The CakePHP SessionComponent provides a way to persist client data between page requests. It acts as a wrapper for $_SESSION as well as providing convenience methods for several $_SESSION related functions.
Sessions can be configured in a number of ways in CakePHP. For more information, you should see the Session configuration documentation.
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@example.com' ));
Dots are used to indicate nested arrays. This notation is used for all Session component methods wherever a name/key is used.
Write to the Session puts $value into $name. $name can be a dot separated array. For example:
This writes the value ‘Green’ to the session under Person => eyeColor.
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. Reading data that does not exist will return null.
Used to check if a Session variable has been set. Returns true on existence and false on non-existence.
Clear the session data at $name. E.g:
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:
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:
Often in web applications, you will need to display a one-time notification message to the user after processing a form or acknowledging data. In CakePHP, these are referred to as “flash messages”. You can set flash message with the SessionComponent and display them with the SessionHelper::flash(). To set a message, use setFlash:
// In the controller. $this->Session->setFlash('Your stuff has been saved.');
This will create a one-time message that can be displayed to the user, using the SessionHelper:
// In the view. echo $this->Session->flash(); // The above will output. <div id="flashMessage" class="message"> Your stuff has been saved. </div>
You can use the additional parameters of setFlash() to create different kinds of flash messages. For example, error and positive notifications may look differently. CakePHP gives you a way to do that. Using the $key parameter you can store multiple messages, which can be output separately:
// set a bad message. $this->Session->setFlash('Something bad.', 'default', array(), 'bad'); // set a good message. $this->Session->setFlash('Something good.', 'default', array(), 'good');
In the view, these messages can be output and styled differently:
// in a view. echo $this->Session->flash('good'); echo $this->Session->flash('bad');
The $element parameter allows you to control which element (located in /app/View/Elements) should be used to render the message in. In the element the message is available as $message. First we set the flash in our controller:
$this->Session->setFlash('Something custom!', 'flash_custom');
Then we create the file app/View/Elements/flash_custom.ctp and build our custom flash element:
<div id="myCustomFlash"><?php echo h($message); ?></div>
$params allows you to pass additional view variables to the rendered layout. 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 $this->Session->flash() in your layout or view.:
$this->Session->setFlash( 'Example message text', 'default', array('class' => 'example_class') );
The output from using $this->Session->flash() with the above example would be:
<div id="flashMessage" class="example_class">Example message text</div>
To use an element from a plugin just specify the plugin in the $params:
// Will use /app/Plugin/Comment/View/Elements/flash_no_spam.ctp $this->Session->setFlash( 'Message!', 'flash_no_spam', array('plugin' => 'Comment') );
By default CakePHP does not HTML escape flash messages. If you are using any request or user data in your flash messages you should escape it with h when formatting your messages.