framework/web/UrlManager.php
public function getHostInfo()
    {
        if ($this->_hostInfo === null) {
            $request = Yii::$app->getRequest();
            if ($request instanceof \yii\web\Request) {
                $this->_hostInfo = $request->getHostInfo();
            } else {
                throw new InvalidConfigException('Please configure UrlManager::hostInfo correctly as you are running a console application.');
            }
        }

        return $this->_hostInfo;
    }
public function getHostInfo()
    {
        if ($this->_hostInfo === null) {
            $request = Yii::$app->getRequest();
            if ($request instanceof \yii\web\Request) {
                $this->_hostInfo = $request->getHostInfo();
            } else {
                throw new InvalidConfigException('Please configure UrlManager::hostInfo correctly as you are running a console application.');
            }
        }

        return $this->_hostInfo;
    }
Returns the host info that is used by [[createAbsoluteUrl()]] to prepend to created URLs.
@return string the host info (e.g. `http://www.example.com`) that is used by [[createAbsoluteUrl()]] to prepend to created URLs.
@throws InvalidConfigException if running in console application and [[hostInfo]] is not configured.