Different theme for different urls with the same google app engine instance?

I am considering developing a platform in GAE.

for this to work I would like to be able to have run the same app engine 开发者_开发问答instance run several 'sister' sites. This would be something similar to the way that the stack exchange sites work, so each 'sister' site would have its own users, data and theme (but may potentially be configured slightly differently - think different plugins used), but essentially would have the same function & format.

I would like to know if it would be possible to have each sister site have its own (customer defined) url, which would use the same app engine instance, and the app engine instance would be configured (by setting the site id and valid plugins for that site) depending on the url which was used to access it.

Yes, this is entirely possible. As Fox32 points out, you can use namespaces to separate different datasets. For domains, App Engine supports wildcard mappings, so you can map *.yoursite.com to your app. If you want to add custom TLDs, either you or your customers will need to create a Google Apps account for them, or add the domain as an alias on an existing Apps account, and associate it with the App Engine app - this doesn't require that they be admins of your app to do so.

You can use namespaces, to separate different websites, for many api methods. Take a look at the GAE documentation about it.

The Namespaces API is integrated with Google Apps, allowing you to use your Google Apps domain as the current namespace. Because Google Apps lets you deploy your app to any domain that you own, you can easily set unique namespaces for all domains linked to your Google Apps account.