function batch_example_op_2 in Examples for Developers 6

Same name and namespace in other branches

1. 8 batch_example/batch_example.module \batch_example_op_2()
2. 7 batch_example/batch_example.module \batch_example_op_2()
3. 3.x modules/batch_example/batch_example.module \batch_example_op_2()

Batch operation for batch 2 : load all nodes, 5 by five This is a multipart operation, using the

Related topics

1 string reference to 'batch_example_op_2'

batch_example_batch_2 in batch_example/batch_example.module

Batch 2 : load all nodes 5 by 5, 20 times (Multipart operation)

File

batch_example/batch_example.module, line 235

This is an example outlining how a module can define batches.

Code

function batch_example_op_2(&$context) {

  // Use the $context['sandbox'] at your convenience to store the
  // information needed to track progression between successive calls.
  if (!isset($context['sandbox']['progress'])) {
    $context['sandbox']['progress'] = 0;
    $context['sandbox']['current_node'] = 0;
    $context['sandbox']['max'] = db_result(db_query('SELECT COUNT(DISTINCT nid) FROM {node}'));
  }

  // Process nodes by groups of 5 (arbitrary value).
  // When a group of five 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 = 5;

  // Retrieve the next group of nids.
  $result = db_query_range("SELECT nid FROM {node} WHERE nid > %d ORDER BY nid ASC", $context['sandbox']['current_node'], 0, $limit);
  while ($row = db_fetch_array($result)) {

    // Here we actually perform our dummy 'processing' on the current node.
    $node = node_load($row['nid'], NULL, TRUE);

    // Store some result for post-processing in the finished callback.
    $context['results'][] = $node->nid . ' : ' . check_plain($node->title);

    // Update our progress information.
    $context['sandbox']['progress']++;
    $context['sandbox']['current_node'] = $node->nid;
    $context['message'] = check_plain($node->title);
  }

  // Inform the batch engine that we are not finished,
  // and provide an estimation of the completion level we reached.
  if ($context['sandbox']['progress'] >= $context['sandbox']['max']) {

    // We should always check if the current progress is equal or greater to
    // the total number of items to process. For example, if a node is added
    // while this batch process is running, the progress value will end up being
    // one greater than the max value. This will cause an infinite loop. We
    // prevent this from happening by always checking if progress is greater
    // than or equal to max.
    $context['finished'] = 1;
  }
  else {
    $context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
  }
}