I haven't been able to do so due to all sort of missing dependencies (mainly, I think the problem is in the authentication code which relies on django stuff that is not available on AppEngine)
I was wondering if anyone patched\forked piston to get it working on AppEngine?
It turns out the problem with Piston and AppEngine is mainly when it comes to the authentication code. So, I managed to port Piston to AppEngine doing the following: