How to validate 2 Laravel fields in a NAND way - laravel

Question

I'm looking for a solution to the following case: my controller action receives 2 variables, however they must exclude eachother. So you can pass either 1 of them or none.
The following truth table arises (NAND):
| A | B | Result |
|---|---|--------|
| 0 | 0 | 1 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
(say A equals points and B equals coupon).
// MyController.php
$this->validate($request, [
'points' => '',
'coupon' => ''
]);
I've tried some solutions like nullable|required_without:field_name but those seem to result in an XOR, which means you must pass at least 1 of them.

Answer 1

I've decided to create a new rule called without:field1,field2:
Validator::extend('without', function($attribute, $value, $parameters, \Illuminate\Validation\Validator $validator) {
foreach($parameters as $compare) {
// Check if the given parameters are filled in, if so we return `false`.
if($validator->validateRequired(null, array_get($validator->getData(), $compare))) {
return false;
}
}
// No `without` parameters have been found, validation successful.
return true;
});
// Replace the error message placeholders.
Validator::replacer('without', function ($message, $attribute, $rule, $parameters, \Illuminate\Validation\Validator $validator) {
$attributes = [];
foreach ($parameters as $key => $value) {
$attributes[$key] = $validator->getDisplayableAttribute($value);
}
return str_replace(':values', implode(' / ', $attributes), $message);
});
Next, add a translation to resources/lang/en/validation.php:
'without' => 'The :attribute may not be set with :values',
Then you can simply use it like this:
$this->validate($request, [
'points' => 'nullable|without:coupon',
'coupon' => 'nullable|without:points'
]);
(you may add multiple parameters like without:coupon,user_id)
Which makes sure that:
Passing pointsand coupon together results in a validation error
Passing a single one of them is OK
Passing neither of them is OK