Implementing Wakeup or Clone¶
Section author: Roman Borschel (roman@code-factory.org)
As explained in the restrictions for entity classes in the manual, it is usually not allowed for an entity to implement __wakeup or __clone, because Doctrine makes special use of them. However, it is quite easy to make use of these methods in a safe way by guarding the custom wakeup or clone code with an entity identity check, as demonstrated in the following sections.
Safely implementing __wakeup¶
To safely implement __wakeup, simply enclose your implementation code in an identity check as follows:
<?php
class MyEntity
{
private $id; // This is the identifier of the entity.
//...
public function __wakeup()
{
// If the entity has an identity, proceed as normal.
if ($this->id) {
// ... Your code here as normal ...
}
// otherwise do nothing, do NOT throw an exception!
}
//...
}
Safely implementing __clone¶
Safely implementing __clone is pretty much the same:
<?php
class MyEntity
{
private $id; // This is the identifier of the entity.
//...
public function __clone()
{
// If the entity has an identity, proceed as normal.
if ($this->id) {
// ... Your code here as normal ...
}
// otherwise do nothing, do NOT throw an exception!
}
//...
}
Summary¶
As you have seen, it is quite easy to safely make use of __wakeup and __clone in your entities without adding any really Doctrine-specific or Doctrine-dependant code.
These implementations are possible and safe because when Doctrine invokes these methods, the entities never have an identity (yet). Furthermore, it is possibly a good idea to check for the identity in your code anyway, since it’s rarely the case that you want to unserialize or clone an entity with no identity.