get facebook user-id/username to fetch profile picture without Facebook SDK? PHP

Question

I'm looking for a way to get a users facebook profile id or username which i can use to get the profile picture based on the users account. I know how to fetch the picture already (http://graph.facebook.com/username_or_id/picture). I don't want to ask the user to submit their fb username (or worse - their profile id), i need it all done automatically (happy user).

Now i have not setup a Facebook app to use the facebook SDK so i don't have a appID or a secret code...

The reason for not setting it up is because im working on something that not only i will use. It's a project where others will be able to use on their own domain and i don't want to ask the users to setup their own FB app just to get this working so im looking for a way to do it, without the FB SDK? or have i got it all wrong?

Answer 1

You can do everything without FB SDK (it's just a library), but you can do nothing without application. So no, you can't get user's ID without their knowledge