How to modify user messages without hacking core user module?

Question

When "themeing" modules, especially core modules, as far as I know it is a good idea to take the module specific tpl.php files, duplicate the ones you need, and modify them once they're in the relevant theme directory.

However, what if I want to modify a .inc file? Is it the same process as with tpl.php files, or is there a better workflow? Basically what I would like to do is change some of the user status messages found in user.admin.inc in the core Drupal 7 User module. I'm not sure if editing this file directly is a good idea. Thoughts?

Answer 1

You can't override an .inc file by copying it to your theme, but you can override most of the function with your template.php; for example, any form can be altered using hook_form_alter(), or any function whose name starts with "theme" can be override by using YOURTHEME_functionaname() in your theme template.php.

Answer 2

Take a look at String Overrides module, which allows to overwrite everything passed through t(). So, it works for “the strings in the module that's already installed”.

There are other ways to alter data in Drupal, but I’m sure in your case overwriting needed.

String Overrides just uses core drupal overwrite behavior, but adds nice UI to control it. Let me point you again to core comments for string overwriting:

First, check for an array of customized strings. If present, use the array instead of database lookups. This is a high performance way to provide a handful of string replacements. See settings.php for examples. Cache the $custom_strings variable to improve performance.

Answer 3

In a comment you said you wanted to replace the string for the error message "The name [username] is not allowed." That error message is returned only from Drupal 6 core, or from a Drupal 7 module; the function that in Drupal 6 shown that error has been removed from Drupal 7, together the functionality of allowing/not allowing some usernames. Drupal 7 can disallow some IPs from being used when accessing a Drupal site.

In Drupal 6, the function showing that error message is user_admin_access_check_submit(), which contains the following code.

  switch ($form_state['values']['type']) {
    case 'user':
      if (drupal_is_denied('user', $form_state['values']['test'])) {
        drupal_set_message(t('The username %name is not allowed.', array('%name' => $form_state['values']['test'])));
      }
      else {
        drupal_set_message(t('The username %name is allowed.', array('%name' => $form_state['values']['test'])));
      }
      break;
      // …
 }

The same message is shown at least from the User restrictions module, which is the third-party module that implements the functionality that has been removed from Drupal 6. I am one of the maintainers of that module, even though I didn't touch its code from months.

To change that message I would implement hook_form_alter() to add a new validation handler that alters the error message, if the error message is shown during the validation of a form, or to add a new form submission handler, if the error message is shown during the submission of a form.

In both the cases:

• The messages set with drupal_set_message() are saved in $_SESSION['messages'][$type], where $type is status, error, or warning. Keep in mind you don't see the string 'The username %name is not allowed.' but the string where %name is already replaced with the username. You would need a regular expression to find that message, and replace it with the string you prefer.

• The error messages set with form_set_error() are returned from $errors = &drupal_static('form_set_error, array());. The array follows the format$error[$field_name] = $error_message`. Also in this case, the string you are looking for contains the username, and you need to user a regular expression to find the error message. You need to alter this array if the error message is set in a form validation handler.

Keep in mind that:

• The error message, in Drupal 6, and the User restrictions module, doesn't mean the username contains spaces when it should not. It means there is a rule that doesn't allow a user to use a specific username; for example, there could be a rule that disallow usernames matching fun%boy (it's a regular expression used from MySQL, and other database engines), and the error message would appear when the username is fun boy, fun-boy, fund boy, or funxxxxxxxboy.

• In Drupal 7, spaces in usernames are allowed; they are not allowed at the beginning of the username, at the end of the username, or when there are 2 or more spaces in row.