Laravel Validation: Custom Validation Rules

Php artisan make:rule Uppercase

<?php

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class Uppercase implements Rule
{
    /**
     * Determine if the validation rule passes.
     *
     * @param  string  $attribute
     * @param  mixed  $value
     * @return bool
     */
    public function passes($attribute, $value)
    {
        return strtoupper($value) === $value;
    }

    /**
     * Get the validation error message.
     *
     * @return string
     */
    public function message()
    {
        return 'The :attribute must be uppercase.';
    }
}

/**
 * Get the validation error message.
 *
 * @return string
 */
public function message()
{
    return trans('validation.uppercase');
}

Use App\Rules\Uppercase;

$request->validate([
    'name' => ['required', 'string', new Uppercase],
]);

$validator = Validator::make($request->all(), [
    'title' => [
        'required',
        'max:255',
        function ($attribute, $value, $fail) {
            if ($value === 'foo') {
                $fail($attribute.' is invalid.');
            }
        },
    ],
]);

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Support\Facades\Validator;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Validator::extend('foo', function ($attribute, $value, $parameters, $validator) {
            return $value == 'foo';
        });
    }

    /**
     * Register the service provider.
     *
     * @return void
     */
    public function register()
    {
        //
    }
}

Validator::extend('foo', 'FooValidator@validate');