Add new filtering rules

[tonioo]

From @tonioo on December 4, 2013 15:45

Originally created by Antoine Nguyen on 2012-10-21T10:09:27Z

Check the RFCs to see if other useful rule types (or extensions) exist.

Copied from original issue: modoboa/modoboa#329

[tonioo]

From @kostko on July 8, 2014 16:4

It would be useful to have filtering rules that match List-Id and other mailing list related headers.

[herrbischoff]

One filter I sorely miss is the ability to forward mail to one or multiple addresses white retaining a copy in the original mailbox. This is unfortunately often a requirement in business settings where a temporary worker is assigned an address but the supervisor insists on receiving a copy of every email sent to that address to be sure nothing gets lost.

Any chance that will be implemented soon? If you yourself are too busy, I'd be happy to give it a shot, given some pointers.

[tonioo]

@herrbischoff Do you know the sieve command that would allow this?

[herrbischoff]

@tonioo The respective Sieve command should be like in this context:

require ["copy"];
if header :contains "Subject" "whatever"
{
    redirect :copy "other@example.net";
}

I have found a lot more examples here.

[tonioo]

@herrbischoff Looks like something we can add. I think this feature could interest other people so maybe I propose it through the sponsoring system. What do you think? Would you be ready to participate?

[herrbischoff]

Sure, I'm game. Although I don't quite see how this rather trivial change would need to be sponsored. Maybe you have something more elaborate in mind.

The only change between the existing implementation and my suggested one is as follows. It would boil down to duplicating "Redirect message to" as "Copy message to" with a minimal change.

Redirect message to

# Filter: Test
if allof (header :contains "From" "name@domain.com") {
    redirect "othername@domain.com";
}

Copy message to

# Filter: Test
if allof (header :contains "From" "name@domain.com") {
    redirect :copy "othername@domain.com";
}

That's all really. If I was able to figure out how you create the Sieve entries, I would make the change to the code myself. The solution to include multiple addresses shouldn't be too hard as well — just separate by commas. This however appears to go against the current behavior of the other multiple address fields.

I was actually surprised to not see this function being there in the first place. Practically all mail servers I have dealt with over the years had this implemented as a basic function.

[tonioo]

That change would also require to modify the rule editor (the GUI) to add a "keep copy" option when a user select the redirect action. And it would also require to modify the sievelib package because it currently does not support the :copy extension. I think we are on the same level of work than this feature: https://modoboa.org/en/sponsor/3/.

[herrbischoff]

I see. Thanks for clearing that up. Does that mean I would have to sponsor the full amount or is this a kind of crowdsourcing?

[tonioo]

This is a crowdfunding mechanism and you don't have to sponsor if you don't want to ;)

[herrbischoff]

Great, good to hear. I'll very likely be participating though. ;) I really appreciate your work on Modoboa.