Question

Within a facebook app, is there a reliable way ensure, that a given action can only be performed once per facebook user, without asking the user to authorize the app?

From the looks of the documentation and the lack of positive responses to this question I would deduce it’s impossible, but I have been told the adverse – without actual details.

So what I need to know:

• Is there any way to achieve this?

  or (if not):

• Is there any resource that clearly states that this is impossible?

Answer 1

Can you give a more detailed example of what you are trying to do and which language you are trying to do it in?

If you have the ability to access the user_id through an indexable field like you have in a friend, like or event relationship, you could just store the user_ids in your own database as they take actions in your page. If they’ve already performed the action once, you’d just give a message to the user and drop whatever action just occurred. You can find all the indexable fields in the fql documentation.

If you want to get the id from a random user who happens across your app, they need to authorize your app before you can get access to their information.

I’ve seen a few scam apps on FB that manage to get user permissions as soon as a logged in user visits their page. These violate the TOS and most likely get deleted and their admin banned as soon as they are reported.