Content of the response.
Can be used as a response to return when a user must be logged to access a page.
When constructing a view, the response object must be populated and returned. The response is then displayed to the visitor. The interest of using a response object is that we can run a post filter action on the response. For example you can run a filter that is checking that all the output is valid HTML and write a logfile if this is not the case.
__construct( $request, $loginurl = null)
The $request object is used to know what the post login redirect url should be.
If the action url of the login page is not set, it will try to get the url from the login view from the 'login_view' configuration key.