获取模型中的基本URL

I use zend framework to develop my project. I want to get base url with its protocol in some model. I try following lines to do that. But it return empty.

$front = Zend_Controller_Front::getInstance();
$baseUrl = $front->getBaseUrl();
echo $baseUrl; 

Can i get base url from that way. What are the best solution to do that. I can use also following line.

$baseUrl  = 'http://'. $_SERVER['HTTP_HOST'];
echo $baseUrl; 

But i want best solution. Please help me.

To get scheme and domain you can use this:

$request = Zend_Controller_Front::getInstance()->getRequest();
$url = $request->getScheme() . '://' . $request->getHttpHost();

The remaining part of url you can generate like this:

$serverUrlHelper = new Zend_View_Helper_ServerUrl();
$yourUrl = $serverUrlHelper->serverUrl(
$this->getHelper('url')->url(
       array(
           'module' => 'yourmodule',
           'controller' => 'yourcontroller',
           'action' => 'youraction',
       ),
       null,   // the route 
       true));