getting logged-in user's details on another user's facebook profile tab

I have a Facebook application that has a user profile tab. The specs of the app dictate that the layout of the profile tab should be different depending on whether a user is looking at their own profile, or someone else is 开发者_StackOverflow社区looking.

Whenever I try to print_r FB's signed request details, the profile_id is always the same as the user_id, even if I am looking at the profile as another user.

Is there another way I can get this information, or is it not possible using Facebook's current setup?

Thanks!

Facebook sends visitor id only after they interact with your tab in some way, but not during the first visit.

In theory the Canvas signed_request functionality is meant to solve this issue too, but I'm having the same issue around the user needing to interact with the tab first.

Personally, I think that's stupid with respect to signed_request functionality, as it looks like I need to request permissions I don't need in order to get it to do what I thought the purpose of the functionality change was (see #3362040 for an example).

Griping aside, though, you might find the signed_request functionality helpful for this.