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unserialize

(3.0.5 - 3.0.18 only, PHP 4 >= 4.0.0)

unserialize --  Creates a PHP value from a stored representation

Description

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. If an object was serialized, its methods are not preserved in the returned value.

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 global variable.

Example 1. unserialize_callback_func example

$serialized_object='O:1:"a":1:{s:5:"value";s:3:"100";}';

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 from a database
// into $session_data.    This example complements the one described
// with <function>serialize</function>.

$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().

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