<?php
// $Id: globalredirect.module,v 1.1.2.4.2.10 2008/07/08 11:09:18 njt1982 Exp $
/**
 * @file
 * The Global Redirect module redirects for all paths which have aliases but are not using the aliases which reduces the risk of duplicate content
 */
/**
 * Implementation of hook_help().
 */
function globalredirect_help($section) {
  switch ($section) {
    case 'admin/modules#description':
      return t('This module will do a 301 redirect for all nodes which have an alias but are not using that alias.');
  }
}


/**
 * Implementation of hook_init().
 */
function globalredirect_init() {
  //We need to do a test to make sure we only clean up URL's for the main request. This stops modules such as
  //  the Ad Module which had its own script in its folder doing a bootstrap which invoked hook_init and caused some banners to get "cleaned up"
  //  See issue: http://drupal.org/node/205810
  if ($_SERVER['SCRIPT_NAME'] != '/index.php') return false;

  /**
   * We need to make sure this hook only fires in certain conditions:
   *   1) If the 'drupal_get_path' function exists. Sometimes hook_init gets called twice, the first call hasn't included path.inc.
   *   2) If the callback associated with the request is accessible - this stops the user learning hidden/private url aliases.
   *   3) If there is a request. There is no point checking the REAL frontpage for an alias.
   *   4) If the $_POST is empty. The problem which arises here is if a form posts to an source path rather than the alias. GlobalRedirect sometimes interrupts the post and redirects to the alias instead.
   */

  if (function_exists('drupal_get_path_alias') &&
      _menu_item_is_accessible(menu_get_active_item()) &&
      isset($_REQUEST['q']) &&
      empty($_POST)) {

    //Store the destination from the $_REQUEST as it breaks things if we leave it in - restore it at the end...
    if (isset($_REQUEST['destination'])) {
      $destination = $_REQUEST['destination'];
      unset($_REQUEST['destination']);
    }

    // Get the Query String (minus the 'q'). If none set, set to NULL
    $query_string = drupal_query_string_encode($_GET, array('q'));
    if (empty($query_string)) {
      $query_string = NULL;
    }

    // If current path is also the frontpage, redirect to http://www.example.com.
    if (!empty($_REQUEST['q']) && drupal_is_front_page()) {
      drupal_goto('', $query_string, NULL, 301);
    }

    // Trim any trailing slash off the end (eg, 'node/1/' to 'node/1')
    $request = trim($_REQUEST['q'], '/');

    // Check the path (eg, node/123) for an request.
    $alias = drupal_get_path_alias($request);

    // If alias is different to the request, redirect...
    if ($alias != $request) {
      drupal_goto($alias, $query_string, NULL, 301);
    }

    // If the trimmed request differs to the request then redirect (basically, de-slash the source path)
    if ($request != $_REQUEST['q']) {
      drupal_goto($request, $query_string, NULL, 301);
    }

    //If no alias was returned, the final check is to direct non-clean to clean - if clean is enabled.
    if ((bool)variable_get('clean_url', 0) && strpos(request_uri(), '?q=')) {
      drupal_goto($request, $query_string, NULL, 301);
    }

    //Restore the destination from earlier so its available in other places.
    if (isset($destination)) $_REQUEST['destination'] = $destination;
  }
}