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 hook_cron_queue_info().
 *
 * 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_menu().
 */
function cron_example_menu() {
    $items['examples/cron_example'] = array(
        'title' => 'Cron Example',
        'page callback' => 'drupal_get_form',
        'page arguments' => array(
            'cron_example_form',
        ),
        'access callback' => TRUE,
    );
    return $items;
}

/**
 * The form to provide a link to cron.php.
 */
function cron_example_form($form, &$form_state) {
    $form['status'] = array(
        '#type' => 'fieldset',
        '#title' => t('Cron status information'),
    );
    $form['status']['intro'] = array(
        '#markup' => '<div>' . t('The cron example demonstrates hook_cron() and hook_cron_queue_info() processing. If you have administrative privileges you can run cron from this page and see the results.') . '</div>',
    );
    $form['status']['last'] = array(
        '#markup' => '<div>' . t('cron_example_cron() will next execute the first time cron runs after %time (%seconds seconds from now)', array(
            '%time' => date_iso8601(variable_get('cron_example_next_execution', time())),
            '%seconds' => variable_get('cron_example_next_execution', time()) - time(),
        )) . '</div>',
    );
    if (user_access('administer site configuration')) {
        $form['cron_run'] = array(
            '#type' => 'fieldset',
            '#title' => t('Run cron manually'),
        );
        $form['cron_run']['cron_reset'] = array(
            '#type' => 'checkbox',
            '#title' => t("Run cron_example's cron regardless of whether interval has expired."),
            '#default_value' => FALSE,
        );
        $form['cron_run']['cron_trigger'] = array(
            '#type' => 'submit',
            '#value' => t('Run cron now'),
            '#submit' => array(
                'cron_example_form_cron_run_submit',
            ),
        );
    }
    $form['cron_queue_setup'] = array(
        '#type' => 'fieldset',
        '#title' => t('Cron queue setup (for hook_cron_queue_info(), etc.)'),
    );
    $queue_1 = DrupalQueue::get('cron_example_queue_1');
    $queue_2 = DrupalQueue::get('cron_example_queue_2');
    $form['cron_queue_setup']['current_cron_queue_status'] = array(
        '#markup' => '<div>' . t('There are currently %queue_1 items in queue 1 and %queue_2 items in queue 2', array(
            '%queue_1' => $queue_1->numberOfItems(),
            '%queue_2' => $queue_2->numberOfItems(),
        )) . '</div>',
    );
    $form['cron_queue_setup']['num_items'] = array(
        '#type' => 'select',
        '#title' => t('Number of items to add to queue'),
        '#options' => drupal_map_assoc(array(
            1,
            5,
            10,
            100,
            1000,
        )),
        '#default_value' => 5,
    );
    $form['cron_queue_setup']['queue'] = array(
        '#type' => 'radios',
        '#title' => t('Queue to add items to'),
        '#options' => array(
            'cron_example_queue_1' => t('Queue 1'),
            'cron_example_queue_2' => t('Queue 2'),
        ),
        '#default_value' => 'cron_example_queue_1',
    );
    $form['cron_queue_setup']['submit'] = array(
        '#type' => 'submit',
        '#value' => t('Add jobs to queue'),
        '#submit' => array(
            'cron_example_add_jobs_to_queue',
        ),
    );
    $form['configuration'] = array(
        '#type' => 'fieldset',
        '#title' => t('Configuration of cron_example_cron()'),
    );
    $form['configuration']['cron_example_interval'] = array(
        '#type' => 'select',
        '#title' => t('Cron interval'),
        '#description' => t('Time after which cron_example_cron will respond to a processing request.'),
        '#default_value' => variable_get('cron_example_interval', 60 * 60),
        '#options' => array(
            60 => t('1 minute'),
            300 => t('5 minutes'),
            3600 => t('1 hour'),
            60 * 60 * 24 => t('1 day'),
        ),
    );
    return system_settings_form($form);
}

