2012-03-17

Camel now with twitter and websocket

The upcoming Apache Camel 2.10 is well underway. A lot of new components is being added, and two really exiting new components is twitter and websocket. Its yet another kick ass contributions from the community that makes this possible.

James Strachan and I gave a talk last month at the JFokus conference in Stockholm. And for that conference I had prepared a little example using these new components. Unfortunately there was a problem with the projector and James laptop, so we had to give the presentation with slides only.

So this weekend I found some time again, to polish the example, prepare documentation, and donate the example to the Apache Camel project.

The example is demonstrating how to poll a constant feed of twitter searches and publish results in real time using web socket to a web page. As usual the code in Camel is very simple. All it takes is roughly

  from("twitter://search?...")
    .setHeader("websocket.sendToAll", "true")
    .to("websocket:camel-tweet")

To use twitter, you need a twitter account which have setup an application to be used. For twitter users, you may be familiar that twitter requires you to grant applications access to your twitter account, such as twitter for iphone etc. The same applies for this example.

We have described this in more details at the Camel twitter documentation.

When you have created an application, you get a number of details back from twitter which you need to use the twitter component. We will get back to this later.

This example is located in the examples directory of Apache Camel 2.10, in the camel-example-twitter-websocket. To run the example you use Maven with the following command: mvn compile exec:java

The example will report error if you have not setup your twitter application. To do that edit the source code in the src/main/java/org/apache/camel/example/websocket/CamelTwitterWebSocketMain.java class.

When successfully setup the applications starts, and you can open a web browser on page http://localhost:9090/

By default we do a twitter search every 2nd second for the word "gaga". There is usually a lot of people tweeting about Lady gaga :). You can of course change this in the aforementioned source file.

Below is a screenshot of the example in action.
Live feeds of gaga tweets using Camel in a web browser
The client is a web browser, so we need to setup this in a .html page using JavaScript. See the src/main/resources/index.html for the source code.

The interesting piece in the source code is that its very easy to setup a websocket client
  var location = "ws://localhost:9090/camel-tweet";

  this._ws=new WebSocket(location);
  this._ws.onmessage=this._onmessage;
  this._ws.onclose=this._onclose;

Notice that all it requires is an url to pass into the WebSocket constructor. And then setup two functions for callbacks.

Have fun, and I tried using Metallica as the search term, but I must admit that there are more frequent tweets about Gaga. 
Metallica tweets
Anyone its time to end this blog, and get the code committed. And to enjoy some Metallica music, and have a nice weekend.



4 comments:

Bruno Borges said...

I am very happy to see that a code I started years ago ended up on Camel's trunk and is now part of Camel 2.10 :-)

Thanks Claus for sharing this with all of us!

May I use your example to a talk I'm going to give in a few weeks?

Cheers!

Claus Ibsen said...

Hi Bruno

Thanks for the contribution to Camel.

And yes you may very well use the example for your talk. The example is now part of the Camel examples, out of the box: http://camel.apache.org/twitter-websocket-example.html

Jason Separovic said...

Hi,
I was wondering whether you guys are considering to add support for the twitter user stream endpoint. It looks like the camel-twitter component currently only supports the public stream endpoint.
Tweets from protected accounts can only be received on the user and site stream endpoints.
Cheers

Claus Ibsen said...

Jason

You can see which tickets we have about camel-twitter in JIRA at: https://issues.apache.org/jira/browse/CAMEL/component/12317101

We love contributions, so people is very much welcome to develop and contribute such functionality.

You are also welcome to create a JIRA ticket about this, this is a way for the community to say we would like X functionality added to Camel.

You can read about contributing to the project here: http://camel.apache.org/contributing.html