trampoline.module

<?php
/**
 * @file
 * Trampoline module to facilitate AJAX callbacks without a full Drupal bootstrap.
 */

/**
 * Implementation of hook_form_FORM_ID_alter().
 *
 * Add a reset button to the performance page.
 */
function trampoline_form_system_performance_settings_alter(&$form, $form_state) {
  $form['trampoline'] = array(
    '#type' => 'fieldset',
    '#title' => t('Trampoline AJAX booster'),
    '#description' => t("Trampoline allows modules to invoke AJAX callbacks without requiring a full Drupal bootstrap for the callback."),
  );

  $form['trampoline']['trampoline_flush'] = array(
    '#type' => 'submit',
    '#value' => t('Rebuild trampoline file'),
    '#submit' => array('trampoline_admin_flush_caches'),
  );

  $form['clear_cache']['#weight'] = 5;
  $form['buttons']['#weight'] = 10;

}

/**
 * Submit handler for the Trampoline rebuild button.
 *
 * @see trampoline_form_system_performance_settings_alter().
 */
function trampoline_admin_flush_caches(&$form, $form_state) {
  trampoline_flush_caches();
  drupal_set_message(t('Trampoline file will be rebuild on next use.'));
}

/**
 * Implements hook_init()
 */
function trampoline_init() {
  drupal_add_js(array('trampolinePath' => base_path() . drupal_get_path('module', 'trampoline') . '/index.php?q='), 'setting');
  trampoline_build();
}

/**
 * Implementation of hook_flush_caches().
 */
function trampoline_flush_caches() {
  // Delete the config file
  module_load_include('inc', 'trampoline', 'trampoline');
  file_delete(trampoline_files_path() . '/trampoline.config.inc');
  trampoline_build();
}

/**
 * Build config file for callback script.
 */
function trampoline_build() {
  global $language;
  global $theme_key;
  global $base_url;
  $profile = variable_get('install_profile', 'default');
  
  // Require common.inc to make drupal_get_path() available.
  // hook_exit may be invoked without a full bootstrap and we need
  // this function to generate paths properly.
  require_once './includes/common.inc';
  module_load_include('inc', 'trampoline', 'trampoline');
  $config_file = trampoline_files_path() . '/trampoline.config.inc';

  // Only build the configuration files once.  Clear the cache to rebuild it,
  // or use the button on admin/settings/performance.
  if (!file_exists($config_file)) {
    if (!file_check_directory(trampoline_files_path(), FILE_CREATE_DIRECTORY)) {
      watchdog('trampoline', 'Config file @config is not writable.', array('@config' => $config_file), WATCHDOG_ERROR);
      return;
    }
    $trampoline_config = array();

    //Build base configuration
    $trampoline_config['language'] = $language->language;
    $trampoline_config['profile'] = $profile;
    $trampoline_config['theme_path'] = drupal_get_path('theme', $theme_key);
    $trampoline_config['theme_settings'] = theme_get_settings();
    $trampoline_config['base_path'] = base_path();
    $trampoline_config['base_url'] = $base_url;

    //Build route configuration
    $trampoline_routes = array();

    $routes = module_invoke_all('trampoline');
    // We need these basic structures to build the trampoline config
    while (!lock_acquire('menu_rebuild')) {
      lock_wait('menu_rebuild');
    }
    $menu_router = menu_router_build();
    lock_release('menu_rebuild');
    // NB: The theme registry is only available from this function if it has been build previously.
    $theme_registry = theme_get_registry();


    foreach (module_invoke_all('trampoline_variables') as $variable) {
      $trampoline_config['variables'][$variable] = variable_get($variable, NULL);
    }

    foreach ($routes as $route => $config) {
      if (isset($menu_router[$route])) {
        $menu_route = $menu_router[$route];
        //Build the route configuration
        $route_config = array();

        $route_config['module'] = $menu_route['module'];
        $route_config['module_path'] = drupal_get_path('module', $menu_route['module']);

        //Get the files to load
        $module_path = drupal_get_path('module', $menu_route['module']);

        $route_config['includes'] = array($module_path .'/'.$menu_route['module'].'.module');
        if (isset($config['includes'])) {
          $route_config['includes'] = array_merge($route_config['includes'], $config['includes']);
        }
        if ($menu_route['file']) {
          $route_config['includes'][] = $module_path.'/'.$menu_route['file'];
        }

        //Get the callback
        $route_config['callback'] = $menu_route['page callback'];

        //Get the arguments
        $route_config['arguments'] = $menu_route['page arguments'];

        $route_config['variables'] = array();
        $route_config['variables']['clean_url'] = variable_get('clean_url', '0');
        if (isset($config['theme_hooks'])) {
          //Get theme information
          $route_config['theme'] = array();
          foreach ($config['theme_hooks'] as $theme_hook) {
            $route_config['theme'][$theme_hook] = $theme_registry[$theme_hook];
          }
        }


        if (is_array($config['hooks'])) {
          foreach ($config['hooks'] as $hook => $name) {
            if (is_array($name)) {
              $implementations = module_implements($hook);
              foreach ($implementations as $i) {
                if (in_array($i, $name)) {
                  $trampoline_config['hooks'][$hook] = $i;
                }
              }
            }
            else {
              $implementations = module_implements($name);
              $trampoline_config['hooks'][$name] = $implementations;
            }
          }
        }
      }
      $trampoline_routes[$route] = $route_config;
    }

    $trampoline_config['routes'] = $trampoline_routes;

    // Write the configuration to a file
    // TODO: This is a nasty security hole. PHP files writeable by
    // the web server, ouch.
    file_put_contents($config_file, '<?php $trampoline_config = ' . var_export($trampoline_config, true) . ';');
  }
}

/**
 * Utility function for generation the url to a path using trampoline.
 * Arguments duplicate the original url function.
 *
 * @see url
 */
function trampoline_url($path = NULL, $options = array()) {
  // Store the original path in the q argument
  $defaults = array('query' => 'q='.$path);
  $options = array_merge($defaults, $options);
  return url(drupal_get_path('module', 'trampoline').'/index.php', $options);
}