I am working on a project that involves mobile and web clients with Google's AppEngine PAAS. I would like to use RESTFul webservices with my AppEngine app.
I have looked over Stackoverflow for references to RESTFul service frameworks that can be used with AppEngine for both web (GWT) and mobile (Android) clients. Although Restlet
seems to provide editions for AppEngine, GWT and Android, so far I've got it down to RestEasy
mostly due to this question.
There have been questions previously that discuss RESTFul frameworks but I don't think the comparisons apply well to this, now quite common, case. It would be helpful to hear experienced developers' views on the frameworks available for this set of platforms and merits versus demerits of each.
I've been using spring restful services with lots of luck on GAE and have been consuming it with Android Native, Phonegap and IOS clients with no issues whatsoever.
http://blog.springsource.org/2009/03/08/rest-in-spring-3-mvc/
You might wish to consider using Google Cloud Endpoints, which was announced as a trusted tester feature for App Engine at Google I/O, and is now available to everyone. With Endpoints, you annotate simple Java (or Python) classes and methods to describe your API. For example, this is a simple class to get and retrieve a list of high scores from a Tic Tac Toe game:
Features
Learn More
Check out the documentation for more details on using Endpoints.
You can also watch several talks from Google I/O:
I would also like to recommend Restlet, see also other threads here
Restlet has an edition for GAE, see http://wiki.restlet.org/docs_2.0/13-restlet/275-restlet/252-restlet.html
But there are also other libraries which come with special editions for GAE, for example: http://code.google.com/p/xydra/wiki/RestLess
If you are looking at GAE, one choice you may consider is duyproject. It is know for it's openid library, but it also has a very light weight library for REST servlets. And with GAE you want to keep all the libraries light so you don't go over the byte limit.
I respect your decision not to use Restlet, but for other browsers of this thread, I have been able to make Post work with Android/Restlet/GAE - and my knowledge and programming skills are fairly limited. I had some problems getting the Restlet Edition for Javascript to work correctly (it is still in early development), but Restlet for Android posed no problems that I can recall.