Sessions¶

Session Configuration¶

Session configuration is generally defined in /config/app.php. The available options are:

• Session.timeout - The number of minutes a session can remain ‘idle’. If no request is received for timeout minutes, CakePHP’s session handler will expire the session. You can set this option to 0 to disable server side idle timeouts.

• Session.defaults - Allows you to use the built-in default session configurations as a base for your session configuration. See below for the built-in defaults.

• Session.handler - Allows you to define a custom session handler. The core database and cache session handlers use this. See below for additional information on Session handlers.

• Session.ini - Allows you to set additional session ini settings for your config. This combined with Session.handler replace the custom session handling features of previous versions

• Session.cookie - The name of the cookie to use. Defaults to value set for session.name php.ini config.

• Session.cookiePath - The url path for which session cookie is set. Maps to the session.cookie_path php.ini config. Defaults to base path of app.

CakePHP’s defaults session.cookie_secure to true, when your application is on an SSL protocol. If your application serves from both SSL and non-SSL protocols, then you might have problems with sessions being lost. If you need access to the session on both SSL and non-SSL domains you will want to disable this:

Configure::write('Session', [
    'defaults' => 'php',
    'ini' => [
        'session.cookie_secure' => false
    ]
]);

CakePHP also sets the SameSite attribute to Lax by default for session cookies, which helps protect against CSRF attacks. You can change the default value by setting session.cookie_samesite php.ini config:

Configure::write('Session', [
    'defaults' => 'php',
    'ini' => [
        'session.cookie_samesite' => 'Strict',
    ],
]);

The session cookie path defaults to app’s base path. To change this you can use the session.cookie_path ini value. For example if you want your session to persist across all subdomains you can do:

Configure::write('Session', [
    'defaults' => 'php',
    'ini' => [
        'session.cookie_path' => '/',
        'session.cookie_domain' => '.yourdomain.com',
    ],
]);

By default PHP sets the session cookie to expire as soon as the browser is closed, regardless of the configured Session.timeout value. The cookie timeout is controlled by the session.cookie_lifetime ini value and can be configured using:

Configure::write('Session', [
    'defaults' => 'php',
    'ini' => [
        // Invalidate the cookie after 30 minutes
        'session.cookie_lifetime' => 1800
    ]
]);

The difference between Session.timeout and the session.cookie_lifetime value is that the latter relies on the client telling the truth about the cookie. If you require stricter timeout checking, without relying on what the client reports, you should use Session.timeout.

Please note that Session.timeout corresponds to the total time of inactivity for a user (i.e. the time without visiting any page where the session is used), and does not limit the total amount of minutes a user can stay active on the site.

Built-in Session Handlers & Configuration¶

CakePHP comes with several built-in session configurations. You can either use these as the basis for your session configuration, or you can create a fully custom solution. To use defaults, simply set the ‘defaults’ key to the name of the default you want to use. You can then override any sub setting by declaring it in your Session config:

Configure::write('Session', [
    'defaults' => 'php'
]);

The above will use the built-in ‘php’ session configuration. You could augment part or all of it by doing the following:

Configure::write('Session', [
    'defaults' => 'php',
    'cookie' => 'my_app',
    'timeout' => 4320 // 3 days
]);

The above overrides the timeout and cookie name for the ‘php’ session configuration. The built-in configurations are:

• php - Saves sessions with the standard settings in your php.ini file.

• cake - Saves sessions as files inside tmp/sessions. This is a good option when on hosts that don’t allow you to write outside your own home dir.

• database - Use the built-in database sessions. See below for more information.

• cache - Use the built-in cache sessions. See below for more information.

'Session' => [
    'handler' => [
        'engine' => 'DatabaseSession',
        'model' => 'CustomSessions',
    ],
]

'Session' => [
    'defaults' => 'database'
]

CREATE TABLE `sessions` (
  `id` char(40) CHARACTER SET ascii COLLATE ascii_bin NOT NULL,
  `created` datetime DEFAULT CURRENT_TIMESTAMP, -- Optional
  `modified` datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, -- Optional
  `data` blob DEFAULT NULL, -- for PostgreSQL use bytea instead of blob
  `expires` int(10) unsigned DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

'Session' => [
    'defaults' => 'database',
    'handler' => [
        'engine' => 'DatabaseSession',
        'model' => 'CustomSessions',
    ],
]

Configure::write('Session', [
    'defaults' => 'cache',
    'handler' => [
        'config' => 'session',
    ],
]);

