<?php
$fb = new Facebook\Facebook([
    'app_id' => '{app-id}',
    'app_secret' => '{app-secret}',
    'default_graph_version' => 'v2.8'
]);
$accessToken = $fb->getApp()->getAccessToken();

try {
    $response = $fb->get('/{page-id}/posts?fields=id,link,message,full_picture,created_time', $accessToken);
    $items = $response->getDecodedBody();
} catch(\Facebook\Exceptions\FacebookResponseException $e) {
    // When Graph returns an error
    echo 'Graph returned an error: ' . $e->getMessage();
    exit;
} catch(\Facebook\Exceptions\FacebookSDKException $e) {
    // When validation fails or other local issues
    echo 'Facebook SDK returned an error: ' . $e->getMessage();
    exit;
}