502 Bad Gateway Foreach loop - php

Question

hope for some help, basically i have a script that gets the latest posts from facebook users, and basically i check if there is any new post that is not available on my database, in case that this post is new, than i save it in my database along with the post id (this way i check if exist on DB).
But i have a issue with it, in my case i need to check a number of users, and this users keeps growing, in my case i have 400 users. If i go more thatn 100 users i get the 500 error of course, it is many requests.
So does someone have a ideia of how could i handle it?
My code: FarcebookParcer.php
public function facebook($id, $num) {
//Set your App ID and App Secret.
$appID = 'xxxxxxxxxx';
$appSecret = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxx';
//Create an access token using the APP ID and APP Secret.
$accessToken = $appID . '|' . $appSecret;
//Tie it all together to construct the URL
$url = "https://graph.facebook.com/$id/posts?fields=attachments,created_time&limit=$num&access_token=$accessToken";
if (Helper::get_http_response_code($url) != 200) {
return false;
}
//Make the API call
$opts = array(
'http' => array(
'method' => 'GET',
'timeout' => 120
)
);
$context = stream_context_create($opts);
$result = file_get_contents($url, false, $context);
//Decode the JSON result.
$dt = json_decode($result, true);
$posts = $dt;
return $posts;
}
CronController.php
public function socialfacebook() {
$facebook = SocialSnap::all();
$socialparser = new FacebookParser();
$appID = 'xxxxxxxxxxx';
$appSecret = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
$accessToken = $appID . '|' . $appSecret;
set_time_limit(0);
foreach ($facebook as $key => $value) {
if ($value->facebook != NULL) {
$facebook_user = $socialparser->facebook_user(substr($value->facebook, 1));
$facebook_posts = $socialparser->facebook(substr($value->facebook, 1), 1);
//Check if valid url
if ($facebook_posts == false || $facebook_user == false) {
continue;
}
if (isset($facebook_posts['data'][0]['attachments']['data'][0]['target']['url']) && isset($facebook_posts['data'][0]['attachments']['data'][0]['description'])) {
SnapChat::where('facebook', $value->facebook)->update(['facebook_photo' => 'https://graph.facebook.com/'. substr($value->facebook, 1) . '/picture/?type=normal']);
$post_current = SocialSnap::where('id_social', $facebook_posts['data'][0]['id'])->first();
//return $post_current;
if ($post_current == NULL) {
$post = new SocialSnap;
$post->id_social = $facebook_posts['data'][0]['id'];
$post->id_snapchats = $value->id;
$post->date_social = isset($facebook_posts['data'][0]['created_time']) ? date("Y-m-d H:m:s", strtotime($facebook_posts['data'][0]['created_time'])) : "";
$post->type = 'facebook';
$post->url = $facebook_posts['data'][0]['attachments']['data'][0]['target']['url'];
$post->message = $facebook_posts['data'][0]['attachments']['data'][0]['description'];
if (isset($facebook_posts['data'][0]['attachments']['data'][0]['media']['image']['src'])) {
$post->image = $facebook_posts['data'][0]['attachments']['data'][0]['media']['image']['src'];
}
$post->save();
}
}
}
}
echo 'DONE';
}