Allow altering path_alias_xt inbound url

Here's a use case for this patch. I want to limit the path_alias_xt from working on all other paths, except if they have "slide/1" on the end, for example. That way, if I have a valid url such as "videos", an extended alias that I don't want, such as "videos/my-random-string" will 404, as it should. Right now, out of the box, path_alias_xt doesn't have a way to limit this. This is why I'm proposing an alter hook.

This is how I'm planning to use it, in another module called path_alias_xt_limiter:

function path_alias_xt_limiter_path_alias_xt_url_inbound_path_alter(&$path, $original_path, $path_language) {
  
  if($path != $original_path) {
      
    if (preg_match('/\/slide\/(.+)$/',$path, $matches)) {
      $slide_number = $matches[1];
      
      if (!is_numeric($slide_number) || $slide_number < 2) {
        $base_path = preg_replace('/\/slide\/(.+)$/', '', $path);
        drupal_goto($base_path, array(), '301');
      }
      
      if ($slide_number && path_alias_xt_limiter_is_valid_slide($slide_number, $path)) {
        return $path;
      }
    } else { // if the path doesn't have /slide/<some number> in it, undo path_alias_xt changes
      $path = $original_path;
    }
      
  }
  
}

function path_alias_xt_limiter_is_valid_slide($slide_number, $drupal_path) {

  if (preg_match('/node\/([0-9]+)/',$drupal_path,$matches)) {
    $nid = $matches[1];
    $node = node_load($nid);
    
    if ($node->type == 'gallery' && isset($node->field_gallery_images[LANGUAGE_NONE][$slide_number]['value'])) {
      return TRUE;
    }

  }
  return FALSE;
}

Rik,

Yes, you're right. As long as the module weight is lower. So if path_alias_xt is -1, my module that makes changes needs a lower weight to fire after it, say -2. In this case, the patch isn't needed. It needs to be lower because drupal_get_normal_path runs the modules in reverse order.

from drupal_get_normal_path:

  // Allow other modules to alter the inbound URL. We cannot use drupal_alter()
  // here because we need to run hook_url_inbound_alter() in the reverse order
  // of hook_url_outbound_alter().
  foreach (array_reverse(module_implements('url_inbound_alter')) as $module) {
    $function = $module . '_url_inbound_alter';
    $function($path, $original_path, $path_language);
  }

I had the purl module enabled which was changing the $original_path variable, so I thought I couldn't do it with a simple hook_url_inbound_alter, but I think that's just an issue with the purl module, that was causing the $original_path variable to change before getting to my custom module.