Facebook Connect on multiple domains with centralized login

we are looking into implementing Facebook Connect on our wiki service, http://www.wikidot.com. User-created sites span the *.wikidot.com domain, but also custom domains (like mine http://michalf.me), all handled by our single service.

We have a centralized account system. Users always log in (and create accounts) at www.wikidot.com and they are automatically logged in in all subdomains (cookie domain set to .wikidot.com - easy) and custom domains (automatically, via a series of redirects).

We would like to add FC into our login flow. Now, it would be great to get some clarification about FC Terms, which suggests using one App ID for every domain. In our case however user-created sites are not separate applications.

So, is it OK to use FC on one centralized website where our users log in (on www.wikidot.com) and expand user status on other domains connected to our service? This is 开发者_开发问答how it works right now, without FC.

It would be great if we could get clarification from someone from FB to make sure we will not be violating any terms or policies.

Thanks!

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It isn't possible (as far as I know anyway) to use the same app ID on multiple domains. FB allows use across subdomains, but I have found some difficultly with this even at times with the cookies. When you set up an app, you are asked to provide the domain for it. The domain you put here is the only domain that your app will work for. If your users are only ever signing in on wikidot.com, then I suppose you can use what you have already to move those sessions onto the other domains, but once you are on the other domain, you won't be able to use any of the facebook api features; any requests you make will fail.

I think the 'one app id for every domain' condition is more to target people who are trying to use multiple app ids for one domain. I think so long as you aren't transferring any data about the user to different domains/adverts etc, you should be ok. Essentially what you are doing is adding FB connect to your wikidot site, then a separate feature of wikidot is to keep you logged in on other partner sites?