post on Facebook through cron job

I try to build an facebook auto poster for the own users wall (post as user to own wall). Therefor I have to do an facebook application through https://developers/facebook.com/apps. After I’ve defined the Secure Canvas URL I wrote the code for the index.php of the Secure Canvas URL to have the ability to post messages, links or pictures to the own users wall:

session_start();

require __DIR__ . '/autoload.php';

use Facebook\FacebookSession;
use Facebook\FacebookRequest;
use Facebook\GraphUser;
use Facebook\FacebookRequestException;
use Facebook\FacebookCanvasLoginHelper;
use Facebook\FacebookRedirectLoginHelper;

FacebookSession::setDefaultApplication('App-ID','App-Secret');

$helper = new FacebookCanvasLoginHelper();

$path = 'path/';

$message        = file_get_contents($path . 'message.php');
$description    = file_get_contents($path . 'description.php');
$link           = file_get_contents($path . 'link.php');
$picture        = file_get_contents($path . 'picture.php');

try {
    $session = $helper->getSession();
} catch (FacebookRequestException $ex) {
    echo $ex->getMessage();
} catch (\Exception $ex) {
    echo $ex->getMessage();
}

if (isset($session)) {
    try {

        // Doing a post
        if ($picture == '') {
            $response = (new FacebookRequest(
                $session, 'POST', '/me/feed', array(
                    'message' => $message,
                    'link' => $link,
                    'description' => $description
                )
            ))->execute()->getGraphObject();

        // Uploading a picture
        } else if ($picture != '') {
            $response = (new FacebookRequest(
                $session, 'POST', '/me/photos', array(  
                    'source' => new CURLFile($picture, 'image/jpg'),
                    'message' => $message
                )
            ))->execute()->getGraphObject();
        }
    } catch (FacebookRequestException $e) {
        echo $e->getMessage();
    }
} else {
    $helper = new FacebookRedirectLoginHelper('https://apps.facebook.com/App-Name/');
    $auth_url = $helper->getLoginUrl(array('email', 'publish_actions'));
    echo "<script>window.top.location.href='".$auth_url."'</script>";
}

When I’m calling the Secure-Canvas-URL/index.php everything is working well and the post appears on my wall. So now it was the task to write a php script named cron.php which calls the index.php file above to post on my wall without calling the Secure-Canvas-URL/index.php directly. I’ve done that via cURL:

facebookLogin('email', 'password');

// Function for logging in to facebook via cURL
function facebookLogin($email, $password) {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, 'https://www.facebook.com/login.php');
    curl_setopt($ch, CURLOPT_POSTFIELDS,'email='.urlencode($email).'&pass='.urlencode($password).'&login=Login');
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
    curl_setopt($ch, CURLOPT_COOKIEJAR, "cookies.txt");
    curl_setopt($ch, CURLOPT_COOKIEFILE, "cookies.txt");
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3");
    curl_setopt($ch, CURLOPT_REFERER, "http://www.facebook.com");
    $page = curl_exec($ch) or die(curl_error($ch));

    // Post on facebook
    facebookPost();
}

// Function for posting content through facebook via cURL
function facebookPost() {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, 'https://Secure-Canvas-URL/');
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($ch, CURLOPT_HEADER, 1);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
    curl_setopt($ch, CURLOPT_COOKIEJAR, "cookies.txt");
    curl_setopt($ch, CURLOPT_COOKIEFILE, "cookies.txt");
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3");
    $page = curl_exec($ch) or die(curl_error($ch));

}

When I’m calling the php file via http://example.com/cron.php the post appears on my wall. So this is working well, too. Now the php script has to be run through a cron job for automatically posting:

* * * * * /kunden/usr/bin/wget http://example.com/cron.php

The cron job calls the php script successfully which I tested by sending an email each minute. The problem is that the script cron.php isn’t able to post on my wall when it’s running by the cron job.

I suspect that I have to receive something from facebook which happens when I’m calling the Secure-Canvas-URL/index.php or http://example.com/cron.php in my browser but not when the cron is doing that job.