Created rest endpoint to list existing domains

module/Core/src/Domain/DomainService.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Core\Domain;
+
+use Doctrine\ORM\EntityManagerInterface;
+use Shlinkio\Shlink\Core\Domain\Repository\DomainRepositoryInterface;
+use Shlinkio\Shlink\Core\Entity\Domain;
+
+class DomainService implements DomainServiceInterface
+{
+    private EntityManagerInterface $em;
+
+    public function __construct(EntityManagerInterface $em)
+    {
+        $this->em = $em;
+    }
+
+    /**
+     * @return Domain[]
+     */
+    public function listDomainsWithout(?string $excludeDomain = null): array
+    {
+        /** @var DomainRepositoryInterface $repo */
+        $repo = $this->em->getRepository(Domain::class);
+        return $repo->findDomainsWithout($excludeDomain);
+    }
+}

module/Core/src/Domain/DomainServiceInterface.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Core\Domain;
+
+use Shlinkio\Shlink\Core\Entity\Domain;
+
+interface DomainServiceInterface
+{
+    /**
+     * @return Domain[]
+     */
+    public function listDomainsWithout(?string $excludeDomain = null): array;
+}

module/Core/src/Domain/Repository/DomainRepository.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Core\Domain\Repository;
+
+use Doctrine\ORM\EntityRepository;
+use Shlinkio\Shlink\Core\Entity\Domain;
+
+class DomainRepository extends EntityRepository implements DomainRepositoryInterface
+{
+    /**
+     * @return Domain[]
+     */
+    public function findDomainsWithout(?string $excludedAuthority = null): array
+    {
+        $qb = $this->createQueryBuilder('d')->orderBy('d.authority', 'ASC');
+
+        if ($excludedAuthority !== null) {
+            $qb->where($qb->expr()->neq('d.authority', ':excludedAuthority'))
+               ->setParameter('excludedAuthority', $excludedAuthority);
+        }
+
+        return $qb->getQuery()->getResult();
+    }
+}

module/Core/src/Domain/Repository/DomainRepositoryInterface.php

@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Core\Domain\Repository;
+
+use Doctrine\Persistence\ObjectRepository;
+use Shlinkio\Shlink\Core\Entity\Domain;
+
+interface DomainRepositoryInterface extends ObjectRepository
+{
+    /**
+     * @return Domain[]
+     */
+    public function findDomainsWithout(?string $excludedAuthority = null): array;
+}