I've been going over the callout protocol requirements and OCP, and
find them in generally good agreement. I don't fully understand
the requirements, though and have a couple of questions about them
and OCP.
First, I know I asked about whether or not a transaction was supposed
to be kept on a single connection, but I cannot find my question or
the answer in any archive, so, annoyingly to everyone, including
myself, I need to ask again.
If I am reading things correctly, the requirements allow several
"connections" over one transport connection, but OCP forbids it.
Is there disagreement? If not, which notion is correct?
The requirements mention "keep-alives" and "heartbeats". Was there
any intent to require heartbeat support? OCP does not use them,
which is fine with me.
Reviewing the messages on this list, I find myself deeply uncertain
about what would be in "OCP/HTTP bindings". Would it be an encoding
of the OCP protocol elements (transaction start, transaction id, etc.)
as HTTP-style headers? In order to allow someone to write an Apache
module for OCP and make use of the HTTP header parsing libraries, for
example? And bring in all the baggage about chunking? If so, we need
to state this somewhere, and say why we are doing this, rather than
defining protocol-independent bindings. The "application agnostic"
stuff seems to lead one to expect protocol-independent metadata. This
is why I am deeply confused. Further, if there is a truly application
independent encoding, say, for mime parts, then why not just use this
as the single encoding? At one time it was very important to use
HTTP bindings for this code reuse purpose, but I'm not sure that is
still the case. Can we document a decision on this point?
OCP's negotiation section hints at a rich set of operations; do
we need more than the usual "here's my menu" and "here's my selection
from your menu" ?
I confess to not understanding the big diagram in OCP; it may be an
elegant way to convey information, if I only understood it. Where are
the "data have" messages? Are those "OCP messages" in the last box?
What are "connection C" and "connection G" ?
I cannot keep myself from stumbling over "application message" time and
again. And again. The stuff between the OPES processor and callout
server that might be encapsulated data coming from or going to the
proxied transaction ... can that have an unambiguous name, like "zinc",
if there's nothing better?
Hilarie