Hi,
there has been a lot of discussion back and forth on activation points
and callout modes. But it became quiet last days and we have no consensus
yet I think.
I try to summarize and argue again why some combinations are either
unneeded or not in the agenda's focus. Maybe this helps a little further.
From what we collected in the discussion so far I could see
four theoretical activation points:
1. Receiving email
Do a SMTP dialog with the peer, receiving email from it,
usually storing the emails in a queue and maybe sending on later
2. Stored email in queue
Operate on an email that has been received earlier. Their is
no current SMTP dialog going on
3. Sending email
Do a SMTP dialog with a peer, sending email to it.
4. Proxy (receive and forward)
Having two SMTP dialogs at the same time. Mostly forwarding
commands and replies; often no own email queue
In addition to that there are four modes
A. SMTP command modification
The command is modified by the callout server
B. SMTP command satisfaction
Callout server responds with a SMTP reply (usually an error
message).
C. SMTP reply modification
The SMTP reply is modified by the callout server
D. Email message body modification
Do we need all these and all combinations?
I don't think so:
Re 2: Working on stored emails has more to do with a MIME profile for
OCP than with a SMTP profile. It only operates on the message body
anyway as there is no SMTP dialog going on.
Certainly you could use an OCP client and pretend a SMTP dialog in order
to get a callout server to work on a stored email.
But the more natural profile is OCP/MIME and not OCP/SMTP.
Re C: SMTP reply modification seems to make sense for
- reply logging (so no real modification)
- At activation point 4, when commands and replies are proxied
Re D: When part of OCP/SMTP (not OCP/MIME or alike) this can be
seen as command modification, i.e. it falls back to mode A.
Re 3: Tony and jfcm don't see a use case for this. But most use
cases listed so far do either work at activation points 1 or 3.
There might even be specific callout services that make much more
sense when sending the email (for example: add a footer to the email
that contains a current time stamp, whether condidition, stock price, ...)
Or there might be a corporate email gateway that uses SMTP outbound and
wants to do filtering there but emails are not delivered to that device
via SMTP but some other mail protocol, so that there is no activation
point 1 in the authorotive domain.
In my opinion, activation points 1 and 3 are very similar, make both sense
and don't cost more to be handled both.
Point 4 is special and opens a chance for mode C. (4A and 4B are the same
as 1A and 1B). But the whole scenario becomes more complex. Most use cases
can be done without this. Hilarie sees them as very important.
So my candidates are:
Mandantory:
1A 1B
3A 3B
Optional:
4C
All other combinations are unneeded or out of focus.
Regards
Martin