--- /dev/null
+<?php
+
+namespace Drupal\media_entity_twitter\Plugin\Validation\Constraint;
+
+use Drupal\media_entity\EmbedCodeValueTrait;
+use Drupal\media_entity_twitter\Plugin\MediaEntity\Type\Twitter;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+
+/**
+ * Validates the TweetEmbedCode constraint.
+ */
+class TweetEmbedCodeConstraintValidator extends ConstraintValidator {
+
+ use EmbedCodeValueTrait;
+
+ /**
+ * {@inheritdoc}
+ */
+ public function validate($value, Constraint $constraint) {
+ $value = $this->getEmbedCode($value);
+ if (!isset($value)) {
+ return;
+ }
+
+ foreach (Twitter::$validationRegexp as $pattern => $key) {
+ if (preg_match($pattern, $value)) {
+ return;
+ }
+ }
+
+ $this->context->addViolation($constraint->message);
+ }
+
+}