Autocomplete for internal links for nivo slider link fields

We may not necessarily need the media_gallery module to include this. Below snippet is a proof of concept to use core autocomplete to help a user find internal links. It's subject to #93854: Allow autocompletion requests to include slashes (unless the module uses its own autocomplete.js) which will fix a problem with forward slashes, but it looks like that's due for inclusion in drupal 7.13

Better still, now we have #1524920: deprecate nivo-slider caption field in favor of description, it's fairly easy to add a read more button to the caption, such that it's appended to the nivo slider caption on node save/update when a link is present but not into the editable description, so we're not confusing users by altering their input. Attached screenshot shows a read more button on a nivo slider from another project, a similar style of read more button might work here?

function julio_slideshow_form_alter(&$form, &$form_state, $form_id) {
  if (strpos($form_id, 'media_edit_') === 0) {
    if (!isset($form['#after_build'])) {
      $form['#after_build'] = array();
    }
    $form['#after_build'][] = 'julio_slideshow_media_multiedit_form_after_build';
  }
}

function julio_slideshow_media_multiedit_form_after_build($form, &$form_state) {
  if ($form['media_nivo_slider_image_link']) {
      $form['media_nivo_slider_image_link']['und'][0]['value']['#autocomplete_path'] = 'julio_slideshow/autocomplete';
  }
  return $form;
}

function julio_slideshow_autocomplete($string = ''){
  $args = func_get_args();
  $string = implode('/', $args);
  $matches = array();
  if ($string) {
    $result = db_query_range("SELECT alias FROM {url_alias} WHERE (alias) LIKE :string", 0, 10, array(':string' => '%' . $string . '%'));
    foreach ($result as $record) {
      $matches[$record->alias] = check_plain($record->alias);
    }
  }
  print drupal_json_output($matches);
}

We could even feasibly check if the link is internal and pull a caption / title from a node if so... But I've changed my mind on that and actually think it's better to allow a custom one, because we do have very little space here and trimming would likely result in a non-sensical sentence.

autocomplete works quite nice:

actually, maybe doing this is better:

$result = db_query_range("SELECT nid, title, status FROM {node} WHERE (title) LIKE :string AND status = 1", 0, 10, array(':string' => '%' . $string . '%'));
    foreach ($result as $record) {
      $path = drupal_get_path_alias('node/' . $record->nid);
      $matches[$path] = check_plain($record->title . ' (' . $path . ')');
    }

This patch adds:

• An auto-complete helper for internal links, searching by title
• A helper to suggest a http:// prefix where absent for valid absolute links
• Inline indication of a bad absolute/relative url or no titles
• New title and description of the field to reflect the helper, removing references to nivo slider which may be confusing

Forgot the hook_menu, also, not sure why I used after_build here.

Setting this back to active as I'm sure the maintainers get the idea and I can't see it being committed (coding standards, the autocomplete being a bit convoluted etc.) even if fixes for the above added.

Patch now includes the relevant hook_menu

Also moved all the form alterations back into the form_alter, it didn't seem to make any difference in this scenario

Wrong patch... here's the right one.

The Drupal core fix that this patch relies on is present in the 7.14 release of yesterday