How to logically compare values (numbers) field values in CakePHP 3 validation

Question

I'm trying to use the comparison rule but seems am missing something or not doing it right. Basically what I need is validation to check that the value of small_size is less or equal to big_size.

But this isn't working, am currently getting the error regardless of the sizes.

In the Table:

     ...
     $validator
        ->add('small_size', 'valid', ['rule' => 'numeric'])
        ->requirePresence('small_size', 'create')
        ->notEmpty('small_size')
        ->add('small_size', 'comparison', [
            'rule' => ['comparison', 'big_size', '<='],
            'message' => 'Small size cannot be more than the Big size.'
        ]);
    return $validator;
}

public function buildRules(RulesChecker $rules)
{
    $rules->add($rules->existsIn(['Entity_id'], 'Entity'));
    return $rules;
}

Some help on this will be much appreciated.

Answer 1

You cannot use the built-in comparison rule to compare two fields, you need to use a custom rule:

$validator->add('small_size', 'comparison', [
    'rule' => function ($value, $context) {
        return intval($value) <= intval($context['data']['big_size']) ;
    },
    'message' => 'Small size cannot be bigger than Big size.'
]);