Re: Message ID's

[Dan Weinreb <dlw@exceloncorp.com>]

Thank you very much for your reply.

It seems to me that it's important to be clear about the distinction
between a message-id on one hand, and a URL using the "mid" scheme on
the other hand.  RFC2392 seems to make a clear distinction.

A "mid" scheme URL appears to be a *reference* to a message, where the
message is identified by a globally unique message-id.  The message-id
itself has no need of being a URL nor of having a "mid:" prefix.

In light of this, I think the example on page 25 of the MSS spec on
line 952, namely

  <eb:MessageId>mid:UUID-2</eb:MessageId>

while perfectly legal in the sense that any character string that's
globally unique is an acceptable message-id, is nevertheless
misleading in that "mid:" is normally used as a reference rather than
as a unique ID itself.

The use of "mid:" two lines down, on line 954, also deserves mention:

  <eb:RefToMessageId>mid:UUID-1</eb:RefToMessageId>

Here the "mid:" makes more sense than on line 952, because here we're
making a reference to some other message, and making references to
other messages is what "mid:" is about.  On the other hand, the fact
that we're making a reference is quite clear from the XML tag, and
so the use of "mid:" would not seem to be contributing much.

In the example on page 21, line 746, we see a use of eb:RefToMessageId
*without* the "mid:".  Section 8.4.6.3 says of the contents of the
RefToMessageId element: "When present, it MUST contain the MessageId
value of an earlier ebXML Message to which this message relates."
This seems to be saying that the contents should be the message-id
itself, rather than a "mid:" URL.  Section 8.13.1 contains similar
language.

-- Dan