SERIALIZE(3) 1 SERIALIZE(3)
serialize - Generates a storable representation of a value
SYNOPSIS
string serialize (mixed $value)
DESCRIPTION
Generates a storable representation of a value.
This is useful for storing or passing PHP values around without losing their type and structure.
To make the serialized string into a PHP value again, use unserialize(3).
PARAMETERS
o $value
- The value to be serialized. serialize(3) handles all types, except the resource-type. You can even serialize(3) arrays that con-
tain references to itself. Circular references inside the array/object you are serializing will also be stored. Any other refer-
ence will be lost. When serializing objects, PHP will attempt to call the member function __sleep() prior to serialization. This
is to allow the object to do any last minute clean-up, etc. prior to being serialized. Likewise, when the object is restored using
unserialize(3) the __wakeup() member function is called.
Note
Object's private members have the class name prepended to the member name; protected members have a '*' prepended to the
member name. These prepended values have null bytes on either side.
RETURN VALUES
Returns a string containing a byte-stream representation of $value that can be stored anywhere.
Note that this is a binary string which may include null bytes, and needs to be stored and handled as such. For example, serialize(3) out-
put should generally be stored in a BLOB field in a database, rather than a CHAR or TEXT field.
EXAMPLES
Example #1
serialize(3) example
<?php
// $session_data contains a multi-dimensional array with session
// information for the current user. We use serialize() to store
// it in a database at the end of the request.
$conn = odbc_connect("webdb", "php", "chicken");
$stmt = odbc_prepare($conn,
"UPDATE sessions SET data = ? WHERE id = ?");
$sqldata = array (serialize($session_data), $_SERVER['PHP_AUTH_USER']);
if (!odbc_execute($stmt, $sqldata)) {
$stmt = odbc_prepare($conn,
"INSERT INTO sessions (id, data) VALUES(?, ?)");
if (!odbc_execute($stmt, $sqldata)) {
/* Something went wrong.. */
}
}
?>
NOTES
Note
Note that many built-in PHP objects cannot be serialized. However, those with this ability either implement the Serializable inter-
face or the magic __sleep() and __wakeup() methods. If an internal class does not fulfill any of those requirements, it cannot reli-
ably be serialized.
There are some historical exceptions to the above rule, where some internal objects could be serialized without implementing the
interface or exposing the methods. Notably, the ArrayObject prior to PHP 5.2.0.
Warning
When serialize(3) serializes objects, the leading backslash is not included in the class name of namespaced classes for maximum
compatibility.
SEE ALSO
unserialize(3), var_export(3), json_encode(3), Serializing Objects, __sleep(), __wakeup().
PHP Documentation Group SERIALIZE(3)