Laravel: How to create correct routes group for localization?

Question

Now I write sample routes without grouping for localization my Laravel project :

Route::get('/{lang?}', function($lang=null){
    App::setlocale($lang);
    return view('welcome');
});

How I can create group of routes correctly for more one language with prefix or with argument instead of prefix or with domain routing in Laravel 5.6? And can be created localization in prefix and domain routing examples:

http://website.com/en
http://en.website.com

Answer 1

Well here's my best try:

Keep all your route definitions in e.g. web.php

You can then use multi-domain routing in your RouteServiceProvider:

Route::group([ 
    'domain' => '{lang}.example.com'
    'middleware' => LangMiddleware::class,
    'namespace' => $this->namespace // I guess?
], function ($router) {
     require base_path('routes/web.php');
});

In addition, using the same routes you can also do prefixed route groups:

Route::group([
        'middleware' => LangMiddleware::class,
        'namespace' => $this->namespace,
        'prefix' => {lang} //Note: This works but is undocumented so may change
], function ($router) {
    require base_path('routes/stateless.php');
});

This all relies on that LangMiddleware middleware class which can be something like:

class LangMiddleware {
     public function handle($request, $next) {
          if ($request->route("lang")) {
               // also check if language is supported?
              App::setlocale($request->route("lang"));
          }
          return $next($request);          
     }         
}