Using Cookies for authenticated users

Can anyone tell me of good tutorials that will explain how to ge开发者_运维技巧nerate a cookie for when a user logs into my system through Foursquare, so I can keep track of their information? Or is there any other methods which I should look at?

To store semi-sensitive data, you should use a session variables. Sessions are stored on the server, with a unique cookie sent to each unique client. This way, you have control over what's in the session variable, but the user can still be uniquely identified. For info on sessions in app engine, see this post.