Challenge 2: Create a FormRequest — Possible Solution
====================================================================

# php artisan make:request UpdateBookRequest
# FormRequest created successfully.

// app/Http/Requests/UpdateBookRequest.php

namespace App\Http\Requests;

use Illuminate\Foundation\Http\FormRequest;

class UpdateBookRequest extends FormRequest
{
    public function authorize(): bool
    {
        return true;
    }

    public function rules(): array
    {
        return [
            'title' => 'required|string|max:255',
            'price' => 'required|numeric|min:0',
        ];
    }
}

// app/Http/Controllers/BookController.php — BEFORE (inline validation)

public function update(Request $request, Book $book)
{
    $validated = $request->validate([
        'title' => 'required|string|max:255',
        'price' => 'required|numeric|min:0',
    ]);
    $book->update($validated);
    return redirect()->route('books.show', $book);
}

// app/Http/Controllers/BookController.php — AFTER (using the FormRequest)

use App\Http\Requests\UpdateBookRequest;

public function update(UpdateBookRequest $request, Book $book)
{
    $book->update($request->validated());
    return redirect()->route('books.show', $book);
}

WHY THIS WORKS
--------------
- Swapping the parameter type from Illuminate\Http\Request to
  App\Http\Requests\UpdateBookRequest is the entire change needed at the
  controller level — Laravel's service container resolves the type hint,
  automatically runs UpdateBookRequest's rules() against the incoming
  request BEFORE the update() method body executes, and only calls the
  method at all if validation passes.
- Route model binding (Chapter 3) and FormRequest validation compose
  cleanly together in the same method signature — Book $book is resolved
  from the route parameter, UpdateBookRequest $request is resolved and
  validated independently, and both happen before a single line of the
  method body runs.
- Moving rules() into its own class means the same validation rules could
  be reused elsewhere (a different route hitting the same update logic,
  or a test asserting against UpdateBookRequest::rules() directly)
  without duplicating the rule strings — the same "don't repeat this
  logic" motivation behind extracting a dedicated class rather than
  leaving validation inline forever.