How to pass parameters in Laravel Rule?

Question

I would like to move this code to the App\Rule:

//Currently in class AppServiceProvider extends ServiceProvider

Validator::extend('empty_if', function ($attribute, $value, $parameters, $validator) {
   return ($value != '' && request($parameters[0]) != '') ? false : true;
});

So that it should be this:

//in: App\Rules\EmptyIf

public function passes($attribute, $value, $parameters)
{
   return ($value != '' && request($parameters[0]) != '') ? false : true;
}

But my problem is, that I cannot pass $parameters with

Validator::extend('empty_if', 'App\Rules\EmptyIf@passes');

How would you pass parameters to Laravel Rule?

Answer 1

Here is a simpler and updated way of accomplishing this, without extending the validator. You can access the passed param in the Rule's constructor, so just set a globally scoped variable and now you can reference it inside of the passes() method. You could even use the same approach to have the value in the validator message.

The validate call:

case 'measurement':
 $request->validate([
   'updates.*.value' => [
   new Measurement('foo-bar'),
   ],
 ]);
 break;

The Rule:

<?php

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class Measurement implements Rule
{
/**
 * Create a new rule instance.
 *
 * @param $param
 */
public function __construct($param)
{
    $this->type = $param;
}

public $type;
/**
 * Determine if the validation rule passes.
 *
 * @param string $attribute
 * @param mixed $value
 * @param array $parameters
 * @return bool
 */
public function passes($attribute, $value)
{
    dd($this->type, 'params');
    return;
}

Answer 2

You can pass parameters with constructor in Rule

public function __construct($params)
{
    $this->params = $params;
}

Then access parameters in passes method

public function passes($attribute, $value)
{
  //access params with $this->params
}