(PHP 3>= 3.0.5, PHP 4 )

unserialize --  Creates a PHP value from a stored representation


mixed unserialize ( string str)

unserialize() takes a single serialized variable (see serialize()) and converts it back into a PHP value. The converted value is returned, and can be an integer, float, string, array or object.

Note: It's possible to set a callback-function which will be called, if an undefined class should be instanciated during unserializing. (to prevent getting an incomplete object "__PHP_Incomplete_Class".) Use your php.ini, ini_set() or .htaccess-file to define 'unserialize_callback_func'. Everytime an undefined class should be instanciated, it'll be called. To disable this feature just empty this setting.

Example 1. unserialize_callback_func example


ini_set('unserialize_callback_func','mycallback'); // set your callback_function

function mycallback($classname) {
    // just include a file containing your classdefinition
    // you get $classname to figure out which classdefinition is required

Note: In PHP 3, methods are not preserved when unserializing a serialized object. PHP 4 removes that limitation and restores both properties and methods. Please see the Serializing Objects section of Classes and Objects or more information.

Example 2. unserialize() example

// Here, we use unserialize() to load session data to the
// $session_data array from the string selected from a database.
// This example complements the one described with serialize().

$conn = odbc_connect ("webdb", "php", "chicken");
$stmt = odbc_prepare ($conn, "SELECT data FROM sessions WHERE id = ?");
$sqldata = array ($PHP_AUTH_USER);
if (!odbc_execute ($stmt, &$sqldata) || !odbc_fetch_into ($stmt, &$tmp)) {
    // if the execute or fetch fails, initialize to empty array
    $session_data = array();
} else {
    // we should now have the serialized data in $tmp[0].
    $session_data = unserialize ($tmp[0]);
    if (!is_array ($session_data)) {
        // something went wrong, initialize to empty array
        $session_data = array();

See Also: serialize().