capiCrimm is proud to present you this little tip:

Getting Post values as a method argument.

Tags: argument controller get post

You can use 

def foo(apple)
  @out << apple
end

and http::/url.com/foo/echo will echo echo to the screen. However nothing will be passed if you pass apple as a post value from say a form. The workaround is quite simple...

def foo(apple=@request['apple'])
  @out << apple
end

:D