laravel request ensure that value is NULL not NULLABLE

To ensure that a specific field in a Laravel request is NULL, you can use a custom validation rule. Laravel does not have a built-in null validation rule, but you can create a custom rule to achieve this.

Here's how you can do it:

1. Create a Custom Validation Rule:

First, you need to create a custom validation rule. You can do this using the make:rule Artisan command:

php artisan make:rule NullValue

This will create a new rule class in the app/Rules directory. Open the newly created NullValue class and modify it as follows:

<?php

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

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

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

2. Use the Custom Rule in Your Request Validation:

Next, you need to use this custom rule in your request validation. Assuming you are using a Form Request for validation, you can do it like this:

use App\Rules\NullValue;

public function rules()
{
    return [
        'area.*.id' => ['required', new NullValue],
    ];
}

If you are not using a Form Request, you can apply the rule directly in your controller:

use App\Rules\NullValue;
use Illuminate\Http\Request;

public function store(Request $request)
{
    $request->validate([
        'area.*.id' => ['required', new NullValue],
    ]);

    // Your logic here
}

This custom rule will ensure that the area.*.id field must be NULL and will return an error message if it is not.

3. Testing the Validation:

You can now test your validation by sending a request where area.*.id is NULL. If the value is not NULL, the validation will fail, and the custom error message will be displayed.

This approach ensures that the area.*.id field is strictly NULL and not just nullable.