Chidambaram's Blog

Srikanth,
You mentioned the following 2 things in your review of MapYourBuddies. While I can't speak for that group, here is my insights on why this might be the case. Here are the 2 comments you made.

1. Once login if i refresh the page,it doesnot loads the page.i.e refresh doesnot work

The login process in MYB creates a session in facebook (after you type in the password) and returns a token, which inturn is used to retrieve the session key. While a session key can be used for subsequent requests (within the same session), the token can be used only once. This is one of the general concept in a web application. When a page is refreshed using F5 or refresh button, we are re-submiting the same information to the server again. If you notice the URL parameter (in MYB), the token is being submitted to the PHP again and it gives a invalid parameter message

http://people.emich.edu/jwendelk/MapYourBuddies/I2/main.php?auth_token=b55f3cd7671d5220a75c4645a93c5b4b

If you remove the auth_token parameter and hit enter, you'll be getting the main page again and then you can choose Start MayYourBuddies button ....it'll not ask you for login credentials again (because the session still exists) ....which is the expected behaviour. Hope this helps.

MYB team ....You can prevent this error by checking for the auth_token parameter in the incoming request (in your php) and either redirect the user to your home page automatically or pull values from facebook using the session key previously created (skip the login stuff) ...Just a thought.

2. Once i exit from my login still it continues to be on my login if i press back option

When you use back button, browsers are not always required to send the previous request back to the server (some browsers differ though). In this case, I suspect, the page you are seeing is coming from your browser cache. MYB team, I am not sure whether you are invalidating the session when the user logs out.... Its always a good idea to use session_destroy() in your php when user logs out. This will clear the session and also free-up your server memory !!

Sorry if I am stepping on your turf !!! And Sorry for the long post folks !!! :-))