How to add a default parameter for all routes in laravel

I have a multi lingual website. where i want to add current locale as prefix for all of my project routes. For that to be than any time i use a route i must always provide a value for locale parameter of the route. I think there are better ways of doing this.

My routes looks like this

Route::prefix('{locale}')->group(function() {
    Route::get('/', [App\Http\Controllers\HomeController::class, 'index'])->name('home');
    Route::get('/blog', [App\Http\Controllers\PostController::class, 'index'])->name('blog');
});

I want my path in url looks like this.

• http://localhost/project/en/blog or
• http://localhost/project/fa/blog

I also have a middleware SetLocale where I decide app locale according to the request path coming through;

here is my middleware code

class SetLocale
{
    public function handle(Request $request, Closure $next)
    {

        $locale = $request->segment(1);
        if (! is_null($locale) && ! in_array($locale, config('app.locales')) ) // config('app.locales') = ['en', 'ar', 'fa']
            abort(404);

        $html_dir = in_array($locale, ['en'])?'ltr':'rtl';
        \Illuminate\Support\Facades\Config::set('app.html_dir', $html_dir);
        \Illuminate\Support\Facades\App::setLocale($locale);


        return $next($request);
    }
}

You can use the defaults method of the URL Generator do this exact thing:

URL::defaults(['locale' => $locale]);

Add that in your middleware and the locale parameter will have a default when generating a URL to routes using that parameter.

Laravel 8.x Docs - URL Generation - Default Values defaults