By default CakePHP uses the session timeout value in php.ini

But sometimes you might want to specify a very short Session timeout for testing your code

To do that you open Config/core.php and add a value to the "Session" Configure::write area

Configure::write('Session', array(
		'defaults' => 'php',
                'timeout' => 1 // 1 minute for testing
	));

The reason I needed to shorten my timeout was that I was creating jquery mobile page that did an ajax request to update itself and when the session had expired I needed to test the error: block of the ajax request. I was using the CakePHP ajax Js Helper

I've recently removed all references to the JsHelper from my CakePHP application for a number of reasons:

1. As far as someone on the cakephp IRC channel it's not going to be a part of Cake 3
2. When you use the link method and you have about 160 links on a page you get 160 $.ajax({}) blocks embedded in your page
3. When you try and say cache that code to disk cake didn't seem to delete the temporary files so  you had a growing number of used once files in webroot/js (which had to be writeable to allow the files to be generated)
4. You can write plain jquery 1 or 2 blocks of plain jquery to replace the autogenerated code and it's a lot smaller and simple

// this creates a <a href=""> link
// and performs an ajax call as it's 
// action

// 
echo $this->Js->link( 
        $map['territory_number'], // This is the link text
        array( // this is the url it submits to
               'controller' => 'maps',
               'action' => 'view_details',
                $map['id']
        ),  
        array(
               'method' => 'GET', // use GET which is the default
               'update' => "#" . 'container-' . $key  , // element on page to update with the content from the reply
               'before' =>  '$.mobile.loading("show");',
               'success' => '$.mobile.loading("hide");',
               'error' => '$.mobile.loading("hide"); $("#error-pop-error").html(errorThrown); $("#error-pop").popup(); $("#error-pop").popup("open");',
               //'confirm' => 'Y\'all really want to do this?',
               'class' => 'my-btn ' . $class
        )
)