Can I know which user made an invitation once it is accepted?

I'm creating Facebook app. I need to know if i can count the number of invitations a person has made (invitations to his/her friends to use the app). I also need to know how many of these invitations have been accepted (not rejected or ignored). Can I count the invitations? Is there a way to know who made the invitation when a user is a开发者_如何转开发ccepting or rejecting one?

We are working with the PHP API for facebook.

Yes, but you'll need to do some work on your end to track these things. Take a look at https://developers.facebook.com/docs/reference/dialogs/requests/ to see how the requests dialog works. Ideally you'll log the request ids then loop through the request ids to pull out the information into your database to track which requests were successful.