找共同的朋友

Question

I'm working on an app using data from the facebook graph api. A user logs in and can generate stuff from his data on fb. We use, among other data, the number of mutual friends between the current user and each of his friends, using the me/mutualfriends/friend_id endpoint. The thing is, that's one request per friend. Even if we batch the requests, it is usually at least 4 not-so-quick requests.

So I'm wondering : we already have all the friends, and we only need the number of mutual friends, not any data about them (and anyway we already have it) : is there a better way, using less requests ?

Thanks for your time folks.

Answer 1

If you have every user's friends, then you can just take the intersection of two user's array of friends to get mutual friends.

user1_friends = ['a', 'b', 'c']
user2_friends = ['c', 'd', 'e']
mutual = user1_friends & user2_friends

mutual should be equal to ['c']

This should be far more efficient than reaching out to an endpoint.