dovecot - Mar 2007 - Multiple delivery with LDA+sieve

Hi !

I  am still  a bit  annoyed  with the  way that  Sieve plugin  handles
multiple delivery into the same folder.

For reference :
 http://www.dovecot.org/list/dovecot/2007-January/019029.html

Summary :
 When a same  message (same message-id) is to  be delivered twice into
 the same mailbox, it is delivered twice while I think that the second
 one should be discarded.

Here are a few test cases :
 - you subscribe  to a few mailing lists on topic  "X" and deliver all
   mails from  those mailing lists in  the same folder.  You get twice
   the mails that are crossposted.
 - you subscribe to one mailing list and read it regulary so you don't
   care of  receiving messages from this  mailing list (you  are in Cc
   when someone answers)  in your INBOX. You match on To  or Cc to put
   everything in the same folder.  You get messages twice when you are
   put personally in Cc.
 - you place  a forward from one account to two  of your accounts (one
   is  keeping  backup, the  other  don't  but  delivers faster).  You
   receive all messages twice.

With procmail, I handle those  (real) cases with formail. I can't with
Sieve. I  don't see any interest  in receiving the  same message twice
into the  same mailbox. Is  it possible to  maintain a list  of recent
message-id and mailbox couples to  avoid to deliver again a message to
the same mailbox ?
-- 
Terminate input by end-of-file or marker, not by count.
            - The Elements of Programming Style (Kernighan & Plauger)

On 25.3.2007, at 13.49, Vincent Bernat wrote:
> Is  it possible to  maintain a list  of recent
> message-id and mailbox couples to  avoid to deliver again a message to
> the same mailbox ?
It should be pretty easy to modify the sources to do this. There's  
duplicate.h which provides an API to marking duplicates and checking  
if they exist. It's already used by the Sieve plugin. The duplicate  
database code is pretty simple though and if the file grows large,  
it'll be slow.

I guess this duplicate checking could be done, but I wouldn't want it  
enabled by default.

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On 25/03/2007 15:12, Timo Sirainen wrote:
> I guess this duplicate checking could be done, but I wouldn't want it 
> enabled by default.
You've got to be careful anyway, these so-called duplicates often come 
via different routes (e.g. directly and via a mailing list), may have 
been processed differently over those routes (e.g. have had attachments 
stripped), can't be trusted to have useful addressee fields, and won't 
necessarily arrive in the same order every time, so any rules for 
de-duplicating really have to be left to the mailbox owner and can't 
safely be applied server-wide.

Just my 0.02 currency units of your choice.

Cheers,

John.