/**
 * Allow user to directly execute cron, optionally forcing it.
 */
function cron_example_form_cron_run_submit($form, &$form_state) {
    if (!empty($form_state['values']['cron_reset'])) {
        variable_set('cron_example_next_execution', 0);
    }
    // We don't usually use globals in this way. This is used here only to
    // make it easy to tell if cron was run by this form.
    $GLOBALS['cron_example_show_status_message'] = TRUE;
    if (drupal_cron_run()) {
        drupal_set_message(t('Cron ran successfully.'));
    }
    else {
        drupal_set_message(t('Cron run failed.'), 'error');
    }
}

/**
 * Submit function used to add the items to the queue.
 */
function cron_example_add_jobs_to_queue($form, &$form_state) {
    $queue = $form_state['values']['queue'];
    $num_items = $form_state['values']['num_items'];
    $queue = DrupalQueue::get($queue);
    for ($i = 1; $i <= $num_items; $i++) {
        $item = new stdClass();
        $item->created = time();
        $item->sequence = $i;
        $queue->createItem($item);
    }
}

/**
 * Implements hook_cron().
 *
 * hook_cron() is the traditional (pre-Drupal 7) hook for doing "background"
 * processing. It gets called every time the Drupal cron runs and must decide
 * what it will do.
 *
 * In this example, it does a watchdog() call after the time named in
 * the variable 'cron_example_next_execution' has arrived, and then it
 * resets that variable to a time in the future.
 */
function cron_example_cron() {
    // Default to an hourly interval. Of course, cron has to be running at least
    // hourly for this to work.
    $interval = variable_get('cron_example_interval', 60 * 60);
    // We usually don't want to act every time cron runs (which could be every
    // minute) so keep a time for the next run in a variable.
    if (time() >= variable_get('cron_example_next_execution', 0)) {
        // This is a silly example of a cron job.
        // It just makes it obvious that the job has run without
        // making any changes to your database.
        watchdog('cron_example', 'cron_example ran');
        if (!empty($GLOBALS['cron_example_show_status_message'])) {
            drupal_set_message(t('cron_example executed at %time', array(
                '%time' => date_iso8601(time(0)),
            )));
        }
        variable_set('cron_example_next_execution', time() + $interval);
    }
}

/**
 * Implements hook_cron_queue_info().
 *
 * hook_cron_queue_info() and family are new since Drupal 7, and allow any
 * process to add work to the queue to be acted on when cron runs. Queues are
 * described and worker callbacks are provided, and then only the worker
 * callback needs to be implemented.
 *
 * All the details of queue use are done by the cron_queue implementation, so
 * one doesn't need to know much about DrupalQueue().
 *
 * @see queue_example.module
 */
function cron_example_cron_queue_info() {
    $queues['cron_example_queue_1'] = array(
        'worker callback' => 'cron_example_queue_1_worker',
        // One second max runtime per cron run.
'time' => 1,
    );
    $queues['cron_example_queue_2'] = array(
        'worker callback' => 'cron_example_queue_2_worker',
        'time' => 10,
    );
    return $queues;
}

/**
 * Simple worker for our queues.
 *
 * @param object $item
 *   Any object to be worked on.
 */
function cron_example_queue_1_worker($item) {
    cron_example_queue_report_work(1, $item);
}

/**
 * Simple worker for our queues.
 *
 * @param object $item
 *   Any object to be worked on.
 */
function cron_example_queue_2_worker($item) {
    cron_example_queue_report_work(2, $item);
}

/**
 * Simple reporter for the workers.
 *
 * @param int $worker
 *   Worker number.
 * @param object $item
 *   The $item which was stored in the cron queue.
 */
function cron_example_queue_report_work($worker, $item) {
    if (!empty($GLOBALS['cron_example_show_status_message'])) {
        drupal_set_message(t('Queue @worker worker processed item with sequence @sequence created at @time', array(
            '@worker' => $worker,
            '@sequence' => $item->sequence,
            '@time' => date_iso8601($item->created),
        )));
    }
    watchdog('cron_example', 'Queue @worker worker processed item with sequence @sequence created at @time', array(
        '@worker' => $worker,
        '@sequence' => $item->sequence,
        '@time' => date_iso8601($item->created),
    ));
}

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