spl_classes
It is possible to mark objects with unique identity to establish required functionality:
<?php
if (!function_exists('spl_object_hash')) {
function spl_object_hash($object) {
if (!is_object($object)) {
trigger_error(__FUNCTION__ . "() expects parameter 1 to be object", E_USER_WARNING);
return null;
}
if (!isset($object->__oid__))
$object->__oid__ = uniqid();
}
return $object->__oid__;
}
}
?>
spl_object_hash
(PHP 5 >= 5.2.0)
spl_object_hash — Retourne l'identifiant de hashage pour un objet donné
Description
string spl_object_hash
( object $obj
)
Cette fonction retourne un identifiant unique pour l'objet. Cet identifiant peut être utilisé comme clé de hashage pour stocker les objets ou pour les identifier.
Liste de paramètres
- object
-
N'importe quel objet.
Valeurs de retour
Retourne une chaîne de caractères, unique pour chaque objet et qui est toujours la même pour le même objet.
Exemples
Exemple #1 Exemple avec spl_object_hash()
<?php
$id = spl_object_hash($object);
$storage[$id] = $object;
?>
add a note
User Contributed Notesspl_object_hash
test user
14-Oct-2009 12:15
14-Oct-2009 12:15
SlappyTheFish
28-May-2009 10:12
28-May-2009 10:12
With regards to the previous post, I'm not entirely sure that easy does do it. Consider the following code:
<?php
class Testy
{
public $something;
public function __toString()
{
return serialize($this);
}
}
$objOne = new Testy();
$objOne->something = "hello";
$objTwo = new Testy();
$objTwo->something = "hello";
printf("objOne:\n");
printf("Bad way: %s\n", md5((string)$objOne));
printf("SPL Way: %s\n", spl_object_hash($objOne));
printf("objTwo:\n");
printf("Bad way: %s\n", md5((string)$objTwo));
printf("SPL Way: %s\n", spl_object_hash($objTwo));
?>
The spl_object_hash function returns a hash based on the particular object, not the content. The spl hash will always be the same for a given object, regardless of content.
andi.rein(AT)gmx de
15-Apr-2009 11:48
15-Apr-2009 11:48
Easy does it
<?php
if (!function_exists('spl_object_hash')) {
/**
* Returns the hash of the unique identifier for the object.
*
* @param object $object
* @author Andreas Rein
* @return string
*/
function spl_object_hash($object) {
if (is_object($object)) {
return md5((string)$object);
}
trigger_error(__FUNCTION__ . "() expects parameter 1 to be object", E_USER_WARNING);
return null;
}
}
?>
Rafael M. Salvioni
04-Dec-2008 07:01
04-Dec-2008 07:01
The follow function is a implementation of the PHP´s function spl_object_hash(), unavailable in versions less 5.2.0.
But, the algorithm of this function is different of the original PHP´s function.
(Sorry... my english is very bad...)
<?php
if (!function_exists('spl_object_hash')) {
/**
* Returns the hash of the unique identifier for the object.
*
* @param object $object Object
* @author Rafael M. Salvioni
* @return string
*/
function spl_object_hash($object)
{
if (is_object($object)) {
ob_start(); var_dump($object); $dump = ob_get_contents(); ob_end_clean();
if (preg_match('/^object\(([a-z0-9_]+)\)\#(\d)+/i', $dump, $match)) {
return md5($match[1] . $match[2]);
}
}
trigger_error(__FUNCTION__ . "() expects parameter 1 to be object", E_USER_WARNING);
return null;
}
}
?>
planetbeing
05-Jul-2007 11:40
05-Jul-2007 11:40
Note that the contents (properties) of the object are NOT hashed by the function, merely its internal handle and handler table pointer. This is sufficient to guarantee that any two objects simultaneously co-residing in memory will have different hashes. Uniqueness is not guaranteed between objects that did not reside in memory simultaneously, for example:
var_dump(spl_object_hash(new stdClass()), spl_object_hash(new stdClass()));
Running this alone will usually generate the same hashes, since PHP reuses the internal handle for the first stdClass after it has been dereferenced and destroyed when it creates the second stdClass.