In my application I want users to be able to challenge other users, and since facebook has take away my ability to issue notifications, I would like to be able to send either invites or emails.
If the user already is playing the game, I'll send them an email. If they are not, I want to send them an invite from the challenging player. However this is all the documentation facebook gives me: http://developers.facebook.com/docs/guides/canvas/#requests and it doesn't tell me how to programmatically send invites.
How can I send invites to a user from a user without having the user go to the invite page?