src/Web/RequestHelper.php
public function getServerParam($name, $defaultValue = null) {
        return \Reaction\Helpers\ArrayHelper::getValue($this->getServerParams(), $name, $defaultValue);
    }
public function getServerParam($name, $defaultValue = null) {
        return \Reaction\Helpers\ArrayHelper::getValue($this->getServerParams(), $name, $defaultValue);
    }
Get server parameter like from '$_SERVER'
@param string $name
@param mixed  $defaultValue
@return mixed