How to get all posts of a group via facebook graph api

Try this in PHP:

$response = file_get_contents("https://graph.facebook.com/$group_id/feed?limit=1000&access_token=$access_token");

It'll give you a page with a limit of 1000 posts. Convert the JSON response to a PHP associative array:

$array = json_decode($response, true);
// Do your own stuff with $array ...

Get the next page through:

$response = file_get_contents($array['paging']['next']);

Try this in a loop, until $array['data'] comes out as empty in the response.

---

Until - This is a UNIX time integer used to specify the point in time till which posts are to be fetched (only posts made after that will appear).

set_time_limit(99999999);
ini_set('memory_limit', "9999M");

function fetchUrl($url) {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_TIMEOUT, 40);
    
    $data = curl_exec($ch);
    curl_close($ch);
    
    return $data;
}

$url_array = array();

function recurse_it($url, $c) {
    global $url_array;
    $feeds         = fetchUrl($url);
    $feed_data_obj = json_decode($feeds, true);
    if (!empty($feed_data_obj['data'])) {
        $next_url      = $feed_data_obj['paging']['next'];
        $url_array[$c] = $next_url;
        recurse_it($next_url, $c + 1);
    }
    return $url_array;
}

$url = "https://graph.facebook.com/55259308085/groups?access_token=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
$arr = recurse_it($url, 0);
print_r($arr);

Where $arr is an array of all the available pagination links for which I used a foreach to loop through all the contents of the pagination.