Validate field depending on its value url symfony - symfony

Question

I would like to know if you can validate a field depending on its value from a form in Symfony?
For example, I have an url and a name within a form associated to it. If the value of the name is 'instagram' let's say, I want that the url to be validated by the class Instagram Validator and so on. I wrote a switch but I get the error:
Call to a member function buildViolation() on null
What I've tried:
public function validateURL($url, $name)
{
$message = '';
switch ($name) {
case "Instagram":
$instagramValidator = new InstagramValidator();
$instagramValidator->validate($url, new Url());
break;
default:
return;
}
return $message;
}
InstagramValidator:
class InstagramValidator extends ConstraintValidator
{
/**
* {#inheritdoc}
*/
public function validate($url, Constraint $constraint)
{
if (!preg_match('/(?:http:\/\/)?(?:www\.)?instagram\.com\/(?:(?:\w)*#!\/)?(?:pages\/)?(?:[\w\-]*\/)*([\w\-]*)/', $url)) {
$this->context->buildViolation($constraint->message)
->setParameter('{{ value }}', $this->formatValue($url))
->addViolation();
}
}
}
So there is a way to handle this?

Answer 1

You've got this error because you didn't pass $context to validator's constructor.
Create your own constraint and use it via Validation::createValidator()->validate():
use Symfony\Component\Validator\Constraints\Regex;
class Instagram extends Regex
{
public function __construct()
{
parent::__construct(['pattern' => '/your regex/']);
}
public function validatedBy(): string
{
return Regex::class . 'Validator';
}
}
Now you can use it:
$violations = Validation::createValidator()->validate($url, new Instagram());
Also, you can use your own validator, you just have to set it in validatedBy function of your constraint.