问题
I would like to handle a single object property on serialization and deserialization with JMSSerializer. Suposing we have this class :
class Task {
const STATUS_PENDING = 0;
const STATUS_OVER = 1;
protected $status;
/* getter and setter */
public function getStatusLabel()
{
return ['pending', 'over'][$this->getStatus()];
}
public static function getStatusFromLabel($label)
{
return [
'pending' => self::STATUS_PENDING,
'over' => self::STATUS_OVER
][$label];
}
}
I would like to return instances of Task threw a REST API (using FOSRestBundle). The problem is that I don't want to return the raw value of the $status
attribute, but the "label" value.
Configuring my serialization like this :
Task:
exclusion_policy: ALL
properties:
status:
expose: true
type: string
The JMS Serializer considers the raw value which is 0 or 1, but I want to send 'pending' or 'over' in my serialized object (using getStatusLabel
). And do the reverse job on deserialization (using getStatusFromLabel
).
I thaught about a virtual_properties
but it works only in serilization direction.
I tried with a custom handler looking like this :
class TaskHandler implements SubscribingHandlerInterface
{
public static function getSubscribingMethods()
{
return [
[
'direction' => GraphNavigator::DIRECTION_SERIALIZATION,
'format' => 'json',
'type' => 'Task',
'method' => 'serializeToArray',
]
];
}
public function serializeToArray(JsonSerializationVisitor $visitor, Task $task, array $type, Context $context)
{
$task->setStatus($task->getStatusLabel());
return $visitor->getNavigator()->accept($task, $type, $context);
}
But it obviously doesn't work !
How could I call my custom getters in both serilization and deserialization directions ?
回答1:
I finally found the answer.
First I had to create an event subsciber like this :
use JMS\Serializer\EventDispatcher\EventSubscriberInterface;
use JMS\Serializer\EventDispatcher\Events;
use JMS\Serializer\EventDispatcher\PreDeserializeEvent;
use JMS\Serializer\EventDispatcher\PreSerializeEvent;
class TaskSubscriber implements EventSubscriberInterface
{
public static function getSubscribedEvents()
{
return [
[
'event' => Events::PRE_SERIALIZE,
'format' => 'json',
'class' => 'Task', // fully qualified name here
'method' => 'onPreSerializeTaskJson',
],
[
'event' => Events::PRE_DESERIALIZE,
'format' => 'json',
'class' => 'Task',
'method' => 'onPreDeserializeTaskJson',
]
];
}
public function onPreSerializeTaskJson(PreSerializeEvent $event)
{
/** @var Task $task */
$task = $event->getObject();
$task->setStatus($task->getStatusLabel());
}
public function onPreDeserializeTaskJson(PreDeserializeEvent $event)
{
$data = $event->getData();
$data['status'] = Task::getStatusFromLabel($data['status']);
$event->setData($data);
}
}
What I'm doing here :
- Before serialization, I set the status value of my Task object with the label
- Before deserialization, I change the value of the serialized object from the label to the raw integer value
For this solution, field has to be exposed (expose: true
or @Expose
) to the serializer.
Then I declared the subscriber as a service in Symfony with the tag jms_serializer.event_subscriber
.
serializer.subscriber.task:
class: %serializer.subscriber.task.class% # TaskSubscriber class path
tags:
- { name: jms_serializer.event_subscriber }
And it works.
It's the best way I found to both serialize and deserialize. It's also possible to manipulate data on post_serialize and post_deserialize events. For example, add a new field on a serialized object :
use JMS\Serializer\EventDispatcher\ObjectEvent;
public function onPostSerializeTaskJson(ObjectEvent $event)
{
/** @var Task $task */
$task = $event->getObject();
$event->getVisitor()->addData('nb_related', count($task->getRelatedTasks()));
}
来源:https://stackoverflow.com/questions/20687489/format-input-and-output-fields-with-jmsserializer-handle-single-property