Generalized looping possible in pigeonhole sieve?

[Larry Rosenman]

Sieve EXPLICITLY does NOT have a looping construct.


On Thu, Nov 17, 2016 at 4:42 PM, Jeff Kletsky <dovecot at allycomm.com> wrote:

> I'm struggling to achieve the kind of filtering with sieve that I was able
> to do with procmail.
>
> TL;DR
>
> I'd like a way to loop through a set of (address, destination) pairs in
> sieve so that I can maintain the (address, destination) pairs in one place
> and not have to explicitly write scores of nearly identical
>
> [...]
>
> if address :matches ["From", "Sender", "To", "Cc"] "address53" {
>     fileinto "destination53"
> }
>
> if address :matches ["From", "Sender", "To", "Cc"] "address54" {
>     fileinto "destination54"
> }
>
> [...]
>
>
> Longer:
>
> I've been using a table-based dispatch approach with procmail for years
> and it was working reasonably well.
>
> The approach uses list of pairs of address and destination boxes and doing
> a lookup based on the message to be delivered. With procmail, I collected
> the list of addresses and passed them to external scripts to do the lookup.
>
> If I just had a dozen boxes that I deal with, that would be
> straightforward to implement and maintain in sieve. As the list is an order
> of magnitude greater than that, maintaining the list of pairs in an
> external file and programmatically looping through it is a lot easier.
>
> I've looked at vnd.dovecot.execute and it certainly can return a
> destination box name given the input information.
>
> Unfortunately, the construct of (for example)
>
> address :matches "To" "*"'
>
> only returns the first address, not the list of addresses.
>
> I can't see a good way to get all the addressees from sieve to pass to the
> external program. If I have to pass the message (or at least the
> interesting headers) to the external program and then parse the address
> list myself, then I'm nearly all the way to just using a full-on external
> program to parse the whole message.
>
> While I'm not adverse to writing the whole thing in Python (or the like)
> and just using sieve as a thin shell, I'd like to make sure I'm not missing
> something in sieve.
>
> One way to achieve this would be to be able to loop through the pairs and
> using variable substitution for each iteration. I haven't seen anything in
> Dovecot Pigeonhole sieve that allows this.
>
> If you have any ideas on how to harness sieve for this, I'd appreciate it!
>
>
> Jeff
>



-- 
Larry Rosenman                     http://www.lerctr.org/~ler
Phone: +1 214-642-9640 (c)     E-Mail: larryrtx at gmail.com
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