Laravel Validation - Array fields, only one of two allowed but neither is required

Question

I'm using Laravel Form Request Validation to validate an array of objects, within each object we have two keys neverExpires and numberOfBillingCycles . Neither of these two keys are required, but if both have a value validation should fail as I only want to accept one or the other.

"addOns": {
    "add": [
        {
            "inheritedFromId": "EMEX1",
            "neverExpires": "false",
            "numberOfBillingCycles": "10"   
        },
        {
            "inheritedFromId": "EX1",
            "neverExpires": "true"
        },
        {
            "inheritedFromId": "EX2"
        }
    ]
},

So, in the first instance, because both neverExpires and numberOfBillingCycles have values it should fail validation. The second and third instances should pass as it only contains neverExpires or doesn't contain either.

I've tried creating a custom validator and passing in the two fields as parameters eg. addOns.add.*.neverExpires and addOns.add.*.numberOfBillingCycles but the problem is the parameter index is not set and I can't seem to find the array index within the custom rule to enable me to check the right array object values.

Hope this makes sense? Cheers in advance.

Answer 1

As long as you're using >= Laravel 5.5 you could validate the each item in the add array rather than the individual attributes:

public function rules()
{
    return [
        'addOns.add.*' => [
            function ($attr, $value, $fail) {
                if (array_has($value, ['inheritedFromId', 'numberOfBillingCycles'])) {
                    $fail('You can not have both');
                }
            },
        ],
    ];
}