email_alter.module

<?php
// $Id$

/**
 * @file
 * Email Alter allows admin interface creation of rulesets which can
 * modify Drupal generated emails.
 */

function email_alter_get_aliases() {
  return variable_get('email_alter_aliases', '');
}

function email_alter_get_aliases_parsed() {
  return email_alter_aliases_parse(
    email_alter_get_aliases());
}

function email_alter_menu() {
  $items = array();

  $items['admin/settings/email-alter'] = array(
    'title' => t('Email Alter Settings'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('email_alter_admin'),
    'access arguments' => array('administer site configuration'),
    'type' => MENU_NORMAL_ITEM,
  );

  return $items;
}

function email_alter_admin() {
  $form = array();

  $form['email_alter_aliases'] = array(
    '#type' => 'textarea',
    '#title' => t('Email Aliases'),
    '#default_value' => email_alter_get_aliases(),
    '#description' => t(
        '<strong>Key-value pairs MUST be specified as '
      . '"alias_email@example.net | email1@foo.com,email2@bar.com"</strong>.'),
    '#rows' => 10,
    '#validate' => array('email_alter_admin_validate'),
  );

  return system_settings_form($form);
}

function email_alter_admin_validate($form_id, &$form) {
  $raw_aliases = $form['values']['email_alter_aliases'];
  $valid = email_alter_aliases_validate($raw_aliases);
  if (!$valid)
    form_set_error('', t('Please correct your Alias declaration syntax.'));
}

function email_alter_email_regex() {
  // Adapting email patterns from Drupal core function, valid_email_address()..
  $user = '[a-zA-Z0-9_\-\.\+\^!#\$%&*+\/\=\?\`\|\{\}~\']+';
  $domain = '(?:(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.?)+';
  $ipv4 = '[0-9]{1,3}(\.[0-9]{1,3}){3}';
  $ipv6 = '[0-9a-fA-F]{1,4}(\:[0-9a-fA-F]{1,4}){7}';
  $email = "$user@($domain|(\[($ipv4|$ipv6)\]))";
  return $email;
}

function email_alter_aliases_validate($raw_aliases) {
  $email = email_alter_email_regex();
  $line =
      '\s*' . $email . '\s*\|\s*'         # Required alias.
    . $email                              # Required real address.
    . '(?:' . '\s*,\s*' . $email . ')*'   # Potential additional reals.
    . '\s*';

  $pattern =
      '/\A'
    . '(?:' . $line . ')*'
    . '\z/ms';

  return preg_match($pattern, $raw_aliases);
}

function email_alter_alias_unparse($alias, $value) {
  return "$alias | $value";
}

function email_alter_aliases_unparse($aliases) {
  return implode("\n",
    array_map('email_alter_alias_unparse', array_keys($aliases), $aliases));
}

function email_alter_aliases_parse($aliases) {
  $alias_lines = explode("\n", $aliases);
  $aliases_parsed = array();

  foreach ($alias_lines as $alias_line) {
    $alias = preg_replace('/\s*\|.*/', '', $alias_line);
    $value = preg_replace('/.*\|\s*/', '', $alias_line);
    $aliases_parsed[$alias] = $value;
  }

  return $aliases_parsed;
}

function email_alter_mail_alter(&$message) {
  $emailkeyvals = email_alter_get_aliases_parsed();

  if ( in_array($message['to'], array_keys($emailkeyvals))) {
    // This code currently supports single address replacement.
    $message['to'] = $emailkeyvals[$message['to']];
  }
}