GWT on Python App Engine

Question

I have a python app engine code (matured backend) - and we are now planning to have a front end for that code.

I was wondering whether it is possible to implement GWT as the front end.

Even though Alex Martelli in this post [1] mentions it is not possible, a comment to that post suggests that it is indeed possible using rpc over json for GWT.

I was unable to understand how this is possible. In app.yaml file, we have to specify the language to be python, right? In that case, how can it compile GWT based on JAVA? Are there any examples on anyone doing that?

Can someone help me out? It would be extremely helpful.

[1]: Choosing Java vs Python on Google App Engine link

Answer 1

I use GWT with Python quite a bit - the JSON interface works perfectly well. Your GWT front-end is still written in a java-like syntax, and you still need the Java toolchain to actually compile it down to HTML/Javascript, but it doesn't care what language the backend is written in.

As for how this is accomplished - the GWT toolchain is completely independent of GAE, there's no executable Java on the AppEngine side. You design and write your frontend in GWT on your own system, and then compile it to HTML/JS, which is what you upload to GAE.