background_batch.module in Background Process 8

This module adds background processing to Drupals batch API.

@todo Add option to stop a running batch job.

File

background_batch/background_batch.module

<?php

/**
 * @file
 * This module adds background processing to Drupals batch API.
 *
 * @todo Add option to stop a running batch job.
 */

/**
 * Default value for delay (in microseconds).
 */
use Drupal\Core\Url;
use Drupal\Component\Utility\Timer;
use Symfony\Component\HttpFoundation\RedirectResponse;

/**
 * Define Default value for Batch Delay (in miliseconds).
 */
const BACKGROUND_BATCH_DELAY = 1000000;

/**
 * Define Default value for process lifespan (in miliseconds).
 */
const BACKGROUND_BATCH_PROCESS_LIFESPAN = 10000;

/**
 * Define Default value wether ETA information should be shown.
 */
const BACKGROUND_BATCH_PROCESS_ETA = TRUE;

/**
 * Implements to Steal the operation and hook into context data.
 */
function background_batch_batch_alter(&$batch) {
  if ($batch['progressive'] && $batch['url'] == 'batch') {
    foreach ($batch['sets'] as &$set) {
      if (!empty($set['operations'])) {
        foreach ($set['operations'] as &$operation) {
          $operation = [
            '_background_batch_operation',
            [
              $operation,
            ],
          ];
        }
      }
    }
    $batch['timestamp'] = microtime(TRUE);
  }

  // In order to make this batch session independend we save the owner UID.
  $user = \Drupal::currentUser();
  $batch['uid'] = $user->uid;
}

/**
 * Implements hook_library().
 */
function background_batch_library() {
  $libraries = [];
  $libraries['background-process.batch'] = [
    'title' => 'Background batch API',
    'version' => '1.0.0',
    'js' => [
      drupal_get_path('module', 'background_batch') . '/js/batch.js' => [
        'group' => JS_DEFAULT,
        'cache' => FALSE,
      ],
    ],
    'dependencies' => [
      [
        'background_batch',
        'background-process.progress',
      ],
    ],
  ];
  $libraries['background-process.progress'] = [
    'title' => 'Background batch progress',
    'version' => VERSION,
    'js' => [
      drupal_get_path('module', 'background_batch') . '/js/progress.js' => [
        'group' => JS_DEFAULT,
        'cache' => FALSE,
      ],
    ],
  ];
  return $libraries;
}

/**
 * Implements to Run a batch operation with "listening" context.
 */
function _background_batch_operation($operation, &$context) {

  // Steal context and trap finished variable.
  $fine_progress = !empty($context['sandbox']['background_batch_fine_progress']);
  if ($fine_progress) {
    $batch_context = new BackgroundBatchContext($context);
  }
  else {
    $batch_context = $context;
  }

  // Call the original operation.
  $operation[1][] =& $batch_context;
  call_user_func_array($operation[0], $operation[1]);
  if ($fine_progress) {

    // Transfer back context result to batch api.
    $batch_context = (array) $batch_context;
    foreach (array_keys($batch_context) as $key) {
      $context[$key] = $batch_context[$key];
    }
  }
  else {
    $batch_context = new BackgroundBatchContext($context);
    $batch_context['finished'] = $context['finished'];
  }
}

/**
 * Implements to Process a batch step.
 */
function _background_batch_process($id = NULL) {
  if (!$id) {
    return;
  }

  // Retrieve the current state of batch from db.
  $data = db_query("SELECT batch FROM {batch} WHERE bid = :bid", [
    ':bid' => $id,
  ])
    ->fetchColumn();
  if (!$data) {
    return;
  }
  require_once 'includes/batch.inc';
  $batch =& batch_get();
  $batch = unserialize($data);

  // Check if the current user owns (has access to) this batch.
  $user = \Drupal::currentUser();
  if ($batch['uid'] != $user->uid) {
    return drupal_access_denied();
  }

  // Register database update for the end of processing.
  drupal_register_shutdown_function('_batch_shutdown');
  Timer['start']['$id']['background_batch_processing'];
  $percentage = 0;
  $mem_max_used = 0;
  $mem_last_used = memory_get_usage();
  $mem_limit = ini_get('memory_limit');
  preg_match('/(\\d+)(\\w)/', $mem_limit, $matches);
  switch ($matches[2]) {
    case 'M':
    default:
      $mem_limit = $matches[1] * 1024 * 1024;
      break;
  }
  while ($percentage < 100) {
    list($percentage) = _batch_process();
    $mem_used = memory_get_usage();

