cron_example.module in Examples for Developers 8

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

File

cron_example/cron_example.module

<?php

/**
 * @file
 * Demonstrates use of the Cron API in Drupal - hook_cron().
 */

/**
 * @defgroup cron_example Example: Cron
 * @ingroup examples
 * @{
 * Example using Cron API, including hook_cron() and @QueueWorker plugins
 *
 * This example is part of the Examples for Developers Project
 * which you can download and experiment with at
 * http://drupal.org/project/examples
 */

/**
 * 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.
 */
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);
  }
}

/**
 * @} End of "defgroup cron_example".
 */

Functions

Name	Description
cron_example_cron	Implements hook_cron().