[Kolab-devel] IMAP Flags for E-mail Tags?

[pb at p-b.me]

Good morning,

Firstly, my apologies if this has previously been discussed or is
answered in documentation: I have searched through what is publicly
available but couldn't find anything conclusive.

I notice that e-mail (and in fact general groupware-item) tagging is
implemented via `tag configuration objects' which store both
meta-data and membership-data for each defined tag. I was wondering
if there was a reason why this route was selected instead of
utilising the `FLAGS' / keywords functionality provided by IMAP4r1
to store the tag membership data?

My reasons for asking are twofold:

1) Flags/keywords can trivially be applied to incoming mail messages via
Sieve rules using the Imap4Flags Extension to Sieve (RFC5232) (which is
supported by Cyrus), whereas this does not presently appear to be so
for Kolab tags;

2) Flags/keywords, being a part of the IMAP spec., can be understood
by any IMAP4 client: this is specifically of use on mobile devices,
where the UI afforded by a native app (of which there are already
some in existence that support Flags) is preferable to that provided
through a web browser.

Following from this, as someone interested in contributing to the
project in order to have these features available, would there be
architectural problems in introducing this? If so, are there ways
that the same effects could be achieved using the configuration
objects (namely, auto-application of tags to incoming mail, and
access to tags in a native app on a mobile [Android] device)?
If not, in which areas of the codebase would I need to start looking?

Kind regards,

Peter Bridgman