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Re: "Do not CC me"

On Mon, 26 Nov 2012, Jakub Wilk wrote:
> * Dmitrijs Ledkovs <xnox@debian.org>, 2012-11-26, 00:19:
> >If your e-mail processing machinery cannot handle duplicate
> >messages (due to cross-postings and CC's), maybe you should get an
> >a better email processing machinery. Receiving duplicate emails is
> >inevitable, and trivial to deal with.
> Oh really? I've always wondered how is this supposed to work.

Well, the software to do it is around for more than 15 years.  Google for
"procmail duplicate suppression".

Basically you keep a database of the message-ids seen in the last "n" days,
and don't deliver them again.  You do it per-folder or system-wide or in
whatever way you want, by using separate databases.

Nowadays there is an added aggravation: if anyone worth of notice uses
Outlook, you need to key on envelope sender+recipient+message-id to work
around some atrocious bugs in Outlook's message-id handling.

I just store everything in Cyrus IMAPd 2.4, and tell it using a folder
annotation whether it should drop or store duplicates that end up sorted to
that folder.

> Let's imagine I received a mail, read it, decided it's not
> important, and deleted it. 5 minutes later another mail with
> different contents and headers but the same message-id is received.
> How do you deal with such situation "trivially"? Do you have some
> kind of AI to decide whether this is the "same" message or not?

A duplicate suppresion database does not even require a state machine, let
alone an AI...

  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh

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