Applied API role specs to short URL creation

module/Core/src/Domain/DomainService.php

@@ -8,6 +8,7 @@ use Doctrine\ORM\EntityManagerInterface;
 use Shlinkio\Shlink\Core\Domain\Model\DomainItem;
 use Shlinkio\Shlink\Core\Domain\Repository\DomainRepositoryInterface;
 use Shlinkio\Shlink\Core\Entity\Domain;
+use Shlinkio\Shlink\Core\Exception\DomainNotFoundException;
 use Shlinkio\Shlink\Rest\ApiKey\Role;
 use Shlinkio\Shlink\Rest\Entity\ApiKey;
 
@@ -43,4 +44,15 @@ class DomainService implements DomainServiceInterface
             ...$mappedDomains,
         ];
     }
+
+    public function getDomain(string $domainId): Domain
+    {
+        /** @var Domain|null $domain */
+        $domain = $this->em->find(Domain::class, $domainId);
+        if ($domain === null) {
+            throw DomainNotFoundException::fromId($domainId);
+        }
+
+        return $domain;
+    }
 }