Object_Freezer

This class provides the low-level functionality required to store ("freeze") PHP objects to and retrieve ("thaw") PHP objects from an object store.

Object_Freezer::freeze()

Freezes an object.

In the example below, we freeze an object of class A. As this object aggregates an object of class B, the object freezer has to freeze two objects in total.

<?php
require_once 'Object/Freezer.php';

class A
{
    protected $b;

    public function __construct()
    {
        $this->b = new B;
    }
}

class B
{
    protected $foo = 'bar';
}

$freezer = new Object_Freezer;
var_dump($freezer->freeze(new A));
?>

Below is the output of the code example above.

array(2) {
  ["root"]=>
  string(36) "32246c35-f47b-4fbc-a2ad-ed14e520865e"
  ["objects"]=>
  array(2) {
    ["32246c35-f47b-4fbc-a2ad-ed14e520865e"]=>
    array(3) {
      ["className"]=>
      string(1) "A"
      ["isDirty"]=>
      bool(true)
      ["state"]=>
      array(2) {
        ["b"]=>
        string(57) "__php_object_freezer_3cd682bf-8eba-4fec-90e2-ebe98aa07ab7"
        ["__php_object_freezer_hash"]=>
        string(40) "8b80da9c38c0c41c829cbbefbca9b18aa67ff607"
      }
    }
    ["3cd682bf-8eba-4fec-90e2-ebe98aa07ab7"]=>
    array(3) {
      ["className"]=>
      string(1) "B"
      ["isDirty"]=>
      bool(true)
      ["state"]=>
      array(2) {
        ["foo"]=>
        string(3) "bar"
        ["__php_object_freezer_hash"]=>
        string(40) "e04e935f09f2d526258d8a16613c5bce31e84e87"
      }
    }
  }
}

If the object has not been frozen before, the attribute __php_object_freezer_uuid will be added to it.

The reference to the object of class B that the object of class A had before it was frozen has been replaced with the UUID of the frozen object of class B (__php_object_freezer_3cd682bf-8eba-4fec-90e2-ebe98aa07ab7).

The result array's root element contains the UUID for the now frozen object of class A (32246c35-f47b-4fbc-a2ad-ed14e520865e).

Object_Freezer::thaw()

Thaws an object.

<?php
require_once 'Object/Freezer.php';

require_once 'A.php';
require_once 'B.php';

$freezer = new Object_Freezer;

var_dump(
  $freezer->thaw(
    array(
      'root'    => '32246c35-f47b-4fbc-a2ad-ed14e520865e',
      'objects' => array(
        '32246c35-f47b-4fbc-a2ad-ed14e520865e' => array(
          'className' => 'A',
          'isDirty'   => FALSE,
          'state'     => array(
            'b' => '__php_object_freezer_3cd682bf-8eba-4fec-90e2-ebe98aa07ab7',
          ),
        ),
        '3cd682bf-8eba-4fec-90e2-ebe98aa07ab7' => array(
          'className' => 'B',
          'isDirty'   => FALSE,
          'state'     => array(
            'foo' => 'bar',
          )
        )
      )
    )
  )
);
?>

Below is the output of the code example above.

object(A)#3 (2) {
  ["b":protected]=>
  object(B)#5 (2) {
    ["foo":protected]=>
    string(3) "bar"
    ["__php_object_freezer_uuid"]=>
    string(36) "3cd682bf-8eba-4fec-90e2-ebe98aa07ab7"
  }
  ["__php_object_freezer_uuid"]=>
  string(36) "32246c35-f47b-4fbc-a2ad-ed14e520865e"
}

Object_Freezer_Storage_CouchDB

This class provides the means to use CouchDB as an object storage.

<?php
require_once 'Object/Freezer/Storage/CouchDB.php';

class A
{
    protected $b;

    public function __construct()
    {
        $this->b = new B;
    }
}

class B
{
    protected $foo = 'bar';
}

$storage = new Object_Freezer_Storage_CouchDB(
  'database', NULL, NULL, TRUE, 'localhost', 5984
);

$id = $storage->store(new A);

var_dump($storage->fetch($id));
?>

Below is the output of the code example above.

object(A)#3 (2) {
  ["b":protected]=>
  object(B)#5 (2) {
    ["foo":protected]=>
    string(3) "bar"
    ["__php_object_freezer_uuid"]=>
    string(36) "3cd682bf-8eba-4fec-90e2-ebe98aa07ab7"
  }
  ["__php_object_freezer_uuid"]=>
  string(36) "32246c35-f47b-4fbc-a2ad-ed14e520865e"
}