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Session

As a natural counterpart to the Session Component, the Session Helper replicates most of the components functionality and makes it available in your view. The Session Helper is no longer automatically added to your view — so it is necessary to add it to the $helpers array in the controller.

The major difference between the Session Helper and the Session Component is that the helper does not have the ability to write to the session.

As with the Session Component, data is written to and read by using dot separated array structures.

array('User' =>
        array('username' => 'super@example.com')
);

Given the previous array structure, the node would be accessed by User.username, with the dot indicating the nested array. This notation is used for all Session helper methods wherever a $key is used.

If you have Session.start set to false in your config/core.php, you need to call $session->activate(); in your view before you can use any other method of Session helper. Just like you need to call $this->Session->activate(); in your controller to activate Session component.

Methods

read($key)

Read from the Session. Returns a string or array depending on the contents of the session.

id()

Returns the current session ID.

check($key)

Check to see if a key is in the Session. Returns a boolean on the key’s existence.

flash($key)

This will return the contents of the $_SESSION.Message. It is used in conjunction with the Session Component’s setFlash() method.

error()

Returns the last error in the session if one exists.

flash

The flash method uses the default key set by setFlash(). You can also retrieve specific keys in the session. For example, the Auth component sets all of its Session messages under the ‘auth’ key

// Controller code
$this->Session->setFlash('My Message');

// In view
echo $this->Session->flash();
// outputs "<div id='flashMessage' class='message'>My Message</div>"

// output the AuthComponent Session message, if set.
echo $this->Session->flash('auth');

Using Flash for Success and Failure

In some web sites, particularly administration backoffice web applications it is often expected that the result of an operation requested by the user has associated feedback as to whether the operation succeeded or not. This is a classic usage for the flash mechanism since we only want to show the user the result once and not keep the message.

One way to achieve this is to use Session->flash() with the layout parameter. With the layout parameter we can be in control of the resultant html for the message.

In the controller you might typically have code:

if ($user_was_deleted) {
    $this->Session->setFlash('The user was deleted successfully.', 'flash_success');
} else {
    $this->Session->setFlash('The user could not be deleted.', 'flash_failure');
}

The flash_success and flash_failure parameter represents an element file to place in the root app/views/elements folder, e.g. app/views/elements/flash_success.ctp, app/views/elements/flash_failure.ctp

Inside the flash_success element file would be something like this:

<div class="flash flash_success">
    <?php echo $message ?>
</div>

The final step is in your main view file where the result is to be displayed to add simply

<?php echo $this->Session->flash(); ?>

And of course you can then add to your CSS a selector for div.flash, div.flash_success and div.flash_failure