Facebook Connect with Extended Permission

When a Facebook user authorizes your application, your application gets access to the user’s Facebook ID. By default, your application can access all public data in a user’s profile, including her name, profile picture, gender, and friends. If your application needs to access other parts of the user’s profile that may be private, or if your application needs to publish content to Facebook on a user’s behalf, your application must request extended permissions.

For example if you want to get the email address of a particular facebook user, then you can use this extended permission option.

Facebooker gem is providing the option in the name ‘permsToRequestOnConnect’ like below:

<%= init_fb_connect "XFBML", { :app_settings => " { permsToRequestOnConnect : 'email' }"} %>
So after adding this, When you click on Connect button it will pop-up the Facebook authorization form with email access request like below:

For more extended permission option refer to this link.