In Facebook graph API how to find which all of your friends like a particular book or movie

Question

I'm trying to figure out how to find how many of my friends like a particular entity.

For example, for a given book or movie, how can I look up how many of my friends have already liked the same book or movie.

I believe that information does appear when we display the fb:like button social plugin but I want to get that count so I can programatically display the most popular books among my friends etc is descending order.

My backend is php but I'm also using Javascript SDK. Thanks for your inputs in advance

Answer 1

These "objects" are actually pages, so to retrieve your friends list that like a movie or a book (a page), use this query:

SELECT uid FROM page_fan WHERE page_id = 91290503700 AND uid IN (SELECT uid2 FROM friend WHERE uid1=me())

Try this in the console of fql.query, it will retrieve all your friends ID that likes the Inception movie.

EDIT:
The obvious way to retrieve the movies (for example) that your friends like would be:

SELECT page_id,uid 
FROM page_fan 
WHERE type="MOVIE" 
AND uid IN (
    SELECT uid2 
    FROM friend 
    WHERE uid1=me()
)

But I've noticed that it won't return all the users if the set is large (which most likely the case for every user)..so I've made a hack just to get you started!

function sectionArray($array, $step) {
    $sectioned = array();

    $k = 0;
    for ( $i=0;$i < count($array); $i++ ) {
        if ( !($i % $step) ) {
            $k++;
        }
        $sectioned[$k][] = $array[$i];
    }
    return $sectioned;
}

$result = $facebook->api(array(
    "method"    => "fql.query",
    "query"     => "SELECT page_id FROM page_fan WHERE type='MOVIE' AND uid IN (SELECT uid2 FROM friend WHERE uid1=me())"
));
$pages = array();

foreach($result as $k=>$v) {
    $pages[] = $v["page_id"];
}

$pages = array_unique($pages);
$pages = array_values($pages);
$sets = sectionArray($pages,10);

$movies = array();
foreach($sets as $set) {
    $page_set = implode(',',$set);
    $friends = $facebook->api(array(
        "method"    => "fql.query",
        "query"     => "SELECT page_id,uid FROM page_fan WHERE page_id IN ($page_set) AND uid IN (SELECT uid2 FROM friend WHERE uid1=me())"
    ));
    $movies[] = $friends;
}

$final = array();
foreach($movies as $v)
    foreach($v as $k=>$arr)
        $final[$arr["page_id"]][] = $arr["uid"];
print_r($final);

This code is doing the following:

1. Get all the MOVIEs ids that your friends like
2. Remove the repeated results and divide the resultant array to a set of arrays (10 movies each)
3. Query Facebook again to get the friends for each set (10 movies at a time) which would hopefully get you the full list of friends
4. sort by movie id

And the result would be something like:

Array
(
    [movie_id] => Array
        (
            [0] => friend_id
            [1] => friend_id
            [2] => friend_id
            [3] => friend_id
        )

    [movie_id] => Array
        (
            [0] => friend_id
            [1] => friend_id
            [2] => friend_id
            [3] => friend_id
            [4] => friend_id
            [5] => friend_id
            [6] => friend_id
            [7] => friend_id
        )

    [movie_id] => Array
        (
            [0] => friend_id
        )

    [movie_id] => Array
        (
            [0] => friend_id
        )
)

From here, you can check for the most liked...etc

P.S.: As I said the above just to get you started and I guess you can cache some queries and improve the performance.