Symfony - Cookies and Session Management

Symfony HttpFoundation component provides cookie and session management in an object-oriented manner. Cookie provides client-side data storage and it only supports a small amount of data. Usually, it is 2KB per domain and it depends on the browser. Session provides server-side data storage and it supports a large amount of data. Let us see how to create a cookie and session in a Symfony web application.

Cookie

Symfony provides Cookie class to create a cookie item. Let us create a cookie color, which expires in 24 hours with value blue. The constructor parameter of the cookie class is as follows.

• name (type: string) - cookie name
• value (type: string) - cookie value
• expire (type: integer / string / datetime) - expiry information
• path (type: string) - the server path in which the cookie is available
• domain (type: string) – the domain address in which the cookie is available
• secure (type: boolean) - whether the cookie needs to be transmitted in HTTPS connection
• httpOnly (type: boolean) - whether the cookie is available only in HTTP protocol

use Symfony\Component\HttpFoundation\Cookie;  
$cookie = new Cookie('color', 'green', strtotime('tomorrow'), '/', 
   'somedomain.com', true, true);

Symfony also provides the following string-based cookie creation option.

$cookie = Cookie::fromString('color = green; expires = Web, 4-May-2017 18:00:00 +0100; 
path=/; domain = somedomain.com; secure; httponly');

Now, the created cookie needs to be attached to the http response object's header as follows.

$response->headers->setCookie($cookie);

To get the cookie, we can use Request object as follows.

$cookie = $request->cookie->get('color'); 

Here, request->cookie is of type PropertyBag and we can manipulate it using PropertyBag methods.

Session

Symfony provides a Session class implementing SessionInterface interface. The important session API are as follows,

start − Starts the session.

Session $session = new Session(); 
$session->start(); 

invalidate − Clears all session data and regenerates the session ID.

set − Stores data in the session using a key.

$session->set('key', 'value');

We can use any data in the session value, be in simple integer to complex objects.

get − Gets data from the session using the key.

$val = $session->get('key');

remove − Removes a key from the session.

clear − Removes a session data.

FlashBag

Session provides another useful feature called FlashBag. It is a special container inside the session holding the data only during page redirection. It is useful in http redirects. Before redirecting to a page, data can be saved in FlashBag instead of a normal session container and the saved data will be available in the next request (the redirected page). Then, the data will be invalidated automatically.

$session->getFlashBag()->add('key', 'value');  
$session->getFlashBag()->get('key');