php - 在 null 上调用成员函数 isCollection()

Question

我，使用 Graphaware Neo4j-php-OGM。我想访问二级关系。我看不到让它工作。我做错了什么？

我正在尝试执行以下操作:

public function allowToContinue($userUuid, $permissionUuid)
    {
        $userRepo = $this->entityManager->getRepository(User::class);
        $permRoleRepo = $this->entityManager->getRepository(PermRole::class);
        $permissionRepo = $this->entityManager->getRepository(Permission::class);
        $user = $userRepo->findOneBy(['uuid' => $userUuid]);
        $permission = $permissionRepo->findOneBy(['uuid' => $permissionUuid]);
        $allowed = false;
        foreach ($user->getPermrole() as $userRole)
        {
            var_dump($userRole);
            $role = $permRoleRepo->findOneBy(['uuid' => $userRole->getUuid()]);
            var_dump($role);
            foreach ($role->getPermissions() as $perm)
            {
                var_dump($perm->getUuid());
                if($perm->getUuid() === $permissionUuid){
                    $allowed = true;
                }
            }
        }
        return $allowed;
    }

堆栈跟踪:

Error:
Call to a member function isCollection() on null

  at vendor/graphaware/neo4j-php-ogm/src/Hydrator/EntityHydrator.php:107
  at GraphAware\Neo4j\OGM\Hydrator\EntityHydrator->hydrateSimpleRelationshipCollection('permissions', object(Result), object(neo4j_ogm_proxy_App_Entity_Generic_PermRole))
     (vendor/graphaware/neo4j-php-ogm/src/Persisters/BasicEntityPersister.php:104)
  at GraphAware\Neo4j\OGM\Persisters\BasicEntityPersister->getSimpleRelationshipCollection('permissions', object(neo4j_ogm_proxy_App_Entity_Generic_PermRole))
     (vendor/graphaware/neo4j-php-ogm/src/Proxy/NodeCollectionInitializer.php:22)
  at GraphAware\Neo4j\OGM\Proxy\NodeCollectionInitializer->initialize(object(Node), object(neo4j_ogm_proxy_App_Entity_Generic_PermRole))
     (vendor/graphaware/neo4j-php-ogm/src/Proxy/LazyCollection.php:52)
  at GraphAware\Neo4j\OGM\Proxy\LazyCollection->doInitialize()
     (vendor/doctrine/collections/lib/Doctrine/Common/Collections/AbstractLazyCollection.php:332)
  at Doctrine\Common\Collections\AbstractLazyCollection->initialize()
     (vendor/doctrine/collections/lib/Doctrine/Common/Collections/AbstractLazyCollection.php:274)
  at Doctrine\Common\Collections\AbstractLazyCollection->getIterator()
     (src/Security/RoleChecker.php:45)
  at App\Security\RoleChecker->allowToContinue('8d88d920-5ab0-11e8-a371-001c42dff143', 'd93370b0-585d-11e8-a371-001c42dff143')
     (src/Controller/Generic/UserController.php:146)
  at App\Controller\Generic\UserController->destroy('c34f1380-5ab5-11e8-a371-001c42dff143')
     (vendor/symfony/http-kernel/HttpKernel.php:149)
  at Symfony\Component\HttpKernel\HttpKernel->handleRaw(object(Request), 1)
     (vendor/symfony/http-kernel/HttpKernel.php:66)
  at Symfony\Component\HttpKernel\HttpKernel->handle(object(Request), 1, true)
     (vendor/symfony/http-kernel/Kernel.php:188)
  at Symfony\Component\HttpKernel\Kernel->handle(object(Request))
     (public/index.php:37)

它在第 2 个 foreach 循环上抛出错误:

foreach ($role->getPermissions() as $perm)

很奇怪，第一次正常工作，第二次却不行。还要再次获取对象后才能确定。没有这个它会抛出完全相同的通知。提前致谢!

所有代码都在github: https://github.com/djkevino/Support4Neo

Answer 1

老实说，这段代码让我很困惑。 var_dump() die() 中的东西 destroy()...另外，我花了一段时间才意识到我们在谈论库中的代码，而不是你的代码与这个库交互。

你能避免这样的问题吗？

//add this next line
if (!is_iterable($user->getPermrole())) continue;
foreach ($role->getPermissions() as $perm)

如果您使用的不是 PHP 7.1 或更高版本，您可以简单地检查返回值 is_null 或测试 instance of\Traversable 和 is_array...

is_array($foo) || (is_object($foo) && ($foo instanceof \Traversable ));

如我的评论所述，不确定没有“权限”的角色是否被视为有效状态。