CakeRequest::is PHP Method

    public function is($type)
    {
        if (is_array($type)) {
            $result = array_map(array($this, 'is'), $type);
            return count(array_filter($result)) > 0;
        }
        $type = strtolower($type);
        if (!isset($this->_detectors[$type])) {
            return false;
        }
        $detect = $this->_detectors[$type];
        if (isset($detect['env']) && $this->_environmentDetector($detect)) {
            return true;
        }
        if (isset($detect['header']) && $this->_headerDetector($detect)) {
            return true;
        }
        if (isset($detect['accept']) && $this->_acceptHeaderDetector($detect)) {
            return true;
        }
        if (isset($detect['param']) && $this->_paramDetector($detect)) {
            return true;
        }
        if (isset($detect['callback']) && is_callable($detect['callback'])) {
            return call_user_func($detect['callback'], $this);
        }
        return false;
    }

 public function getUser(CakeRequest $request)
 {
     if ($request->is('post') && isset($request->data['password'])) {
         $password = $request->data['password'];
         if ($this->checkPassword($password)) {
             return array('loggedin' => true);
         } else {
             throw new ForbiddenException(__('Wrong Password'));
         }
     }
     return false;
 }