function cron_example_cron in Examples for Developers 8

Same name and namespace in other branches

1. 7 cron_example/cron_example.module \cron_example_cron()
2. 3.x modules/cron_example/cron_example.module \cron_example_cron()

Implements hook_cron().

We implement hook_cron() to do "background" processing. It gets called every time the Drupal cron runs. We then decide what has to happen in response.

In this example, we log a message after the time given in the state value 'cron_example.next_execution'. Then we update that variable to a time in the future.

Related topics

File

cron_example/cron_example.module, line 29

Demonstrates use of the Cron API in Drupal - hook_cron().

Code

function cron_example_cron() {

  // We access our configuration.
  $cron_config = \Drupal::config('cron_example.settings');

  // Default to an hourly interval. Of course, cron has to be running at least
  // hourly for this to work.
  $interval = $cron_config
    ->get('interval');
  $interval = !empty($interval) ? $interval : 3600;

  // We usually don't want to act every time cron runs (which could be every
  // minute) so keep a time for the next run in the site state.
  $next_execution = \Drupal::state()
    ->get('cron_example.next_execution', 0);
  if (REQUEST_TIME >= $next_execution) {

    // This is a silly example of a cron job.
    // It just makes it obvious that the job has run without
    // making any changes to your database.
    \Drupal::logger('cron_example')
      ->notice('cron_example ran');
    if (\Drupal::state()
      ->get('cron_example_show_status_message')) {
      \Drupal::messenger()
        ->addMessage(t('cron_example executed at %time', [
        '%time' => date('c'),
      ]));
      \Drupal::state()
        ->set('cron_example_show_status_message', FALSE);
    }
    \Drupal::state()
      ->set('cron_example.next_execution', REQUEST_TIME + $interval);
  }
}