Streamlining Route Parameters in Laravel Using URL Defaults

Managing URL parameters in Laravel applications, particularly those with multiple languages or complex routing patterns, can become repetitive. Laravel provides an elegant solution through URL defaults, allowing you to set application-wide default values for URL parameters. Let's explore this powerful feature's implementation.

Understanding URL Defaults

URL defaults enable you to define global default values for URL parameters across your application. This proves particularly valuable for handling common parameters like language preferences or regional settings.

Let's implement URL defaults in a multilingual application with currency support:

<?php
 
namespace App\Http\Middleware;
 
use Closure;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\URL;
 
class SetUrlDefaults
{
    public function handle(Request $request, Closure $next)
    {
        URL::defaults([
            'locale' => $request->user()?->preferred_language ?? config('app.locale'),
            'currency' => $request->user()?->preferred_currency ?? 'USD'
        ]);
        return $next($request);
    }
}

<?php
 
namespace App\Http;
 
class Kernel extends HttpKernel
{
    protected $middleware = [
        // ... other middleware
        \App\Http\Middleware\SetUrlDefaults::class,
    ];
}

Implementing the routing structure:

<?php
 
use App\Http\Controllers\ProductController;
 
Route::prefix('{locale}/{currency}')->group(function () {
    Route::get('products', [ProductController::class, 'index'])
        ->name('products.index');
 
    Route::get('products/{product}', [ProductController::class, 'show'])
        ->name('products.show');
});
 
class ProductController extends Controller
{
    public function index()
    {
        // URLs will automatically use default locale and currency
        return view('products.index', [
            'products' => Product::paginate(20),
            'categoryUrl' => route('products.category', ['category' => 'electronics'])
        ]);
    }
 
    public function changePreferences(Request $request, $locale, $currency)
    {
        $request->user()->update([
            'preferred_language' => $locale,
            'preferred_currency' => $currency
        ]);
 
        return redirect()->back();
    }
}

In your views, you can generate URLs without explicitly specifying the defaults:

<!-- Products listing view -->
<nav>
    <a href="{{ route('products.index') }}">{{ __('All Products') }}</a>
    <a href="{{ route('products.show', $product) }}">{{ $product->name }}</a>
</nav>
 
<!-- Only override when needed -->
<a href="{{ route('products.index', ['currency' => 'EUR']) }}">
    {{ __('View in Euros') }}
</a>