensions/RxJS-DOM",
   "author": {
     "name": "MS Open Tech",

src/eventsource.js

@@ -0,0 +1,42 @@
+  if (!!root.EventSource) {
+
+    /**
+     * This method wraps an EventSource as an observable sequence.
+     * @param {String} url The url of the server-side script.
+     * @param {Observer} [openObserver] An optional observer for the 'open' event for the server side event.
+     * @returns {Observable} An observable sequence which represents the data from a server-side event.
+     */
+    dom.fromEventSource = function (url, openObserver) {
+      return new AnonymousObservable(function (observer) {
+        var source = new root.EventSource(url);
+
+        function onOpen(e) {
+          openObserver.onNext(e);
+          openObserver.onCompleted();
+          source.removeEventListener('open', onOpen, false);
+        }
+
+        function onError(e) {
+          if (e.readyState === EventSource.CLOSED) {
+            observer.onCompleted();
+          } else {
+            observer.onError(e);
+          }
+        }
+
+        function onMessage(e) {
+          observer.onNext(e);
+        }
+
+        openObserver && source.addEventListener('open', onOpen, false);
+        source.addEventListener('error', onError, false);
+        source.addEventListener('message', onMessage, false);
+
+        return function () {
+          source.removeEventListener('error', onError, false);
+          source.removeEventListener('message', onMessage, false);
+          source.close();
+        };
+      });
+    };
+  }