[Drupal] How to get the real path of a node, no matter it is a path or a url alias

Just test the code as below:

  $uri = substr(request_uri(), 1, strlen(request_uri()));
  $uri_array = array();
  if(!($path = drupal_lookup_path('source', $uri))) {
    $uri_array = explode('/', $uri);
  }
  else {
    $uri_array = explode('/', $path);
  }

  var_dump($uri_array);

Have fun!