---
title: "Custom Rules"
description: "Creating Custom Rules"
type: "docs"
category: "doc"
tags: []
authors: [Anonymous]
date: "2026-09-09"
last_update: "2026-09-09"
time_minutes: 1
draft: false
unlisted: false
url: "https://www.derafu.dev/docs/data/data-processor/custom-rules"
---

# Creating Custom Rules

## Custom Cast Rule

```php
use Derafu\DataProcessor\Contract\CasterRuleInterface;

final class CustomCastRule implements CasterRuleInterface
{
    public function cast(mixed $value, array $parameters = []): mixed
    {
        // Your casting logic here.
    }
}

// Register the rule.
$registry->addCasterRule('custom_cast', CustomCastRule::class);
```

## Custom Transform Rule

```php
use Derafu\DataProcessor\Contract\TransformerRuleInterface;

final class CustomTransformRule implements TransformerRuleInterface
{
    public function transform(mixed $value, array $parameters = []): mixed
    {
        // Your transformation logic here.
    }
}

// Register the rule.
$registry->addTransformerRule('custom_transform', CustomTransformRule::class);
```

## Custom Sanitizer Rule

```php
use Derafu\DataProcessor\Contract\SanitizerRuleInterface;

final class CustomSanitizerRule implements SanitizerRuleInterface
{
    public function sanitize(mixed $value, array $parameters = []): mixed
    {
        // Your sanitization logic here.
    }
}

// Register the rule.
$registry->addSanitizerRule('custom_sanitize', CustomSanitizerRule::class);
```

## Custom Validator Rule

```php
use Derafu\DataProcessor\Contract\ValidatorRuleInterface;

final class CustomValidatorRule implements ValidatorRuleInterface
{
    public function validate(mixed $value, array $parameters = []): void
    {
        // Your validation logic here.
    }
}

// Register the rule.
$registry->addValidatorRule('custom_validate', CustomValidatorRule::class);
```

## Using Custom Rules

Once registered, you can use your custom rules just like built-in ones:

```php
$processor->process('field', $value, [
    'cast' => 'custom_cast',
    'transform' => ['custom_transform'],
    'sanitize' => ['custom_sanitize'],
    'validate' => ['custom_validate'],
]);
```



---
Last updated on 09/09/2026