    // If we memory usage of last run will exceed the
    // memory limit in next run then bail out.
    if ($mem_limit < $mem_used + $mem_last_used) {
      break;
    }
    $mem_last_used = $mem_used - $mem_last_used;

    // If we maximum memory usage of previous runs will exceed
    // the memory limit in next run then bail out.
    $mem_max_used = $mem_max_used < $mem_last_used ? $mem_last_used : $mem_max_used;
    if ($mem_limit < $mem_used + $mem_max_used) {
      break;
    }
    if (Timer['read']['background_batch_processing'] > \Drupal::config('background_batch.settings')
      ->get('background_batch_process_lifespan')) {
      break;
    }
  }
  if ($percentage < 100) {
    background_process_keepalive($id);
  }
}

/**
 * Implements to Processes the batch.
 */
function background_batch_process_batch($redirect = NULL, $url = 'batch', $redirect_callback = '') {
  $batch =& batch_get();
  if (isset($batch)) {

    // Add process information.
    $process_info = [
      'current_set' => 0,
      'progressive' => TRUE,
      'url' => $url,
      'url_options' => [],
      'source_url' => $_GET['q'],
      'redirect' => $redirect,
      'theme' => \Drupal::theme()
        ->getActiveTheme()
        ->getName(),
      'redirect_callback' => isset($redirect_callback) ? RedirectResponse('/admin/config/system/batch/overview') : '',
    ];
    $batch += $process_info;

    // The batch is now completely built.
    // Allow other modules to make changes.
    \Drupal::moduleHandler()
      ->alter('batch', $batch);

    // Assign an arbitrary id: don't rely
    // on a serial column in the 'batch'.
    $batch['id'] = db_next_id();

    // Move operations to a job queue.
    // Non-progressive batches will use a memory-based queue.
    foreach ($batch['sets'] as $key => $batch_set) {
      _batch_populate_queue($batch, $key);
    }
    $t = 't';
    $batch['error_message'] = $t('Please continue to <a href="@error_url">the error page</a>', [
      '@error_url' => Url::fromUri($url, [
        'query' => [
          'id' => $batch['id'],
          'op' => 'finished',
        ],
      ]),
    ]);
    if (isset($_GET['destination'])) {
      $batch['destination'] = $_GET['destination'];
      unset($_GET['destination']);
    }

    // Store the batch.
    db_insert('batch')
      ->fields([
      'bid' => $batch['id'],
      'timestamp' => REQUEST_TIME,
      'token' => drupal_get_token($batch['id']),
      'batch' => serialize($batch),
    ])
      ->execute();

    // Set the batch number in the session
    // to guarantee that it will stay alive.
    $_SESSION['batches'][$batch['id']] = TRUE;

    // Redirect for processing.
    $function = $batch['redirect_callback'];
    return $function;
  }
  background_process_start('_background_batch_process_callback', $batch);
}

/**
 * Implements For Batch Process Callback.
 */
function _background_batch_process_callback($batch) {
  $rbatch =& batch_get();
  $rbatch = $batch;
  require_once 'background_batch.pages.inc';
  _background_batch_page_start();
}

/**
 * Implements hook_menu_links_discovered_alter().
 */
function background_batch_menu_links_discovered_alter(array &$links) {
}

/**
 * Implements hook_menu_local_tasks_alter().
 */
function background_batch_menu_local_tasks_alter(array &$data, $route_name) {
}

/**
 * Implements hook_menu_local_actions_alter().
 */
function background_batch_menu_local_actions_alter(array &$local_actions) {
}

/**
 * Implements hook_contextual_links_view_alter().
 */
function background_batch_contextual_links_view_alter(array &$element, array $items) {
}

Functions

Name	Description
background_batch_batch_alter	Implements to Steal the operation and hook into context data.
background_batch_contextual_links_view_alter	Implements hook_contextual_links_view_alter().
background_batch_library	Implements hook_library().
background_batch_menu_links_discovered_alter	Implements hook_menu_links_discovered_alter().
background_batch_menu_local_actions_alter	Implements hook_menu_local_actions_alter().
background_batch_menu_local_tasks_alter	Implements hook_menu_local_tasks_alter().
background_batch_process_batch	Implements to Processes the batch.
_background_batch_operation	Implements to Run a batch operation with "listening" context.
_background_batch_process	Implements to Process a batch step.
_background_batch_process_callback	Implements For Batch Process Callback.

Constants

Name	Description
BACKGROUND_BATCH_DELAY	Define Default value for Batch Delay (in miliseconds).
BACKGROUND_BATCH_PROCESS_ETA	Define Default value wether ETA information should be shown.
BACKGROUND_BATCH_PROCESS_LIFESPAN	Define Default value for process lifespan (in miliseconds).