Wednesday, December 09, 2009

Cloud + OSGi + GWT + ECF Rest + Twitter API = Modular web services

Using several technologies, I've recently created a Twitter user status service...i.e. a web service that retrieves the latest user status for a given user.

Click here to use/try it

You will need a Twitter username and password to get that user's status.

Here's what was used

Web Server: EclipseRT, p2, Equinox servletbridge
Ajax Web UI: Google Web Toolkit (GWT)
REST API: ECF REST/remote services API, Twitter REST API/service
Cloud provider: Amazon Cloud/Web Services (AWS)

The use of OSGi modularity makes this not only possible, but this server/service consists only of the bundles necessary to actually provide this service...and each of those used are small.


Matt Raible said...

Here's a version that does the same thing with OAuth (vs. HTTP Basic Authentication) and a ProxyServlet to get around SOP.

Scott Lewis said...

Hi Matt,

Thanks...the OAuth via GWT looks very interesting.

Is yours an OSGi web server as well?

And what is the acronym SOP? I don't recognize it in this context. Thanks.

Scott Lewis said...

Hi Matt...I accidently hit the reject link and rejected this posting by apologies to Matt as I had intended to accept it:

No, it's not an OSGi web server, just a WAR on Tomcat. OSGi seemed like overkill for this type of application. ;-)

SOP = Single Origin Policy.

Scott Lewis said...

Hi response to your statement:

"OSGi seemed like overkill for this type of application. ;-)"

After creating this service, I would strongly disagree that OSGi is OSGi (and modularity more generally) allowed/allows the server/service to be lightweight/simple...with very small application-level code. For example, excluding the GWT UI, the *total* code size for the application is < 50k.

Chris Brind said...

You'd be amazed how people think OSGi (and 'modularity' in general) is overkill for such a small project. I have to content with this kind of thing in my organisation.

But I've just categorically proved after an intense 3 week project (read non-disposable prototype) using OSGi and Flex that OSGi (and modularity) from day 1 has not only given us a solid platform up on which to build, but actually made the whole development process a lot faster.

I'll be writing a report on this in my blog next week - our final delivery day is tomorrow and we're well on track. ;-)


Scott Lewis said...

Hi Chris.

Great to hear you are having good success. Please do give a report on your blog about your experiences...positive and negative. Only by communicating will improvements result...

Scott Lewis said...

@Chris (and others). You might like Martin Lippert's most recent set of slides on osgi/architecture/modularity.

Martin Lippert's blog

Anonymous said...

Your blog is very informative and very helpful. Thanks for this.
Web development

Scott Lewis said...


Thanks for the nice words. If you find what I'm doing interesting WRT your project and/or what your organization is doing, please do let me know and perhaps I can help create some value for you/yours as well. I can be reached at slewis at

And Happy New Year.

Anonymous said...

Your blog keeps getting better and better! Your older articles are not as good as newer ones you have a lot more creativity and originality now keep it up!

Unknown said...

Your blog is really cool! I will wait when you finish. Thank you for interesting articles.
more templates easy to download

Scott Lewis said...

I mistakenly rejected a valid comment by Nawa:

I can see sources somewhere?

Scott's answer is: currently no...the sources are not available publicly. That's primarily because I haven't had any resources to make them available (time and CVS server).

Hendy said...

Please publish sources on :)

Scott Lewis said...

Hi Hendy.

Most of the pieces for this (OSGi/HttpService, GWT, ECF, etc.) are already available in open locations:


If you wish to help me with this project, and expedite making things available in a more central form, please contact me at slewis at