Programmer's Reference Guide
| Introduction |
Basic Usage
Zend_Session_Namespace instances provide the primary API for manipulating session data in the Zend
Framework. Namespaces are used to segregate all session data, although a default namespace exists for those who
only want one namespace for all their session data. Zend_Session utilizes ext/session and its
special $_SESSION superglobal as the storage mechanism for session state data. While
$_SESSION is still available in PHP's global namespace, developers should refrain from directly
accessing it, so that Zend_Session and Zend_Session_Namespace can most effectively and
securely provide its suite of session related functionality.
Each instance of Zend_Session_Namespace corresponds to an entry of the $_SESSION
superglobal array, where the namespace is used as the key.
$myNamespace = new Zend_Session_Namespace('myNamespace');
// $myNamespace corresponds to $_SESSION['myNamespace']
$_SESSION directly. To
avoid problems, however, it is highly recommended that such code only uses parts of $_SESSION that
do not correspond to instances of Zend_Session_Namespace.
Tutorial Examples
If no namespace is specified when instantiating Zend_Session_Namespace, all data will be
transparently stored in a namespace called "Default". Zend_Session is not intended
to work directly on the contents of session namespace containers. Instead, we use
Zend_Session_Namespace. The example below demonstrates use of this default namespace, showing
how to count the number of client requests during a session:
Example #1 Counting Page Views
$defaultNamespace = new Zend_Session_Namespace('Default');
if (isset($defaultNamespace->numberOfPageRequests)) {
// this will increment for each page load.
$defaultNamespace->numberOfPageRequests++;
} else {
$defaultNamespace->numberOfPageRequests = 1; // first time
}
echo "Page requests this session: ",
$defaultNamespace->numberOfPageRequests;
When multiple modules use instances of Zend_Session_Namespace having different namespaces, each
module obtains data encapsulation for its session data. The Zend_Session_Namespace constructor
can be passed an optional $namespace argument, which allows developers to partition session
data into separate namespaces. Namespacing provides an effective and popular way to secure session state
data against changes due to accidental naming collisions.
Namespace names are restricted to character sequences represented as non-empty PHP strings that do not begin
with an underscore ("_") character. Only core components included in Zend Framework should
use namespace names starting with "Zend".
Example #2 New Way: Namespaces Avoid Collisions
// in the Zend_Auth component
$authNamespace = new Zend_Session_Namespace('Zend_Auth');
$authNamespace->user = "myusername";
// in a web services component
$webServiceNamespace = new Zend_Session_Namespace('Some_Web_Service');
$webServiceNamespace->user = "mywebusername";
The example above achieves the same effect as the code below, except that the session objects above preserve encapsulation of session data within their respective namespaces.
Example #3 Old Way: PHP Session Access
$_SESSION['Zend_Auth']['user'] = "myusername";
$_SESSION['Some_Web_Service']['user'] = "mywebusername";
Iterating Over Session Namespaces
Zend_Session_Namespace provides the full
» IteratorAggregate
interface, including support for the foreach statement:
Example #4 Session Iteration
$aNamespace =
new Zend_Session_Namespace('some_namespace_with_data_present');
foreach ($aNamespace as $index => $value) {
echo "aNamespace->$index = '$value';\n";
}
Accessors for Session Namespaces
Zend_Session_Namespace implements the __get(), __set(),
__isset(), and __unset()
» magic methods, which should
not be invoked directly, except from within a subclass. Instead, the normal operators automatically invoke
these methods, such as in the following example:
Example #5 Accessing Session Data
$namespace = new Zend_Session_Namespace(); // default namespace
$namespace->foo = 100;
echo "\$namespace->foo = $namespace->foo\n";
if (!isset($namespace->bar)) {
echo "\$namespace->bar not set\n";
}
unset($namespace->foo);
| Introduction |