Add date header to incoming email with Sieve

Question

I'm looking for a way to do in Sieve something that I've been doing in Procmail for years, which is to insert an unambiguous date header in incoming messages that makes it clear to me -- independent of buried "received" headers from possibly multiple servers and however my mail client interprets the date the message was sent -- when my server received the message. This is how I did it in Procmail:

# First create the "date_received" variable for my time zone:
date_received=`/bin/date -ud '+2 hour' +'%A %Y-%m-%d %H:%M:%S +0200'`

# Second, insert the header containing the date_received variable:
:0 fh w
| formail -i "X-Local-Date-Received: $date_received"

I found "addheader" (RFC 5293) which will, obviously, add a header, but due to something else I read (sorry, don't remember where) I believe that Sieve won't run the "date" command in the shell due to either a limitation or an intended (and understandable) preference not to run shell commands for security reasons.

Other possibly useful information: I'm doing this through Roundcube 1.3.6, but I have a feeling (also due to something I read) that Roundcube might overwrite a custom Sieve filter set if I edit the raw code within Roundcube. If necessary I'm quite happy to edit or create a Sieve configuration file on the server directly to achieve this for all users on the server, but having run Sendmail and Procmail for years I'm unsure of the best place to do this.

EDIT:

As a test in Roundcube I added this at the top of my Sieve filter set:

require ["fileinto","editheader"];
# rule:[test editheader]
if true
{
addheader "X-Test-Header" "This is a test header.";
}

I didn't actually add the line "require ["fileinto","editheader"];"; I just added "editheader" to the existing line at the top of the filter set, like so:

require ["copy","fileinto","regex","editheader"];

I expect this to add ...

X-Test-Header: This is a test header.

... to every incoming message, but Roundcube won't let me save it:

An error occurred.
Unable to save filter. Server error occurred.

A search for this error returns one related result, with no solution posted.

I'm not intending to focus on Roundcube, however. Like I said earlier, I'll add this Sieve filter from the command line if necessary.

Answer 1

The Pigeonhole Sieve Editheader extension isn't available by default. Per its documentation, you need to ensure it's added in your list of sieve extensions on the server:

plugin {
  # Use editheader
  sieve_extensions = +editheader
}

If you want to run arbitrary scripts using sieve on Dovecot like you can with procmail, then you can use its external programs plugins, configure in Dovecot which external programs you want to allow users to use, and then the users can use the "vnd.dovecot.execute" extension to run those programs. You might be able to use this to port over whatever scripts you used with procmail.

In the general case, the purpose of sieve is for users to be able to configure their own mail filtering, while it seems like you're trying to actually do something globally for the server. Dovecot should add its own Received header when it processes the mail, which is the standard method for marking when a mail system gets a message, so it's not clear to me why you're not just using that, or what changes you want to make to its default behavior. It may be that what you're looking to do may be better handled in your mail transport agent rather than in your mail delivery agent.

Answer 2

You can use date plugin. See: rfc5260:

require "date";
require "editheader";

if currentdate :matches "std11" "*" {
    addheader :last "X-Local-Date-Received" "${1}";
}

Answer 3

Here is my sieve script that converts Received to Date:

require "editheader";
require "regex";
require "variables";

if not exists "Date" { 
    if header :regex "Received" "^from[[:space:]]+.*[[:space:]]+by[[:space:]]+mail.mydomain.com[[:space:]]+with[[:space:]]+.*[[:space:]]+for[[:space:]]+.*;(.*)$" {
        addheader :last "Date" "${1}";
    }
}

Note that mail.mydomain.com is a stand-in for the actual mail server address, which means it only matches the header when the message was received on a specific mail server. I made this work with dovecot-2.3.5.1