Part #3: Rule objects based custom validation in Laravel

Laravel comes with multiple ways to add custom validation rules to validate form request inputs. I have already explained some of the ways in the following article links:

1. #1: Closure-based Laravel Validation. 

2. #2: How to use Laravel's Validator::extend method for custom validation

In this video, I will show you how you can create custom validation using Rule objects. 

Rule objects are classes that implement the Illuminate\Contracts\Validation\Rule interface. This class contains two methods: passes and message. The passes method gets the attribute value and name, and it should return true or false relying upon regardless of whether the attribute value is valid or not. The message method should return the validation error message which is used when validation fails.

To generate a new rule class, you may use the make:rule Artisan command.

php artisan make:rule MatchCurrentPassword

It will generate a MatchCurrentPassword rule object in the app/Rules directory.

Here’s what a typical custom validation rule class looks like:

<?php

namespace App\Rules;

use App\Models\User;
use Illuminate\Contracts\Validation\Rule;
use Illuminate\Support\Facades\Hash;

class MatchCurrentPassword implements Rule
{
    /**
     * Create a new rule instance.
     *
     * @return void
     */
    public function __construct(User $user)
    {
        $this->user = $user;
    }

    /**
     * Determine if the validation rule passes.
     *
     * @param  string  $attribute
     * @param  mixed  $value
     * @return bool
     */
    public function passes($attribute, $value)
    {
        return Hash::check($value, $this->user->password);
    }

    /**
     * Get the validation error message.
     *
     * @return string
     */
    public function message()
    {
        return 'The current password is invalid.';
    }
}

When the Rule class has been defined, you may attach it to a validator by passing an instance of the rule object with your other validation rules like so.

use App\Rules\MatchCurrentPassword;

$request->validate([
    'current_password' => [
        'required',
        new MatchCurrentPassword($user)
    ],
]);

That is how you can implement your own custom rule objects that validate form requests as per your requirements.