A simple Laravel 4 validator that ensure the field under validation must match the format defined according to the `Carbon\Carbon::createFromFormat` method.

CustomValidator.php

<?php

use Carbon\Carbon;
use Illuminate\Validation\Validator;

class CustomValidator extends Validator {

    # carbon_date_format #

    public function validateCarbonDateFormat($attribute, $value, $parameters)
    {
        try {
            Carbon::createFromFormat($parameters[0], $value);
            return true;
        } catch (Exception $e) {
            return false;
        }
    }

    protected function replaceCarbonDateFormat($message, $attribute, $rule, $parameters)
    {
        return str_replace(':format', $parameters[0], $message);
    }
    
}