## 6.6.3 Variables and Scopes

Filters support all the common properties available to controllers and tag libraries, plus the application context:

- request - The HttpServletRequest object
- response - The HttpServletResponse object
- session - The HttpSession object
- servletContext - The ServletContext object
- flash - The flash object
- params - The request parameters object
- actionName - The action name that is being dispatched to
- controllerName - The controller name that is being dispatched to
- grailsApplication - The Grails application currently running
- applicationContext - The ApplicationContext object

However, filters only support a subset of the methods available to controllers and tag libraries. These include:

- redirect - For redirects to other controllers and actions
- render - For rendering custom responses