'Session' => [
    'defaults' => 'php',
],

Setting ini directives¶

The built-in defaults attempt to provide a common base for session configuration. You may need to tweak specific ini flags as well. CakePHP exposes the ability to customize the ini settings for both default configurations, as well as custom ones. The ini key in the session settings, allows you to specify individual configuration values. For example you can use it to control settings like session.gc_divisor:

Configure::write('Session', [
    'defaults' => 'php',
    'ini' => [
        'session.cookie_name' => 'MyCookie',
        'session.cookie_lifetime' => 1800, // Valid for 30 minutes
        'session.gc_divisor' => 1000,
        'session.cookie_httponly' => true
    ]
]);

Creating a Custom Session Handler¶

Creating a custom session handler is straightforward in CakePHP. In this example we’ll create a session handler that stores sessions both in the Cache (APC) and the database. This gives us the best of fast IO of APC, without having to worry about sessions evaporating when the cache fills up.

First we’ll need to create our custom class and put it in src/Http/Session/ComboSession.php. The class should look something like:

namespace App\Http\Session;

use Cake\Cache\Cache;
use Cake\Core\Configure;
use Cake\Http\Session\DatabaseSession;

class ComboSession extends DatabaseSession
{
    protected $cacheKey;

    public function __construct()
    {
        $this->cacheKey = Configure::read('Session.handler.cache');
        parent::__construct();
    }

    // Read data from the session.
    public function read($id): string
    {
        $result = Cache::read($id, $this->cacheKey);
        if ($result) {
            return $result;
        }

        return parent::read($id);
    }

    // Write data into the session.
    public function write($id, $data): bool
    {
        Cache::write($id, $data, $this->cacheKey);

        return parent::write($id, $data);
    }

    // Destroy a session.
    public function destroy($id): bool
    {
        Cache::delete($id, $this->cacheKey);

        return parent::destroy($id);
    }

    // Removes expired sessions.
    public function gc($expires = null): bool
    {
        return parent::gc($expires);
    }
}

Our class extends the built-in DatabaseSession so we don’t have to duplicate all of its logic and behavior. We wrap each operation with a Cake\Cache\Cache operation. This lets us fetch sessions from the fast cache, and not have to worry about what happens when we fill the cache. In config/app.php make the session block look like:

'Session' => [
    'defaults' => 'database',
    'handler' => [
        'engine' => 'ComboSession',
        'model' => 'Session',
        'cache' => 'apc',
    ],
],
// Make sure to add a apc cache config
'Cache' => [
    'apc' => ['engine' => 'Apc']
]

Now our application will start using our custom session handler for reading and writing session data.

class Session¶

Accessing the Session Object¶

You can access the session data any place you have access to a request object. This means the session is accessible from:

• Controllers

• Views

• Helpers

• Cells

• Components

A basic example of session usage in controllers, views and cells would be:

$name = $this->request->getSession()->read('User.name');

// If you are accessing the session multiple times,
// you will probably want a local variable.
$session = $this->request->getSession();
$name = $session->read('User.name');

In helpers, use $this->getView()->getRequest() to get the request object; In components, use $this->getController()->getRequest().

Reading & Writing Session Data¶

Session::read($key, $default = null)¶

You can read values from the session using Hash::extract() compatible syntax:

$session->read('Config.language', 'en');

Session::readOrFail($key)¶

The same as convenience wrapper around non-nullable return value:

$session->readOrFail('Config.language');

This is useful, when you know this key has to be set and you don’t want to have to check for the existence in code itself.

Session::write($key, $value)¶

$key should be the dot separated path you wish to write $value to:

$session->write('Config.language', 'en');

You may also specify one or multiple hashes like so:

$session->write([
  'Config.theme' => 'blue',
  'Config.language' => 'en',
]);

Session::delete($key)¶

When you need to delete data from the session, you can use delete():

$session->delete('Some.value');

static Session::consume($key)¶

When you need to read and delete data from the session, you can use consume():

$session->consume('Some.value');

Session::check($key)¶

If you want to see if data exists in the session, you can use check():

if ($session->check('Config.language')) {
    // Config.language exists and is not null.
}

Destroying the Session¶

Session::destroy()¶

Destroying the session is useful when users log out. To destroy a session, use the destroy() method:

$session->destroy();

Destroying a session will remove all serverside data in the session, but will not remove the session cookie.

Rotating Session Identifiers¶

Session::renew()¶

While the Authentication Plugin automatically renews the session id when users login and logout, you may need to rotate the session id’s manually. To do this use the renew() method:

$session->renew();

Flash Messages¶

Flash messages are small messages displayed to end users once. They are often used to present error messages, or confirm that actions took place successfully.

To set and display flash messages you should use FlashComponent and FlashHelper