func (s *FrameSuite) TestDetermineVersion_IncompatibleVersions(c *C) {
f := frame.New(frame.CONNECT)
f.Header.Add(frame.AcceptVersion, "0.2,0.1,1.3,2.0")
version, err := determineVersion(f)
c.Check(version, Equals, stomp.Version(""))
c.Check(err, Equals, unknownVersion)
}
// Determine the most acceptable version based on the accept-version
// header of a CONNECT or STOMP frame.
//
// Returns stomp.V10 if a CONNECT frame and the accept-version header is missing.
//
// Returns an error if the frame is not a CONNECT or STOMP frame, or
// if the accept-header is malformed or does not contain any compatible
// version numbers. Also returns an error if the accept-header is missing
// for a STOMP frame.
//
// Otherwise, returns the highest compatible version specified in the
// accept-version header. Compatible versions are V1_0, V1_1 and V1_2.
func determineVersion(f *frame.Frame) (version stomp.Version, err error) {
// frame can be CONNECT or STOMP with slightly different
// handling of accept-verion for each
isConnect := f.Command == frame.CONNECT
if !isConnect && f.Command != frame.STOMP {
err = notConnectFrame
return
}
// start with an error, and remove if successful
err = unknownVersion
if acceptVersion, ok := f.Header.Contains(frame.AcceptVersion); ok {
// sort the versions so that the latest version comes last
versions := strings.Split(acceptVersion, ",")
sort.Strings(versions)
for _, v := range versions {
switch stomp.Version(v) {
case stomp.V10:
version = stomp.V10
err = nil
case stomp.V11:
version = stomp.V11
err = nil
case stomp.V12:
version = stomp.V12
err = nil
}
}
} else {
// CONNECT frames can be missing the accept-version header,
// we assume V1.0 in this case. STOMP frames were introduced
// in V1.1, so they must have an accept-version header.
if isConnect {
// no "accept-version" header, so we assume 1.0
version = stomp.V10
err = nil
} else {
err = missingHeader(frame.AcceptVersion)
}
}
return
}