How to override the message of the custom validation rule in Laravel? - laravel

Question

I am developing a Laravel application. What I am doing in my application is that I am trying to override the custom validation rule message.
I have validation rules like this in the request class:
[
'name'=> [ 'required' ],
'age' => [ 'required', new OverAge() ],
];
Normally, we override the error message of the rules like this:
return [
'title.required' => 'A title is required',
'body.required' => 'A message is required',
];
But how can I do that to the custom validation rule class?

Answer 1

You cannot simply overwrite it with the custom messages of the request. If you take a look at the Validator class:
/**
* Validate an attribute using a custom rule object.
*
* #param string $attribute
* #param mixed $value
* #param \Illuminate\Contracts\Validation\Rule $rule
* #return void
*/
protected function validateUsingCustomRule($attribute, $value, $rule)
{
if (! $rule->passes($attribute, $value)) {
$this->failedRules[$attribute][get_class($rule)] = [];
$this->messages->add($attribute, $this->makeReplacements(
$rule->message(), $attribute, get_class($rule), []
));
}
}
As you can see, it's simply adding the $rule->message() directly to the message bag.
However, you can add a parameter for the message in your custom rule's class:
public function __construct(string $message = null)
{
$this->message = $message;
}
Then in your message function:
public function message()
{
return $this->message ?: 'Default message';
}
And finally in your rules:
'age' => ['required', new OverAge('Overwritten message')];

Answer 2

Working with Laravel 9, overriding the message is supported, but you must supply the FQDN for the validation class. So your OverAge custom message may look like this:
return [
'age.required' => 'An age is required',
'age.App\\Rules\\OverAge' => 'The age must be less than 65',
];
You may also want to support place-holders for the message, so the 65 can be replaced by something like :max-age. Many ways to do that are published, none of which look particularly clean.