batch_example.install

<?php


/**
 * @file
 * Install, update, and uninstall functions for the batch_example module.
 */

/**
 * Example of batch-driven update function.
 *
 * Because some update functions may require the batch API, the $sandbox
 * provides a place to store state. When $sandbox['#finished'] == TRUE,
 * calls to this update function are completed.
 *
 * The $sandbox param provides a way to store data during multiple invocations.
 * When the $sandbox['#finished'] == 1, execution is complete.
 *
 * This dummy 'update' function changes no state in the system. It simply
 * loads each node.
 *
 * To make this update function run again and again, execute the query
 * "update system set schema_version = 0 where name = 'batch_example';"
 * and then run /update.php.
 *
 * @ingroup batch_example
 */
function batch_example_update_8001(&$sandbox) {
    $db_connection = \Drupal::database();
    // Use the sandbox at your convenience to store the information needed
    // to track progression between successive calls to the function.
    if (!isset($sandbox['progress'])) {
        // The count of nodes visited so far.
        $sandbox['progress'] = 0;
        // Total nodes that must be visited.
        $sandbox['max'] = $db_connection->query('SELECT COUNT(nid) FROM {node}')
            ->fetchField();
        // A place to store messages during the run.
        $sandbox['messages'] = [];
        // Last node read via the query.
        $sandbox['current_node'] = -1;
    }
    // Process nodes by groups of 10 (arbitrary value).
    // When a group is processed, the batch update engine determines
    // whether it should continue processing in the same request or provide
    // progress feedback to the user and wait for the next request.
    $limit = 10;
    // Retrieve the next group of nids.
    $query = $db_connection->select('node', 'n');
    $query->fields('n', [
        'nid',
    ]);
    $result = $query->where('n.nid > :nid', [
        ':nid' => $sandbox['current_node'],
    ])
        ->range(0, $limit)
        ->orderBy('n.nid', 'ASC')
        ->execute();
    foreach ($result as $row) {
        // Here we actually perform a dummy 'update' on the current node.
        $node = $db_connection->query('SELECT nid FROM {node} WHERE nid = :nid', [
            ':nid' => $row->nid,
        ])
            ->fetchField();
        // Update our progress information.
        $sandbox['progress']++;
        $sandbox['current_node'] = $row->nid;
    }
    // Set the "finished" status, to tell batch engine whether this function
    // needs to run again. If you set a float, this will indicate the progress
    // of the batch so the progress bar will update.
    $sandbox['#finished'] = $sandbox['progress'] >= $sandbox['max'] ? TRUE : $sandbox['progress'] / $sandbox['max'];
    // Set up a per-run message; Make a copy of $sandbox so we can change it.
    // This is simply a debugging stanza to illustrate how to capture status
    // from each pass through hook_update_N().
    $sandbox_status = $sandbox;
    // Don't want them in the output.
    unset($sandbox_status['messages']);
    $sandbox['messages'][] = t('$sandbox=') . print_r($sandbox_status, TRUE);
    if ($sandbox['#finished']) {
        // hook_update_N() may optionally return a string which will be displayed
        // to the user.
        $final_message = '<ul><li>' . implode('</li><li>', $sandbox['messages']) . "</li></ul>";
        return t('The batch_example demonstration update did what it was supposed to do: @message', [
            '@message' => $final_message,
        ]);
    }
}