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(PHP 5 >= 5.1.0, PHP 7, PHP 8)
Interface for customized serializing.
Classes that implement this interface no longer support __sleep() and __wakeup(). The serialize() method is called whenever an instance needs to be serialized. This does not invoke __destruct() or have any other side effect unless programmed inside the method. When the data is unserialized the class is known and the appropriate unserialize() method is called as a constructor instead of calling __construct(). The constructor can be called from within the unserialize() method if desired.
As of PHP 8.1.0, a class which implements Serializable without also implementing __serialize() and __unserialize() will generate a deprecation warning.
New code should use the __serialize() and __unserialize() magic methods instead, available as of PHP 7.4.0. When a class declares both them and this interface, serialize() always uses __serialize() and never reaches Serializable::serialize(). Unserializing is decided by the format of the data instead: a payload written by PHP 7.4.0 or later is read by __unserialize(), one written before it is still read by Serializable::unserialize(). Implementing Serializable therefore remains of use for reading such older payloads, and for satisfying a Serializable type declaration; declaring all four methods covers every case, and avoids the deprecation notice.
Зауваження:
The magic methods have no interface of their own, so a class which declares them without implementing Serializable is not an instance of it. method_exists() is the way to detect them.
Приклад #1 Supporting PHP 7.1.0 through 7.3.0
The magic methods carry the serialized form, and the interface methods delegate to them, so that a single representation serves both.
<?php
class Task implements Serializable
{
private $label;
public function __construct($label)
{
$this->label = $label;
}
public function __serialize(): array
{
return ['label' => $this->label];
}
public function __unserialize(array $data): void
{
$this->label = $data['label'];
}
// Never called as of PHP 7.4.0
public function serialize()
{
return serialize($this->__serialize());
}
// Still called as of PHP 7.4.0, for data written before it
public function unserialize($data)
{
$this->__unserialize(unserialize($data));
}
}
var_dump(serialize(new Task('deploy')));
?>Поданий вище приклад виведе:
string(40) "O:4:"Task":1:{s:5:"label";s:6:"deploy";}"
Prior to PHP 7.4.0, the same code serializes through the interface
instead, and outputs
string(47) "C:4:"Task":31:{a:1:{s:5:"label";s:6:"deploy";}}".
