ConstraintAttributeInterface

Raxos\Contract\Http\Validate\ConstraintAttributeInterface is an extension point for raxos/http. Implement it, usually as a PHP attribute, to write a custom validation constraint that checks a request property beyond the built in constraints.

Signature

interface ConstraintAttributeInterface extends AttributeInterface
{
    public function check(ReflectionProperty $property, mixed $value): mixed;
}

The interface is templated (@template TValue of mixed).

Methods

check(ReflectionProperty $property, mixed $value): mixed

Validates $value, the incoming value for $property. Returns the value, potentially transformed, or throws a ConstraintExceptionInterface when it is invalid.

Notes

• It extends the empty marker AttributeInterface, shared with other Http validate attributes.
• Implementations are attached directly to a request model property, next to #[Property] and the built in constraints described in raxos/http's validation docs.
• A single class can implement both ConstraintAttributeInterface and TransformerInterface when a value needs both checking and reshaping, for example turning a loosely typed array into a strongly typed collection.
• This is a typical extension point: raxos/http calls into it, your application supplies the implementation. See extension points.

Example

<?php
declare(strict_types=1);

namespace App\Http\Constraint;

use Attribute;
use Override;
use Raxos\Contract\Http\Validate\ConstraintAttributeInterface;
use Raxos\Http\Validate\Error\ConstraintErrorException;
use ReflectionProperty;

#[Attribute(Attribute::TARGET_PROPERTY)]
final readonly class IsHexColor implements ConstraintAttributeInterface
{
    #[Override]
    public function check(ReflectionProperty $property, mixed $value): string
    {
        if (!is_string($value) || !preg_match('/^#[0-9a-f]{6}$/i', $value)) {
            throw new ConstraintErrorException('is_hex_color', 'Expected a hex color such as #ff0000.');
        }

        return $value;
    }
}