How to Build a Facebook-like Platform on Google App Engine?

I am interested to build a platform on Google App Engine where one Master App provides common functionality to several child Apps (Web portals).

Master App:

• Offers Common Social Networking features
开发者_如何转开发
• Common user database
• Interacts using Web services API

Child Apps (Web Portals):

• Connects to Master App for user database and social networking features
• Uses Local business logic for local features

My Design plan is:

1. Master and Child Apps will be individual Apps on GAE Appspot (for easy management)
2. All will communicate via REST/JSON?
3. I will enable billing for all Apps so nothing is against Google's usage policy.
4. Will use SSL for login into Master App, later use a token (cookie) for further interactions

Could anyone kindly spot risks and suggest any improvements?

Your "Master/Child" concept will be hard to maintain, introduce issues with cross-site-scripting and most importantly be completely against Google App Engine's terms of service for combining multiple apps into one.

4.4. You may not develop multiple Applications to simulate or act as a single Application or otherwise access the Service in a manner intended to avoid incurring fees.

You could use multiple app versions (defined on app.yaml) to deploy different codebases to the same appspot.com subdomain, and access them like http://app1.myapp.appspot.com, http://app2.myapp.appspot.com for "versions" app1 and app2. You could even have one version running on Java and another one on Python. They'll all share the same datastore, although you'd be able to use namespaces to separate them if necessary.

For the distributed nature of the architecture you proposed, I'd suggest having a deep look at Facebook's graph API and Twitter's API. They both use oAuth for authentication/authorization and already have a proven implementation of what you're trying to accomplish.