The HEAD method is identical to GET except that the server MUST NOT return a
message-body in the response. The metainformation contained in the HTTP headers
in response to a HEAD request SHOULD be identical to the information sent in
response to a GET request. This method can be used for obtaining metainformation
about the entity implied by the request without transferring the entity-body
itself. This method is often used for testing hypertext links for validity,
accessibility, and recent modification.