Menu callback; Shared Ajax callback for file uploads and deletions.

This rebuilds the form element for a particular field item. As long as the form processing is properly encapsulated in the widget element the form should rebuild correctly using FAPI without the need for additional callbacks or processing.

File

drupal-7.x/modules/file/file.module, line 237

Defines a "managed_file" Form API field and a "file" field for Field module.

Code

function file_ajax_upload() {
  $form_parents = func_get_args();
  $form_build_id = (string) array_pop($form_parents);

  if (empty($_POST['form_build_id']) || $form_build_id != $_POST['form_build_id']) {
    // Invalid request.
    drupal_set_message(t('An unrecoverable error occurred. The uploaded file likely exceeded the maximum file size (@size) that this server supports.', array('@size' => format_size(file_upload_max_size()))), 'error');
    $commands = array();
    $commands[] = ajax_command_replace(NULL, theme('status_messages'));
    return array('#type' => 'ajax', '#commands' => $commands);
  }

  list($form, $form_state) = ajax_get_form();

  if (!$form) {
    // Invalid form_build_id.
    drupal_set_message(t('An unrecoverable error occurred. Use of this form has expired. Try reloading the page and submitting again.'), 'error');
    $commands = array();
    $commands[] = ajax_command_replace(NULL, theme('status_messages'));
    return array('#type' => 'ajax', '#commands' => $commands);
  }

  // Get the current element and count the number of files.
  $current_element = $form;
  foreach ($form_parents as $parent) {
    $current_element = $current_element[$parent];
  }
  $current_file_count = isset($current_element['#file_upload_delta']) ? $current_element['#file_upload_delta'] : 0;

  // Process user input. $form and $form_state are modified in the process.
  drupal_process_form($form['#form_id'], $form, $form_state);

  // Retrieve the element to be rendered.
  foreach ($form_parents as $parent) {
    $form = $form[$parent];
  }

  // Add the special Ajax class if a new file was added.
  if (isset($form['#file_upload_delta']) && $current_file_count < $form['#file_upload_delta']) {
    $form[$current_file_count]['#attributes']['class'][] = 'ajax-new-content';
  }
  // Otherwise just add the new content class on a placeholder.
  else {
    $form['#suffix'] .= '<span class="ajax-new-content"></span>';
  }

  $output = theme('status_messages') . drupal_render($form);
  $js = drupal_add_js();
  $settings = call_user_func_array('array_merge_recursive', $js['settings']['data']);

  $commands = array();
  $commands[] = ajax_command_replace(NULL, $output, $settings);
  return array('#type' => 'ajax', '#commands' => $commands);
}