file/app/Http/Requests/FileUpdateRequest.php

<?php

namespace App\Http\Requests;

use Illuminate\Foundation\Http\FormRequest;

class FileUpdateRequest extends FormRequest
{
    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return true;
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array<string, mixed>
     */
    public function rules()
    {
        return [
            "alts" => [app()->collection->alt_required ? "required" : "nullable", 'array'],
            "alts.*" => [app()->collection->alt_required ? "required" : "nullable", 'max:1000'],
            "description" => [app()->collection->description_required ? "required" : "nullable", 'max:300'],
            'original_name' => ["string", "nullable", 'max:300'],
            'published_at' => ['date_format:Y-m-d H:i:s', 'nullable'],
        ];
    }
}