<?php
/**
* @file
* Callbacks provided by the form system.
*/
/**
* @addtogroup callbacks
* @{
*/
/**
* Perform a single batch operation.
*
* Callback for batch_set().
*
* @param $MULTIPLE_PARAMS
* Additional parameters specific to the batch. These are specified in the
* array passed to batch_set().
* @param $context
* The batch context array, passed by reference. This contains the following
* properties:
* - 'finished': A float number between 0 and 1 informing the processing
* engine of the completion level for the operation. 1 (or no value
* explicitly set) means the operation is finished: the operation will not
* be called again, and execution passes to the next operation or the
* callback_batch_finished() implementation. Any other value causes this
* operation to be called again; however it should be noted that the value
* set here does not persist between executions of this callback: each time
* it is set to 1 by default by the batch system.
* - 'sandbox': This may be used by operations to persist data between
* successive calls to the current operation. Any values set in
* $context['sandbox'] will be there the next time this function is called
* for the current operation. For example, an operation may wish to store a
* pointer in a file or an offset for a large query. The 'sandbox' array key
* is not initially set when this callback is first called, which makes it
* useful for determining whether it is the first call of the callback or
* not:
* @code
* if (empty($context['sandbox'])) {
* // Perform set-up steps here.
* }
* @endcode
* The values in the sandbox are stored and updated in the database between
* http requests until the batch finishes processing. This avoids problems
* if the user navigates away from the page before the batch finishes.
* - 'message': A text message displayed in the progress page.
* - 'results': The array of results gathered so far by the batch processing.
* This array is highly useful for passing data between operations. After
* all operations have finished, this is passed to callback_batch_finished()
* where results may be referenced to display information to the end-user,
* such as how many total items were processed.
*/
function callback_batch_operation($MULTIPLE_PARAMS, &$context) {
if (!isset($context['sandbox']['progress'])) {
$context['sandbox']['progress'] = 0;
$context['sandbox']['current_node'] = 0;
$context['sandbox']['max'] = db_query('SELECT COUNT(DISTINCT nid) FROM {node}')->fetchField();
}
// For this example, we decide that we can safely process
// 5 nodes at a time without a timeout.
$limit = 5;
// With each pass through the callback, 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 processing on the current node.
$node = node_load($row['nid'], NULL, TRUE);
$node->value1 = $options1;
$node->value2 = $options2;
node_save($node);
// Store some result for post-processing in the finished callback.
$context['results'][] = check_plain($node->title);
// Update our progress information.
$context['sandbox']['progress']++;
$context['sandbox']['current_node'] = $node->nid;
$context['message'] = t('Now processing %node', array('%node' => $node->title));
}
// Inform the batch engine that we are not finished,
// and provide an estimation of the completion level we reached.
if ($context['sandbox']['progress'] != $context['sandbox']['max']) {
$context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
}
}
/**
* Complete a batch process.
*
* Callback for batch_set().
*
* This callback may be specified in a batch to perform clean-up operations, or
* to analyze the results of the batch operations.
*
* @param $success
* A boolean indicating whether the batch has completed successfully.
* @param $results
* The value set in $context['results'] by callback_batch_operation().
* @param $operations
* If $success is FALSE, contains the operations that remained unprocessed.
*/
function callback_batch_finished($success, $results, $operations) {
if ($success) {
// Here we do something meaningful with the results.
$message = t("!count items were processed.", array(
'!count' => count($results),
));
$message .= theme('item_list', array('items' => $results));
drupal_set_message($message);
}
else {
// An error occurred.
// $operations contains the operations that remained unprocessed.
$error_operation = reset($operations);
$message = t('An error occurred while processing %error_operation with arguments: @arguments', array(
'%error_operation' => $error_operation[0],
'@arguments' => print_r($error_operation[1], TRUE)
));
drupal_set_message($message, 'error');
}
}