Login system just like stackoverflow's, written in php

Question

The question Is there a simple way to implement the login system that stackoverflow uses using php?

For a long time I have developed websites, and have used a typical web form username/password with a mysql db for login systems.

I would like to have it so users can log into the system using google, yahoo, facebook, etc, and without them having to remember some long openid url (they should just click google and be able to log in using their username/password there).

I would prefer not to use a service provider (such as RPX) to implement this.

Answer 1

If you want to implement it yourself, here is a great walkthrough. There's also the PHP OpenID Library, but that's probably a lot more than you need.

Here is the client-side OpenID selector that SO uses on its login screen.

Edit: Stack Overflow no longer uses the one that I linked to, but it still works, as far as I'm aware.

Answer 2

Check which pages clicking those buttons sends you to and then just redirect your users to those pages. They are all "openid" providers so you just need an open id library on your end to verify the response.

I use this one in PHP http://openidenabled.com/php-openid/. They have some good examples in that package to get you started.

Answer 3

If you're looking at using preexisting code, the Zend Framework provides OpenID support. While the library itself is fairly large, you should be able to individual components in a relatively stand-alone way.