CakePHP: Check if SPECIFIC flash message is set

Question

I have a page with several sections with forms that are submitted from the same page. The forms collapse to save space, but I want to conditionally keep them open if there is an error on submission.

In my controller, I set a specific "key" (see location_key below) for each form, which allows me to echo them in their respective locations:

In controller:

$this->Session->setFlash('You missed something...', 'element_name', array('class'=>'error'), 'location_key');

In view:

$this->Session->flash('location_key')

I'm trying to figure out how to check if $this->Session->flash('location_key') exists. If I do this it works but unsets the flash message:

if ( $this->Session->flash('location_key') ) // = TRUE
    //Do something
$this->Session->flash('location_key') // = FALSE (because it just got called)

How can I test for the presence of this flash message without causing it to go away?

Answer 1

Figured it out! This works:

$this->Session->check('Message.location_key')

It returns true/false depending on whether there are any such flash messages set. ->read() does the same thing, but returns the flash data if there is (any and crucially, it leaves the session var so it can still be echoed later).

Answer 2

Flash messages are (surprise) stored in the session:

public function setFlash($message, $element = 'default', $params = array(), $key = 'flash') {
    CakeSession::write('Message.' . $key, compact('message', 'element', 'params'));
}

To test for the presence of a flash message, test for the equivalent key in the session, e.g.:

if (CakeSession::check('Message.location_key')) {
    ...
}