How to set _locale dynamically based on host - symfony

Question

Is there any way to set _locale parameter of routing configuration as a function call or an expression result? I have multiple hosts running on the same symfony app, and there is an i18n turned on. Everything is working fine, but now i need to have another locales set for a specified host.
Right now my routing config looks like
app:
resource: '#AppBundle/Controller/'
...
requirements:
_locale: '%route_locales%'
...
and i have something like this in parameters:
...
route_locales: en|de|fr
...
That would be perfect if i can use something like
"#=service('AppBundle\\\\...\\\\LocalesConfigurator').getLocales()"
as a _locale: value to get this value based on a function call result. Or maybe there are some other options to get another _locale set for a specified host?

Answer 1

You can do it like #Jakumi suggested (via env params passed from server)
or using only application logic:
In route_locales put all possible locales that can be used in any host.
Validate incoming _locale inside "request listener" depending on request host - if some _locale is not allowed for host then return 404 response or show 404 error page etc.

Answer 2

Seems like i've found at least one solutuin, thanks to Jakumi for the idea. I've created a parameter in my config file, which receives an environment varaible. Then i use this parameter in my routing file. The main idea is that i can control this environment variable value using bootstrap file. So it looks like
bootstrap.php (in the example it's just a static value, but in a real life this value will depend on host).
bootstrap.php
...
$_SERVER['SYMFONY__ROUTE__LOCALES'] = 'en|es';
...
config.yml
parameters:
route_locales: '%route.locales%'
routing.yml
app:
resource: '#AppBundle/Controller/'
...
requirements:
_locale: '%route_locales%'
...
I don't realy like this solution, and will be thankful for any better solutions, but at least it does what i want.

Answer 3

I was in the same issue some months ago and I was able to found a solution that worked correctly, but there may also be some better ones.
As I needed different route names to be loaded depending on the locale (i.e. /contact in English and /contacto in Spanish) what I did was creating the methods in the controller and creating an individual link to them in routes.yaml
contact-en:
path: /contact/
controller: App\Controller\ContactController::index
host: domain1.tld
contact-es:
path: /contacto/
controller: App\Controller\ContactController::index
host: domain2.tld
Then I created an EventListener called LocaleSwitcher:
class LocaleSwitcher
{
public function onKernelRequest(GetResponseEvent $event)
{
$request = $event->getRequest();
$host = $request->getHost();
switch($host) {
case 'domain1.tld': {
$request->setLocale('en');
break;
}
case 'domain2.tld': {
$request->setLocale('es');
break;
}
}
}
}
And then adding it in services.yaml for event kernel.request and priority 20:
App\EventListener\LocaleSwitcher:
tags:
- { name: kernel.event_listener, event: kernel.request, priority: 20 }