Sessions

The CakePHP session component provides a way to persist client data between page requests. It acts as a wrapper for the $_SESSION as well as providing convenience methods for several $_SESSION related functions.

Sessions can be persisted in a few different ways. The default is to use the settings provided by PHP; however, other options exist.

cake
Saves the session files in your app’s tmp/sessions directory.
database
Uses CakePHP’s database sessions.
cache
Use the caching engine configured by Cache::config(). Very useful in conjunction with Memcache (in setups with multiple application servers) to store both cached data and sessions.
php
The default setting. Saves session files as indicated by php.ini

To change the default Session handling method alter the Session.save Configuration to reflect the option you desire. If you choose ‘database’ you should also uncomment the Session.database settings and run the database session SQL file located in app/config

To provide a custom configuration, set Session.save Configuration to a filename. CakePHP will use your file in the CONFIGS directory for the settings.

// app/config/core.php
Configure::write('Session.save','my_session');

This will allow you to customize the session handling.

// app/config/my_session.php
//
// Revert value and get rid of the referrer check even when,
// Security.level is medium
ini_restore('session.referer_check');

ini_set('session.use_trans_sid', 0);
ini_set('session.name', Configure::read('Session.cookie'));

// Cookie is now destroyed when browser is closed, doesn't
// persist for days as it does by default for security
// low and medium
ini_set('session.cookie_lifetime', 0);

// Cookie path is now '/' even if you app is within a sub
// directory on the domain
$this->path = '/';
ini_set('session.cookie_path', $this->path);

// Session cookie now persists across all subdomains
ini_set('session.cookie_domain', env('HTTP_BASE'));

Methods

The Session component is used to interact with session information. It includes basic CRUD functions as well as features for creating feedback messages to users.

It should be noted that Array structures can be created in the Session by using dot notation. So User.username would reference the following:

array('User' =>
        array('username' => '[email protected]')
);

Dots are used to indicate nested arrays. This notation is used for all Session component methods wherever a $name is used.

write

write($name, $value)

Write to the Session puts $value into $name. $name can be a dot separated array. For example:

$this->Session->write('Person.eyeColor', 'Green');

This writes the value ‘Green’ to the session under Person => eyeColor.

setFlash

setFlash($message, $element = 'default', $params = array(), $key = 'flash')

Used to set a session variable that can be used for output in the View. $element allows you to control which element (located in /app/views/elements) should be used to render the message in. In the element the message is available as $message. If you leave the $element set to ‘default’, the message will be wrapped with the following:

<div id="flashMessage" class="message"> [message] </div>

$params allows you to pass additional view variables to the rendered layout. $key sets the $messages index in the Message array. Default is ‘flash’.

Parameters can be passed affecting the rendered div, for example adding “class” in the $params array will apply a class to the div output using $session->flash() in your layout or view.

$this->Session->setFlash('Example message text', 'default', array('class' => 'example_class'))

The output from using $session->flash() with the above example would be:

<div id="flashMessage" class="example_class">Example message text</div>

read

read($name)

Returns the value at $name in the Session. If $name is null the entire session will be returned. E.g.

$green = $this->Session->read('Person.eyeColor');

Retrieve the value Green from the session.

check

check($name)

Used to check if a Session variable has been set. Returns true on existence and false on non-existence.

delete

delete($name)

Clear the session data at $name. E.g.

$this->Session->delete('Person.eyeColor');

Our session data no longer has the value ‘Green’, or the index eyeColor set. However, Person is still in the Session. To delete the entire Person information from the session use.

$this->Session->delete('Person');

destroy

The destroy method will delete the session cookie and all session data stored in the temporary file system. It will then destroy the PHP session and then create a fresh session.

$this->Session->destroy()

error

error()

Used to determine the last error in a session.