如何在 Symfony 中设置数据转换器以重用现有实体? [英] How to setup a data transformer in Symfony to reuse existing entities?
问题描述
我正在 Symfony 中开发一个带有内置标记功能的文章编辑器:
控制器
class MainController 扩展控制器{公共函数 indexAction(Request $request, $id){$em = $this->getDoctrine()->getManager();//$article = ...$form = $this->createForm(new ArticleType(), $article);$form->handleRequest($request);如果 ($form->isValid()) {$em->persist($article);$em->flush();返回 $this->redirect($this->generateUrl('acme_edit_success'));}return $this->render('AcmeBundle:Main:index.html.twig', array('形式' =>$form->createView()));}}表格
标签表单被注册为带有 @Doctrine 参数的服务，所以我可以在类中使用实体管理器.标签表单嵌入在文章表单中.
文章类型.php
class ArticleType 扩展 AbstractType{公共函数 buildForm(FormBuilderInterface $builder, array $options){$builder->添加('内容')->add('tags', 'collection', array('类型' =>'acme_bundle_tagtype','allow_add' =>真的，'allow_delete' =>真的，'by_reference' =>错误的))->add('保存', '提交');}公共函数 setDefaultOptions(OptionsResolverInterface $resolver){$resolver->setDefaults(array('data_class' =>'AcmeBundleEntityArticle','cascade_validation' =>真的));}公共函数 getName(){返回acme_bundle_articletype"；}}TagType.php
class TagType 扩展 AbstractType{私人 $entityManager;公共函数 buildForm(FormBuilderInterface $builder, array $options){$transformer = new TagTransformer($this->entityManager);$builder->add($builder->create('name')->addModelTransformer($transformer));}函数 __construct(DoctrineBundleDoctrineBundleRegistry $doctrine) {$this->entityManager = $doctrine->getManager();}公共函数 setDefaultOptions(OptionsResolverInterface $resolver){$resolver->setDefaults(array('data_class' =>'AcmeBundleEntityTag'));}公共函数 getName(){返回acme_bundle_tagtype"；}}数据转换器
我创建了这个数据转换器来检查给定的标签是否已经存在，然后将标签对象转换为数据库中已经存在的对象:
class TagTransformer 实现 DataTransformerInterface{/*** @var 对象管理器*/私人 $om;/*** @param ObjectManager $om*/公共函数 __construct(ObjectManager $om){$this->om = $om;}公共函数转换($tag){if (null === $tag) {返回 '';}返回 $tag;}公共函数 reverseTransform($name){如果(！$名称)返回空；$tag = $this->om->getRepository('AcmeBundle:Tag')->findOneByName($name);如果(！$标签){$tag = 新标签();$tag->setName($name);}返回 $tag;}}当我尝试使用已经存在的标签保存文章时，reverseTransform() 函数成功返回原始标签对象，但 DBAL 通过其将对象转换回字符串__toString() 方法，Doctrine 仍然启动一个 INSERT 查询而不是 UPDATE，所以我得到下一个错误:<块引用>
执行'INSERT INTO Tag (name) 时发生异常VALUES (?)' 带参数 [{}]:
SQLSTATE[23000]:违反完整性约束:1062 重复条目键UNIQ_0123456789ABCDE"的现有标签"
我该如何解决这个问题?当我输入一个已经在使用的标签名称时，我希望 Symfony 在文章-标签关系中使用相同的标签.实体类出现在我之前关于如何避免与 Doctrine 的多对多关系中的重复条目 的问题中.
你的转换器有一个错误.您应该验证是否返回了标签，而不是检查 name 是否为 null:
if (!$tag) {$tag = 新标签();$tag->setName($name);}你也不需要持久化标签，因为默认情况下学说会级联持久化所有相关实体.
完整方法:
public function reverseTransform($name){如果(！$名称){返回空；}$tag = $this->om->getRepository('AcmeBundle:Tag')->findOneByName($name);如果(！$标签){$tag = 新标签();$tag->setName($name);}返回 $tag;}I'm working on an article editor in Symfony with built-in tagging capability:
The controller
class MainController extends Controller
{
public function indexAction(Request $request, $id)
{
$em = $this->getDoctrine()->getManager();
// $article = ...
$form = $this->createForm(new ArticleType(), $article);
$form->handleRequest($request);
if ($form->isValid()) {
$em->persist($article);
$em->flush();
return $this->redirect($this->generateUrl('acme_edit_success'));
}
return $this->render('AcmeBundle:Main:index.html.twig', array(
'form' => $form->createView()
));
}
}
The forms
The tag form is registered as a service with the @Doctrine argument, so I can use the entity manager inside the class. The tag form is embed inside the article form.
ArticleType.php
class ArticleType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('content')
->add('tags', 'collection', array(
'type' => 'acme_bundle_tagtype',
'allow_add' => true,
'allow_delete' => true,
'by_reference' => false
))
->add('save', 'submit')
;
}
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$resolver->setDefaults(array(
'data_class' => 'AcmeBundleEntityArticle',
'cascade_validation' => true
));
}
public function getName()
{
return 'acme_bundle_articletype';
}
}
TagType.php
class TagType extends AbstractType
{
private $entityManager;
public function buildForm(FormBuilderInterface $builder, array $options)
{
$transformer = new TagTransformer($this->entityManager);
$builder->add(
$builder->create('name')
->addModelTransformer($transformer)
);
}
function __construct(DoctrineBundleDoctrineBundleRegistry $doctrine) {
$this->entityManager = $doctrine->getManager();
}
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$resolver->setDefaults(array(
'data_class' => 'AcmeBundleEntityTag'
));
}
public function getName()
{
return 'acme_bundle_tagtype';
}
}
The data transformer
I created this data transformer to check if the given tag already exists and then transform the tag object to the one that already exists in the database:
class TagTransformer implements DataTransformerInterface
{
/**
* @var ObjectManager
*/
private $om;
/**
* @param ObjectManager $om
*/
public function __construct(ObjectManager $om)
{
$this->om = $om;
}
public function transform($tag)
{
if (null === $tag) {
return '';
}
return $tag;
}
public function reverseTransform($name)
{
if (!$name)
return null;
$tag = $this->om
->getRepository('AcmeBundle:Tag')
->findOneByName($name)
;
if (!$tag) {
$tag = new Tag();
$tag->setName($name);
}
return $tag;
}
}
When I try to save an article with an already existing tag, the reverseTransform() function successfully returns the original tag objects, but the DBAL converts the object back to a string by its __toString() method, and Doctrine still initiates an INSERT query instead of UPDATE, so I get the next error:
An exception occurred while executing 'INSERT INTO Tag (name) VALUES (?)' with params [{}]:
SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'An Existing Tag' for key 'UNIQ_0123456789ABCDE'
How can I fix this? When I enter a tag name that's already in use, I want Symfony to use the same tag in the article-tag relationship. The entity classes appear in my previous question about how to avoid duplicate entries in a many-to-many relationship with Doctrine.
There's one mistake in your transformer. Instead of checking if name is null you should verify if a tag was returned:
if (!$tag) {
$tag = new Tag();
$tag->setName($name);
}
You also don't need to persist the tag since by default doctrine will cascade persist all the related entities.
Full method:
public function reverseTransform($name)
{
if (!$name) {
return null;
}
$tag = $this->om
->getRepository('AcmeBundle:Tag')
->findOneByName($name)
;
if (!$tag) {
$tag = new Tag();
$tag->setName($name);
}
return $tag;
}
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