Self validating command (using symfony validator)

Command.php

<?php

abstract class Command
{
    // Self-validating command
    public static function loadValidatorMetadata(ClassMetadata $metadata): void
    {
        $metadata->addConstraint(
            new Callback(function(Command $command, ExecutionContextInterface $context) {
                $reflClass = new \ReflectionClass($command);
                foreach ($reflClass->getProperties(\ReflectionProperty::IS_PUBLIC) as $reflProp) {
                    if (
                        !$reflClass->hasMethod($reflProp->getName())
                        || !$reflClass->getMethod($reflProp->getName())->isPublic()
                    ) {
                        continue;
                    }
                    
                    // Domain will detect invalid data and we will expose those errors to the world
                    try {
                        $command->{$reflProp->getName()}();
                    } catch (\InvalidArgumentException $e) {
                        $context->buildViolation($e->getMessage())
                            ->atPath($reflProp->getName())
                            ->setInvalidValue($command->{$reflProp->getName()})
                            ->addViolation()
                        ;
                    }
                }
            })
        );
    }
}

DoSomething.php

<?php

final class DoSomethingOnFoo extends Command
{
    private string $id;
  
    private string $bar;
    
    public function __construct(string $id, string $bar)
    {
        $this->id = $id;
        $this->bar = $bar;
    }
  
    public function id(): FooId
    {
        return FooId::fromString($this->id);
    }
    
    public function bar(): Bar
    {
        return Bar::fromString($this->bar);
    }
}

example.php

<?php

$command = new DoSomethingOnFoo('123ABC', 'Lorem Ipsum');

$validator = new class implements \Symfony\Component\Validator\Validator\ValidatorInterface
{
    //...
};

$errors = $validator->validate($command);
if (count($errors) > 0) {
    // convert errors to whatever format that suits your need, (eg: json, terminal output, ....)
}

$commandBus->dispatch($command);