Laravel 11 validation requiring a single item in an array has to be one of the following

Question

I am using form request validation and allow for vehicles to be created in the form. Each vehicle has a ref which can be A, B, C, or D. However, in each form request there must always be a single ref: "A". There can be any amount of the others.

I am not in control of the form. The requests come through an API.

My rules array currently contains:

'form.vehicles' => 'required',
'form.vehicles.*.ref' => 'required|in:A,B,C,D

Currently I am using the following code:

if (! in_array('A', $this->input('form.vehicles.*.ref'))) {
  throw new HttpResponseException(response()->json(['MessageString' => 'Vehicle ref A is required'], 422));

This however means the messageBag is unable to be sent in the response for other validation issues.

Answer 1

I used Tim Lewis's suggestion of creating a custom rule implementing ValidationRule:

namespace App\Rules;

use Illuminate\Contracts\Validation\ValidationRule;

class VehicleA implements ValidationRule
{
    /**
     * Run the validation rule.
     *
     * @param  \Closure(string): \Illuminate\Translation\PotentiallyTranslatedString  $fail
     */
    public function validate(string $attribute, mixed $value, Closure $fail): void
    {
        $requiredVehicle = collect($value)->first(function ($vehicle) { 
            return $vehicle['ref'] === 'A';
        });  

        if ($requiredVehicle === null) { 
            $fail('Vehicle A is required'); 
        }
    }

Inside my form request:

'form.vehicles' => [
    'required',
    new VehicleA,
],