Symfony twig path() when using multiple domains - symfony

Question

I have a Symfony project that uses two different domains for two different countries. The site is a client login interface and is basically the same for both domains except for branding and minor name differences. That part is okay.
The two domains are defined in my parameters as us_domain and ca_domain, and in my routing.yml I have:
clients:
resource: #ClientsBundle/Resources/config/routing.yml
host: "clients.{domain}"
prefix: /
requirements:
domain: %us_domain%|%ca_domain%
defaults: { domain: "%us_domain%" }
In Twig, I have my menu using:
<li><span>Home</span></li>
The problem is that although the page will come up on either domain, the paths being generated always use the us_domain, apparently pulling it from defaults in my routing. (I can switch this to ca_domain and the paths do switch).
My question is, why isn't the current domain being detected and used? It seems like the default should be overridden by whatever domain is actually being used?
I'm running Nginx if that matters.

Answer 1

I somehow had missed that the routing variables weren't going to be auto-detected, but you had to pass them as part of your calls. I ended up solving this with a custom Twig filter.
Where I used my path, I passed the domain variable pulling from app.request.host, such as
<li><span>Home</span></li>
And then just wrote Twig extension that parsed/evaluated the host and passed back the domain
<?php
namespace AppBundle\Twig;
use JMS\DiExtraBundle\Annotation as DI;
/**
* Class TwigUrlExtension
* #DI\Service("twig.extension.url")
* #DI\Tag("twig.extension")
*
*/
class TwigUrlExtension extends \Twig_Extension
{
protected $ca_domain;
protected $us_domain;
/**
*
* #DI\InjectParams({
* "us_domain" = #DI\Inject("%us_domain%"),
* "ca_domain" = #DI\Inject("%ca_domain%")
* })
* #param $us_domain
* #param $ca_domain
*/
public function __construct($us_domain, $ca_domain)
{
$this->us_domain = $us_domain;
$this->ca_domain = $ca_domain;
}
/**
* {#inheritdoc}
*/
public function getFunctions() {
return array(
'domainFromHost' => new \Twig_Function_Method($this, 'toDomain')
);
}
/**
* #param string $string
* #return int
*/
public function toDomain ($string) {
if(stripos($string,$this->ca_domain) !== false)
return $this->ca_domain;
if(stripos($string,$this->us_domain) !== false)
return $this->us_domain;
return $string;
}
/**
* {#inheritdoc}
*/
public function getName() {
return 'twig_url_extension';
}
}