Managing User Sessions In ZF
Introduction to Sessions
The success of the web is deeply rooted in the protocol that drives the web: HTTP. HTTP
over TCP is by its very nature stateless, which means that inherently the web is also
stateless. While this very aspect is one of the dominating factors for why the web has
become such a popular medium, it also causes an interesting problem for developers that
want to use the web as an application platform.
The act of interacting with a web application is typically defined by the sum
of all requests sent to a web server. Since there can be many consumers being served
simultaneously, the application must decide which requests belong to which consumer. These
requests are typically known as a "session".
In PHP, the session problem is solved by the session extension which utilizes some state
tracking, typically cookies, and some form of local storage which is exposed via the
$_SESSION superglobal. In Zend Framework, the component Zend_Session adds value to the php
session extension making it easier to use and depend on inside object-oriented
applications.
Basic Usage of Zend_Session
The Zend_Session component is both a session manager as well as an API for
storing data into a session object for long-term persistence. The Zend_Session API is
for managing the options and behavior of a session, like options, starting and stopping
a session, whereas Zend_Session_Namespace is the actual object used to store data.
While its generally good practice to start a session inside a bootstrap process, this
is generally not necessary as all sessions will be automatically started upon the first
creation of a Zend_Session_Namespace object.
Zend_Application is capable of configuring Zend_Session for you as part of the
Zend_Application_Resource system. To use this, assuming your project uses
Zend_Application to bootstrap, you would add the following code to your
application.ini file:
As you can see, the options passed in are the same options that you'd expect to find
in the ext/session extension in PHP. Those options setup the path to the session
files where data will be stored within the project. Since ini files can additionally
use constants, the above will use the APPLICATION_PATH constant and relatively point
to a data session directory.
Most Zend Framework components that use sessions need nothing more to use Zend_Session.
At this point, you an either use a component that consumes Zend_Session, or start
storing your own data inside a session with Zend_Session_Namespace.
Zend_Session_Namespace is a simple class that proxies data via an easy to use API
into the Zend_Session managed $_SESSION superglobal. The reason it is called
Zend_Session_Namespace is that it effectively namespaces the data inside $_SESSION, thus
allowing multiple components and objects to safely store and retrieve data. In the
following code, we'll explore how to build a simple session incrementing counter, starting
at 1000 and resetting itself after 1999.
counter)) {
$mysession->counter = 1000;
} else {
$mysession->counter++;
}
if ($mysession->counter > 1999) {
unset($mysession->counter);
}
]]>
As you can see above, the session namespace object uses the magic __get, __set,
__isset, and __unset to allow you to seemlessly and fluently interact with the session.
The information stored in the above example is stored at $_SESSION['mysession']['counter'].
Advanced Usage of Zend_Session
Addionally, if you wanted to use the DbTable
save handler for Zend_Session, you'd add the following code to your application.ini: