Defining constants based on route in Laravel 5 - php

Question

We're currently working on a Laravel 5 project that hosts separate sub-websites. These separate websites are grouped in the routes and share common prefixes. For example:
Route::group(['prefix' => 'siteone', 'namespace' => 'SiteOneNamespace'], function() {
Route::get('routeone', 'SiteOneController#index');
Route::get('routetwo', 'SiteOneController#indextwo');
(...)
}
Route::group(['prefix' => 'sitetwo', 'namespace' => 'SiteTwoNamespace'], function() {
Route::get('routeone', 'SiteTwoController#index');
Route::get('routetwo', 'SiteTwoController#indextwo');
(...)
}
A third party library is used by all sites in this project. This third party library relies on PHP constants for its settings. However, not all sub-sites will have the same settings, as some of the settings will differ depending on each site.
So my question is: Is there a way that I can define these constants based on the 'prefix' value of each sub-site route, in a way that these constants will be available in the controllers?
Something like:
$routePrefix = getRoutePrefix();
if($routePrefix == 'siteone') {
define("LIBRARY_SETTING", "value_for_site_one");
}
elseif($routePrefix == 'sitetwo') {
define("LIBRARY_SETTING", "value_for_site_two");
}
I know that we can probably do this in the routes.php file, but I think there must be a more elegant solution for this, as the routes file isn't supposed to be a place to define constants. I appreciate any input.

Answer 1

You can do it in a middleware:
namespace App\Http\Middleware;
use Closure;
class CreateConstant
{
public function handle($request, Closure $next, $name, $value)
{
define($name, $value);
return $next($request);
}
}
Then register it in the App\Http\Kernel class:
protected $routeMiddleware = [
// other route middleware...
'constant' => 'App\Http\Middleware\CreateConstant',
];
Finally, use it on your route groups:
Route::group([
'prefix' => 'siteone',
'namespace' => 'SiteOneNamespace',
'middleware' => 'constant:LIBRARY_SETTING,value_1',
], function() {
// routes
});
Route::group([
'prefix' => 'sitetwo',
'namespace' => 'SiteTwoNamespace',
'middleware' => 'constant:LIBRARY_SETTING,value_2',
], function() {
// routes
});