[Mailman-Developers] Re: Please stop the cross posting

[Christopher G. Petrilli]

On Fri, Jan 29, 1999 at 07:24:21PM +0100, Christian Tismer wrote:
> > You're probably right - the simpler approach would prevent alternation
> > across lists from compounding the respective prefixes.  (Though the idea
> > of messages alternating from list to list gives me the willies, but that's
> > besides the point...-)
> 
> It basically appeared to me as bad manners to reply to 
> cross-posted messages in a zig-zag. On the other hand, if somebody
> is really on one list and not on the other, this is the only
> way that works. That thread on XML/Zope sigs became really 
> unreadable since prefixes piled up.

I'm sure I was partially to blame for that one, unfortunately it's easy
to get confused, plus sometimes I get them in different orders, and I
usually respond to the first example :-)  Oh well, the human brain works
in mysterious and lousy ways.

> It seems to be hard to tackle this in a more intelligent way.
> Ok, we can prevend prefixes from stacking.
> But the bigger problem which hurts at the same time (See
> Chris Petrilli's message) is that you get these crossposted
> things twice, also.

Also, I think it should be possible to prevent xposts period... At least
if the lists are hosted on the same machine... or maybe even an ability
to define lists that aren't allowed to be xpoststed to... I dunno, this
needs to be thought out more.  I have some ideas about how to
restructure the mailing list delivery stuff so that it will not send out
multiple copies to the same person through different lists.

> I don't see an easy way to avoid this when cross posting is allowed.
> One way would be this:
> 
> When Mailman receives a post, it can see all the recipients,
> especially it can see its own hostname, with different
> mailing lists. Unfortunately, the receiving process will
> duplicate the message and send it to the different aliases,
> one for each list. To capture this, sendmail must be intercepted
> by something like procmail (just as an example) which first makes
> sure that only one list gets that message.

I don't think this belongs in the MTA, it belongs in the mailing list
manager... but that's just me... Also, remember that a lot of us (myself
for example) don't use Sendmail any more...

> The one list which receives the message now reads the recipient
> list, and temporarily merges the user lists of the mentioned
> mailing lists into one. This could make sure that you don't
> get a duplicate message.

Hmm... I'll try and write down my ideas for a more hmm, "elegant"
solution, at least in my mind... think garbage collection, it's a
bizarre premise, but... 

Basically, you have a list of all recipients on all lists merged
together, you then have a list of messages that need to be delivered to
recipients with certain interests... you can then attach this message
object to all the recipients (via whatever method), thereby determining
whether or not the recipient will already be receiving the message.

I've written (a long time ago) a Usenet server that worked on a similar
principle... was quite quick, and very effecient.  It was in C, but I
can't imagine that it should be that hard in Python... this is NOT a
Mailman 1.x exercise :-)

Chris
-- 
| Christopher Petrilli
| petrilli@amber.org