php preg_match help getting facebook username/id from URL

Question

I am trying to get the facebook username or id from a facebook url and was wondering if you could help me. I'm sure it's just a simple regex function but I have tried and can't seem to do it myself.

Here's what I've been trying to get from the url.

http://www.facebook.com/myusername/

or the numerical id

http://www.facebook.com/2285652/

I would be very grateful if anyone could help me achieve this via PHP

Answer 1

preg_match('#https?\://(?:www\.)?facebook\.com/(\d+|[A-Za-z0-9\.]+)/?#',$str,$matches);

The pattern is versatile so it matches:

1. http and https URL's.
2. URL's with or without the www prefix.
3. URL's with or without the trailing /.
4. Matches Facebook numerical ID's.
5. Matches Facebook's rules for usernames.

Usernames can only contain alphanumeric characters (A-Z, 0-9) or a period (".").