Serializing objects - objects in sessions

Serializing objects - objects in sessions

returns a string containing a

byte-stream representation of any value that can be stored in PHP. can use this string to recreate the original variable values. Using serialize to save an object will save all variables in an object. The methods in an object will not be saved, only the name of the class. serialize``unserialize

In order to be able to an object, the class of that object needs to be defined. That is, if you have an object of class A and serialize this, you'll get a string that refers to class A and contains all values of variables contained in it. If you want to be able to unserialize this in another file, an object of class A, the definition of class A must be present in that file first. This can be done for example by storing the class definition of class A in an include file and including this file or making use of the function. unserialize``spl_autoload_register

<?php
// A.php:
  
  class A {
      public $one = 1;
    
      public function show_one() {
          echo $this->one;
      }
  }
  
// page1.php:

  include "A.php";
  
  $a = new A;
  $s = serialize($a);
  // store $s somewhere where page2.php can find it.
  file_put_contents('store', $s);

// page2.php:
  
  // this is needed for the unserialize to work properly.
  include "A.php";

  $s = file_get_contents('store');
  $a = unserialize($s);

  // now use the function show_one() of the $a object.  
  $a->show_one();
?>

It is strongly recommended that if an application serializes objects, for use later in the application, that the application includes the class definition for that object throughout the application. Not doing so might result in an object being unserialized without a class definition, which will result in PHP giving the object a class of , which has no methods and would render the object useless. __PHP_Incomplete_Class_Name

So if in the example above became part of a session by adding a new key to the superglobal array, you should include the file on all of your pages, not only and . $a``$_SESSION``A.php

Beyond the above advice, note that you can also hook into the serialization and unserialization events on an object using the and methods. Using also allows you to only serialize a subset of the object's properties. __sleep()__wakeup()__sleep()