gistfile1.php

<?php

public function likeAction()
  {
    // Make sure user exists
    if( !$this->_helper->requireUser()->isValid() ) return;

    // Collect params
    $action_id = $this->_getParam('action_id');
    $viewer = $this->_helper->api()->user()->getViewer();

    // Start transaction
    $db = $this->_helper->api()->getDbtable('likes', 'activity')->getAdapter();
    $db->beginTransaction();

    try
    {
      $action = $this->_helper->api()->getDbtable('actions', 'activity')->getActionById($action_id);

      // Check authorization
      if (!Engine_Api::_()->authorization()->isAllowed($action->getObject(), null, 'comment'))
        throw new Engine_Exception('This user is not allowed to like this item');

      $action->likes()->addLike($viewer);
        
      // Add notification for owner of activity (if user and not viewer)
      if( $action->subject_type == 'user' && $action->subject_id != $viewer->getIdentity() )
      {
        $actionOwner = Engine_Api::_()->getItemByGuid($action->subject_type."_".$action->subject_id);
        
        Engine_Api::_()->getDbtable('notifications', 'activity')->addNotification($actionOwner, $viewer, $action, 'liked', array(
          'label' => 'post'
        ));
      }
      
      $db->commit();
    }

    catch( Exception $e )
    {
      $db->rollBack();
      throw $e;
    }

    // Success
    $this->view->status = true;
    $this->view->message = Zend_Registry::get('Zend_Translate')->_('You now like this action.');

    // Redirect if not json context
    if( null === $this->_helper->contextSwitch->getCurrentContext() )
    {
      $this->_helper->redirector->gotoRoute(array(), 'core_home');

    }
    else if ('json'===$this->_helper->contextSwitch->getCurrentContext())
    {
      $this->view->body = $this->view->activity($action, array('noList' => true));
    }
  }