instances of this class provide a variety of ways to match on the
Request method.
Examples:
method GET -- match GET or HEAD
method [GET, POST] -- match GET, HEAD or POST
method HEAD -- match HEAD /but not/ GET
method (== GET) -- match GET or HEAD
method (not . (==) DELETE) -- match any method except DELETE
method () -- match any method
As you can see, GET implies that HEAD should match as well. This is to
make it harder to write an application that uses HTTP incorrectly.
Happstack handles HEAD requests automatically, but we still need to
make sure our handlers don't mismatch or a HEAD will result in a 404.
If you must, you can still do something like this to match GET without
HEAD:
guardRq ((== GET) . rqMethod)