Support bracketed prefixes in subject as filters

Bug #1082495 reported by Gordon P. Hemsley
This bug affects 1 person
Affects Status Importance Assigned to Milestone
GNU Mailman

Bug Description

Many large mailing lists use bracketed prefixes in subjects as a way to filter messages into smaller buckets, allowing some subscribers to read all mail sent to the list while allowing others to filter messages (in their mail client) to read only the messages they are interested in.

For example, the W3C's www-style mailing list uses these tags to filter messages based on which CSS spec they refer to. Thus, a subject line that begins "[css3-fonts]" will be assumed to be about only the css3-fonts spec, with a target audience of only those interested in that particular spec and not, say, the css3-flexbox spec (whose subject lines would be prefixed with "[css3-flexbox]").

To handle this, the Mailman archive interface would provide an option to filter only on particular prefixes (as well as messages that don't have any prefixes), allowing a user of the archive to use it as they otherwise would, but filtering the output such that they only see the messages they want to see, instead of the whole archive.

In addition, it would be helpful to allow mailing lists to automatically prefix subject lines when the message is sent to an e-mail address using a plus alias.

For example, sending mail to <email address hidden> would prefix the subject line of the message with "[css3-fonts]" in the message sent to subscribers and in the archive, whereas sending mail to <email address hidden> would prefix the message with "[css3-flexbox]".

It should also be allowed to have multiple prefixes on a message, and having such messages be treated as if they had any prefix individually. In terms of plus aliasing, there are two ways to handle it: (1) allow aliases to specify multiple prefixes in a plus alias using some separator (e.g. a comma: www-style+css3-fonts,<email address hidden>); or (2) detecting and intercepting when a single message was sent to multiple e-mail addresses with different plus aliases for a single mailing list (e.g. sending the same e-mail to both <email address hidden> and <email address hidden>), treating it as a single message with multiple subject prefixes when sent to subscribers or stored in the archive.

Now, I understand that this is likely a huge undertaking, but I think it would go a long way to helping users with large and diverse mailing lists.

[EDIT: It appears the W3C may not actually use Mailman. But my point is still the same, so take my usage of W3C e-mails as a hypothetical example, if necessary.]

Tags: mailman3
Revision history for this message
Barry Warsaw (barry) wrote :

Many similar ideas are being explored on the mailman-developers mailing list, under the 'dlist' thread. I suggest engaging in that thread to put forth these ideas.

tags: added: mailman3
description: updated
Barry Warsaw (barry)
Changed in mailman:
importance: Undecided → Wishlist
Revision history for this message
Gordon P. Hemsley (gphemsley) wrote :

I sent an e-mail to the list a few hours ago, but it doesn't appear in the archive. Can you check on that?

Revision history for this message
Mark Sapiro (msapiro) wrote :

As it says at <> "We have set the mailman-developers list to moderate all new users because of a recent problem with some people subscribing to this list and then posting messages that belong elsewhere, often messages that belong on mailman-users instead." Moderators are not online 24-7. Your post has now been accepted and your moderated bit cleared.

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Gordon P. Hemsley (gphemsley) wrote :

Oh, sorry. I admit I didn't read that. I just assumed that I would get a notification if my message was moderated.

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Sandesh Kumar Agrawal (sakuag333) wrote :

I have coded such things in C++, so i am really interested in adding this feature... But i am new to mailman and don't know how to proceed with it. Can u please help me out regarding where should i start ?


Revision history for this message
Terri (terriko) wrote :

I'm currently working on adding dynamic sublists (dlists) to mailman 3. It's a feature that Systers wrote for Mailman 2.1 that allows dynamic creation of "sublists" that people can subscribe or unsubscribe from within a list. Currently it uses the email address to do the filtering much like you described, but doesn't do the prefixes.

Robin and I hoping to have the port of the dlist code done soon, probably in January, with the goal to have the code be part of the Mailman 3.1 release. Once it's in I think it wouldn't be too much more work to add the bracketed prefixes, perhaps as a configurable option for dlist enabled lists. It might even be a feasible project for a Google Summer of Code student at that point.

So, in short, some of the necessary code already exists for Mailman 2.1, it's actively being ported (as in, Robin and I are trying to get together biweekly and hack on it), and it's probably not as huge an undertaking as you imagined as a result. Horray!

Revision history for this message
Abhilash Raj (raj-abhilash1) wrote :

This bug has been moved to the new gitlab repo here:

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