system/handlers/ajaxhandler.php

<?php
namespace Habari;

class AjaxHandler extends ActionHandler
{

  public function act_ajax()
  {
    Plugins::act( 'ajax_' . $this->handler_vars['context'], $this );

    // if this is the locale context, serve the locale javascript
    if ( $this->handler_vars['context'] == 'locale' ) {
      $this->locale_js();
    }
  }

  public function act_auth_ajax()
  {
    $user = User::identify();
    if ( $user->loggedin ) {
      Plugins::act( 'auth_ajax_verify',  $this );
      Plugins::act( 'auth_ajax_' . $this->handler_vars['context'], $this );
      exit;
    }
  }

  public function locale_js() {
    header('Expires: ' . gmdate('D, d M Y H:i:s ', time() + 432000) . 'GMT');
    header('content-type: text/javascript');

    $domain = Locale::get_messages();
    $domain_json = json_encode($domain);

    $js = <<<TEEHEE
function _t() {
    var domain = {$domain_json};
    var s = arguments[0];

    if(domain[s] != undefined) {
        s = domain[s][1][0];
    }

    for(var i = 1; i <= arguments.length; i++) {
        r = new RegExp('%' + (i) + '\\\\\$s', 'g');
        if(!s.match(r)) {
            r = new RegExp('%s');
        }
        s = s.replace(r, arguments[i]);
    }
    return s;
}
TEEHEE;
    echo Plugins::filter('locale_js', $js);
  }

  public static function register_ajax($name, $fn)
  {
    Plugins::register($fn, 'action', 'ajax_' . $name);
  }

  public static function register_auth_ajax($name, $fn)
  {
    Plugins::register($fn, 'action', 'auth_ajax_' . $name);
  }


  public static function __static()
  {
    /*
     * These registration functions are here rather than the classes that directly provide
     * their data (like Tags for tag_list or Posts for post_list) because putting them in
     * their respective classes would require that they be autoloaded on every page load
     * so that these functions could register their ajax endpoints.
     */
    // Registers an auth_ajax endpoint for tag autocompletion
    self::register_auth_ajax('tag_list', function(){
      $tags = Tags::search($_GET['q']);
      $results = array();
      foreach($tags as $tag) {
        $results[] = array('id' => $tag->term_display, 'text' => $tag->term_display);
      }
      $ar = new AjaxResponse();
      $ar->data = array(
        'results' => $results,
        'more' => false,
        'context' => array()
      );
      $ar->out();
    });

    // Registers an auth_ajax endpoint for post autocompletion
    self::register_auth_ajax('post_list', function(){
      $posts = Posts::get(array('title_search' => $_GET['q']));
      $results = array();
      foreach($posts as $post) {
        $results[] = array('id' => $post->id, 'text' => $post->title);
      }
      $ar = new AjaxResponse();
      $ar->data = array(
        'results' => $results,
        'more' => false,
        'context' => array()
      );
      $ar->out();
    });

  }

}

?>