Hi Gordon, Thanks very much for taking the time to respond to this.
> On 07/30/2010 01:07 AM, Steve Huston wrote: > > I'm updating the Wireshark AMQP dissector to understand > AMQP 0-10 and > > using Qpid C++ as the test for it. I am confused about one > section of > > the spec and would like some clarification please. > > > > The Session class has a session.header domain that says: > "The session > > header appears on commands after the class and command id, > but prior > > to command arguments." It's a 1-byte header. The > session.header domain > > isn't mentioned anywhere else I can find > > It is also referenced in the diagram in section 5.8 of the main > document, entitled Commands but it just states the same thing in > pictorial form. Thanks for that reference as well. > > and it doesn't appear in > > Qpid-originated Session assemblies. > > I believe that the header is indeed present on the wire as > expected for > commands (after the class and command id, before the command > arguments). > I re-checked with c++ but it must be there for Java and > python as well. > > The header is a sized struct so has one octet for a byte count, it is > also packed and has another byte for the flags and the only > field in it > is the sync flag which represented solely in the packing flags. The > valid values in practice are therefore 01 00 (sync flag not > set) and 01 > 01 (sync flag set). > > In the c++ codebase there is a generated class > <build-dir>/src/qpid/framing/Header.h and this is used in > <src-dir>/src/qpid/framing/ModelMethod.h which is the super > class of all > 'method body' classes representing commands. Ah, that was my confusion... It's only on commands, not on controls. Since it was described in the Session class domain, I thought the header would be on only Session assemblies. However, Session has all controls, not commands. And the commands in other classes reference Session.header. Not that clear, but I get it now. Thanks! -Steve --------------------------------------------------------------------- Apache Qpid - AMQP Messaging Implementation Project: http://qpid.apache.org Use/Interact: mailto:dev-subscr...@qpid.apache.org
