How to make big Facebook API requests faster? - php

Question

I am working on an Facebook application in PHP that fetches a large amount of location information of the user's friends. The application gets increasingly slow as the number of friends of the users increases. But the more friends' information I retrieve, the more accurate is the result.
I have tried to use the following ways to speed up the query:
$facebook->api('/locations?ids=uid1,uid2,uid3,...')
And I used this together with batched requests:
$batched_request = array(
array('method' => 'GET', 'relative_url' => '/locations?ids=uid1,uid2,uid3,...'),
array('method' => 'GET', 'relative_url' => '/locations?ids=uid11,uid12,uid13,...'),
array('method' => 'GET', 'relative_url' => '/locations?ids=uid21,uid22,uid23,...'),
...
);
$batch = $facebook->api('/?batch='.json_encode($batched_request), 'POST');
But still it takes at least 20 seconds to get the location information from a random set of 100 friends of the user.
Actual Code Used
This part is fine. It gets done in just a few seconds.
$number_of_friends = "100"; // Set the maximum number of friends from which their location information is retrieved
$number_of_friends_per_request = 10; // Set the number of friends per request in the batch
$access_token = $facebook->getAccessToken();
// This is the excerpt of another batched request to get the friend ids
$request = '[{"method":"POST","relative_url":"method/fql.query?query=SELECT+uid,+name+FROM+user+WHERE+uid+IN(SELECT+uid2+FROM+friend+WHERE+uid1+=+me()+order+by+rand()+limit+'.$number_of_friends.')"}]';
$post_url = "https://graph.facebook.com/" . "?batch=" . urlencode($request) . "&access_token=" . $access_token . "&method=post";
$post = file_get_contents($post_url);
$decoded_response = json_decode($post, true);
$friends_json = $decoded_response[0]['body'];
$friends_data = json_decode($friends_json, true);
if (is_array($friends_data)) {
foreach ($friends_data as $friend) {
$selected_friend_ids[] = number_format($friend["uid"], 0, '.', ''); // Since there are exceptionally large id numbers
}
}
But this is problematic. It takes too long to receive a response from Facebook.
// Retrieve the locations of the user's friends using batched request
$i = 0;
$batched_request = array();
while ($i < ($number_of_friends/$number_of_friends_per_request)) {
$i++;
$friend_ids_variable_name = 'friend_ids_part_'.$i;
$$friend_ids_variable_name = array_slice($selected_friend_ids, ($i-1)*$number_of_friends_per_request, $number_of_friends_per_request);
if (!empty($$friend_ids_variable_name)) {
$api_string_ids_variable_name = 'api_string_ids_'.$i;
$$api_string_ids_variable_name = implode(',', $$friend_ids_variable_name);
$batched_request[] = array('method' => 'GET', 'relative_url' => '/locations?ids='.$$api_string_ids_variable_name);
}
}
$batch = $facebook->api('/?batch='.json_encode($batched_request), 'POST');
foreach ($batch as $batch_item) {
$body = $batch_item["body"];
$partial_friends_locations = json_decode($body, true);
foreach ($partial_friends_locations as $friend_id => $friend_locations_data) {
$friend_locations = $friend_locations_data["data"];
foreach ($friend_locations as $friend_location) {
// Process location information...
}
}
}
}
Is there a way to make the above request faster? I placed some codes to check the response time of the request and it is pretty slow.
For 100 friends, it takes > 20 seconds on average.
For 200 friends, it takes > 40 seconds on average.
For 400 friends, it takes > 80 seconds on average, and I sometimes receive an error message: "Error Code: 1 Message: An unknown error occurred"
To make things faster, it means:
Getting the same amount of information in less time, or
Getting more information for the same amount of time.

Answer 1

Why bother with batched requests? You can achieve everything with a single FQL multiquery:
{
"my_friends":
"SELECT uid, name FROM user WHERE uid IN
(SELECT uid2 FROM friend WHERE uid1 = me() ORDER BY rand() LIMIT 100)",
"their_locations":
"SELECT page_id, tagged_uids FROM location_post WHERE tagged_uids IN
(SELECT uid FROM #my_friends)",
"those_places":
"SELECT page_id, name, location FROM page WHERE page_id IN
(SELECT page_id FROM #their_locations"
}
In the API explorer, this runs in the 800-1200 ms range for me.
Another question: Why do you have the PHP SDK installed, but aren't using it to make these queries?

Answer 2

I too have noticed that facebook has a slow API response time. I have not actually developed a facebook application, but perhaps some of my learnings in dealing with the facebook like buttons and comment/share buttons will help you:
What I would suggest, is to lace your page with asynchronous api calls via javascript to get data. This way the page loads fast for your user, then it loads the facebook data in the background. You can accomplish this relatively easily with a library like jquery. Essentially you will break off the chunk of code that runs to process the data into another file and then run that with the jquery call.
Now that is the first part. The second part could be a little trick again to allow the user to perceive a faster application load time. Always load the first 100 friends first and display resulting data, and then query a second time (again using asynchronous calls), to finish querying for the rest of the users friends.
Again, this is speaking from more of a general perspective, but hopefully it will help!