Facebook Graph API: Check if user has liked a specific post - facebook

Question

I am rather new to Facebook Graph API and I'm trying to find out if a user has liked a specific post.
Right now, in order to achieve this, I get all the likes for that post and then I iterate through them to find a match. But this procedure requires a lot of requests when the number of likes is too high, as the maximum number of likes per request appears to be 100.
Is there any better way to check if the user has liked the post?

Answer 1

Request the summary of the likes (post_id?fields=likes.limit(0).summary(1)), then you will get a data structure that looks like this:
{
"likes": {
"data": [
],
"summary": {
"total_count": 1,
"can_like": true,
"has_liked": false
}
},
"id": "…"
}
The properties can_like and has_liked reflect the values for the user who’s access token you used to make the request.
UPDATE
The latest version of Graph API today is v2.8. In this version you can get the reactions also. It is better to use reactions than likes as reactions also includes the Love, WOW and HAHA etc reactions which likes does not.
You can add the field for reactions's summary instead of likes's summary as below
fields=reactions.limit(0).summary(true)
Using this you will get the reactions summary as below
"reactions": {
"data": [
],
"summary": {
"total_count": 6,
"viewer_reaction": "LOVE"
}
}, ......
Notice the "viewer_reaction": "LOVE" which means you have given a reaction to the post which is LOVE. It's value could be any one of LIKE, LOVE, HAHA, WOW, SAD, ANGRY, NONE. The NONE means you have not liked the post.