Laravel - Is it possible to use a validation rule on a group of attributes?

Question

I'm using Laravel rules and I want to make a validation which requires multiple attributes. For example, I want a rule to check that the quantity requested doesn't exceed the available stock for the given product. So, something like

public function rule() {
  return [
    'quantity produyctId' => "checkQty"
}

I would prefer to solve it using rules but other methods are also acceptable.

Answer 1

You can create a custom validation from extending the validation.

In AppServiceProvider class

Validator::extend('quantity_validity', function ($attribute, $value, $parameters, $validator) {

    $productId = $parameters[0];
    $quantity = $value;

    // you can do whatever with these,
    // and finally return true or false according to your desire.
});

In Validation

public function rule() {
    return [
        'quantity' => "quantity_validity:{$productId}"
    ]
}