Facebook: how to persist sessions in a (connect/graph) application

I am using the facebook graph api to integrate some 开发者_如何学Cfacebook functionality for users into a project i am working on. Its very early stages and I am just getting to grips with the Facebook API but it appears that every time a user logs on to my site they will also have to log into Facebook. On the first time they also have to authenticate my application.

I am a little surprised that they have to actually log into Facebook each time they want to use any Facebook features from inside my app.

Isn't there a way to authenticate once, then I can store a token and this would allow me to access Facebook on their behalf in the future (until they de-authorize) without them having to log into Facebook each and every time?

This just seems very cumbersome.

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Request the user for offline_access permissions using the scope argument in the authorization request
http://developers.facebook.com/docs/authentication/#requesting-extended-permissions
You can use the session key returned, save it and use it until it expires (this usually is very long) or until the user revokes access to your application

Here is the full list of extended permissions your application can ask for http://developers.facebook.com/docs/authentication/permissions