The Method token indicates the method to be performed on the resource identified by the Request-URI. The method is case-sensitive.
Method = "GET" ; Section 8.1 | "HEAD" ; Section 8.2 | "POST" ; Section 8.3 | extension-method extension-method = token
The list of methods acceptable by a specific resource can change dynamically; the client is notified through the return code of the response if a method is not allowed on a resource. Servers should return the status code 501 (not implemented) if the method is unrecognized or not implemented.
The methods commonly used by HTTP/1.0 applications are fully defined in Section 8.