Controller parameters are available at $this->params in your Cake controller. This variable is used to get data into the controller and provide access to information about the current request. The most common usage of $this->params is to get access to information that has been handed to the controller via POST or GET operations.

$this->data

Used to handle POST data sent from HTML Helper forms to the controller.

// A HTML Helper is used to create a form element

$html->input('User/first_name');

// When rendered as HTML it looks like:

<input name="data[User][first_name]" value="" type="text" />

// And when submitted to the controller via POST,
// shows up in $this->data['User']['first_name']

Array
(
    [data] => Array
        (
            [User] => Array
                (
                    [username] => mrrogers
                    [password] => myn3ighb0r
                    [first_name] => Mister
                    [last_name] => Rogers
                )

        )
)

$this->params['form']

Any POST data from any form is stored here, including information also found in $_FILES.

$this->params['bare']

Stores '1' if the current layout is bare, '0' if not.

$this->params['ajax']

Stores '1' if the current layout is ajax, '0' if not.

$this->params['controller']

Stores the name of the current controller handling the request. For example, if the URL /posts/view/1 was called, $this->params['controller'] would equal "posts".

$this->params['action']

Stores the name of the current action handling the request. For example, if the URL /posts/view/1 was called, $this->params['action'] would equal "view".

$this->params['pass']

Stores the GET query string passed with the current request. For example, if the URL /posts/view/?var1=3&var2=4 was called, $this->params['pass'] would equal "?var1=3&var2=4".

$this->params['url']

Stores the current URL requested, along with key-value pairs of get variables. For example, if the URL /posts/view/?var1=3&var2=4 was called, $this->params['url'] would look like this:

[url] => Array
        (
            [url] => posts/view
            [var1] => 3
            [var2] => 4
        )