Using $this when not in object context - Laravel 4

Question

I have these two methods in my Contact.php model:

public function getSubscribers($listId)
{
    return $this->withTrashed()
        ->where(DB::raw("concat('',email * 1)"), '!=', DB::raw('email'))
        ->where('opt_out', '0')
        ->select('email')
        ->chunk(1000, function($results) use ($listId) { $this->subscribeEmails($listId, $results); });
}

public function subscribeEmails($listId, $subscribers)
{
    $emails = array();

    foreach ($subscribers as $key => $subscriber)
    {
        $memberActivity = $subscriber->memberActivity($listId);

        if ( ! $memberActivity['data'])
        {
            $emails[] = array('email' => $subscriber->email);
        }
        else
        {
            foreach ($memberActivity['data'] as $data)
            {
                foreach ($data['activity'] as $activity)
                {
                    if ($activity['action'] !== 'unsub')
                    {
                        $emails[] = array('email' => $subscriber->email);
                    }
                }
            }  
        }
    }

    MailchimpWrapper::lists()->batchSubscribe($listId, $emails, false, true);
}

And the getSubscribers() method is called in my AdminContactsController.php controller via a method called updateMailchimp():

public function updateMailchimp()
{
    $this->contact->getSubscribers($this->listId);

    $message = (object) array(
        'title'         => 'Excellent!',
        'content'       => 'The Mailchimp newsletter list has been updated with the latest contacts from within the system.',
        'alert_type'    => 'success'
    );

    return Redirect::back()->with('message', $message);
}

Locally, this works great, no problems at all but on the staging server, I get the following error referencing the line cotaining ->chunk(1000, function($results) use ($listId) { $this->subscribeEmails($listId, $results); });:

Using $this when not in object context

Is this a PHP version issue or am I missing something here?

Can you tell us, which line exactly do you get this error in? — matewka
– matewka, Commented Nov 28, 2013 at 10:10
Yeah man, it's ->chunk(1000, function($results) use ($listId) { $this->subscribeEmails($listId, $results); }); — Gareth Daine
– Gareth Daine, Commented Nov 28, 2013 at 10:14

matewka · Accepted Answer · 2013-11-28 10:28:49Z

2

The reason why your code works on localhost but not on the remote server is probably the difference in PHP versions. Before PHP 5.4.0 it is not possible to use $this from anonymous function. You must pass the reference to $this within the use keyword:

public function getSubscribers($listId)
{
    $that = $this; // <---- create reference to $this
    return $this->withTrashed()
        ->where(DB::raw("concat('',email * 1)"), '!=', DB::raw('email'))
        ->where('opt_out', '0')
        ->select('email')
        ->chunk(1000, function($results) use (&$that, $listId) { $this->subscribeEmails($listId, $results); });
}

edited Nov 28, 2013 at 10:28

answered Nov 28, 2013 at 10:17

matewka

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1 Comment

Gareth Daine Over a year ago

Yep, anlutro in Laravel chat got me on the right track and this is the correct answer. Cheers dude.

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