[Dovecot] Feature wish: "Virtual" POP3 folder with IMAP
Hallo,
is it possible to implement a "flat folder view" for POP3 users?
The problem is that POP3 only knows one folder: INBOX. Now, if a user logs in via POP3, he won't see messages that live outside the INBOX folder - this could be e.g. a *SPAM*-flagged message moved to another folder via Sieve/LDA/other mechanism.
What about adding a feature pop3_remap_folders to virtually place *all*
messages spread across different folders inside INBOX, only for the POP3
session, and without impact on the actual folder structure as seen thru
IMAP?
I see some issues though:
- How would SENT and TRASH be handled? These special foldersshouldn't be part of the game.
- What happens if the POP3 client deletes a message, which is thedefault behavior of Outlook and friends? Proposed logic: really delete message if not logged in via IMAP since ($filemtime_of_message - $user_configurable_amount_of_seconds), else gracefully ignore client's delete request. This *could* become a problem if quotas are enabled, but then again it should be the admin's decision to offer this feature to his users.
- Message IDs: Would the above Delete-only-if workaround confusesome mail clients and make them download the same messages over and over?
- Perhaps another way: create a separate POP3 directory inside themailbox, only used by dovecot-pop3. Inside reside symlinks to the actual messages spread across different IMAP folders, which can safely be deleted by a POP3 client and also following the real-delete logic described above.
The benefit of such a virtual folder remapping would be great for systems also using webmail and/or Sieve.
Regards, James
-- jbdovecot@fcgh.net
on 10-3-2008 11:44 AM jbdovecot@fcgh.net spake the following:
Hallo,
is it possible to implement a "flat folder view" for POP3 users?
The problem is that POP3 only knows one folder: INBOX. Now, if a user logs in via POP3, he won't see messages that live outside the INBOX folder - this could be e.g. a *SPAM*-flagged message moved to another folder via Sieve/LDA/other mechanism.
What about adding a feature
pop3_remap_foldersto virtually place *all* messages spread across different folders inside INBOX, only for the POP3 session, and without impact on the actual folder structure as seen thru IMAP?I see some issues though:
How would SENT and TRASH be handled? These special folders shouldn't be part of the game.
What happens if the POP3 client deletes a message, which is the default behavior of Outlook and friends? Proposed logic: really delete message if not logged in via IMAP since ($filemtime_of_message - $user_configurable_amount_of_seconds), else gracefully ignore client's delete request. This *could* become a problem if quotas are enabled, but then again it should be the admin's decision to offer this feature to his users.
Message IDs: Would the above Delete-only-if workaround confuse some mail clients and make them download the same messages over and over?
Perhaps another way: create a separate POP3 directory inside the mailbox, only used by dovecot-pop3. Inside reside symlinks to the actual messages spread across different IMAP folders, which can safely be deleted by a POP3 client and also following the real-delete logic described above.
The benefit of such a virtual folder remapping would be great for systems also using webmail and/or Sieve.
A pop3 user probably wouldn't be using any server side filtering. If you have mostly pop3 users you should be just adding headers or modifying the subject so they can client side filter them.
I don't think there should be any default server side filtering except for either tagging or deleting said flotsam. A user should be technically able to know how and what the filters are and how to use them, and be using IMAP if he wants server side filtering that moves mail around.
Besides what you propose probably violates a few RFC's.
-- MailScanner is like deodorant... You hope everybody uses it, and you notice quickly if they don't!!!!
James wrote:
is it possible to implement a "flat folder view" for POP3 users?
No. If you need folder, use IMAP. If you need Sieve, use IMAP. If you need Sent or Spam folders, use IMAP.
POP3 is limited and it is neither possible nor useful to simulate IMAP behavoir with POP3. That's the reason why IMAP was invented.
Heiko
Heiko Schlichting Freie Universität Berlin heiko@FU-Berlin.DE Zentraleinrichtung für Datenverarbeitung (ZEDAT) Telefon +49 30 838-54327 Fabeckstraße 32 Telefax +49 30 838454327 14195 Berlin
Guten Morgen Heiko,
I think you misunderstood. I'm not after a way of simulating IMAP via POP3, which would certainly violate RFCs. I'm looking for a way to make *all* messages accessible to a POP3 client, regardless a message is inside the INBOX folder or not. To illustrate:
IMAP/Webmail view: # Current POP3 # Intended # implementation # "POP3 view":
- INBOX folder # #
- message a # + message a # + message a
- message b # + message b # + message b
- Spam folder # # + message c
- message c # # + message d
- Work folder # #
- message d # #
- SENT folder # #
- message e # #
Message "e" isn't part of the "POP3 view" as the SENT and the TRASH folders are special. So it would boil down to a virtual folder view a POP3 client gets. Is that possible?
Maybe I didn't correctly chose some technical terms :-)
James
Heiko wrote: James wrote:
is it possible to implement a "flat folder view" for POP3 users?
No. If you need folder, use IMAP. If you need Sieve, use IMAP. If you need Sent or Spam folders, use IMAP.
POP3 is limited and it is neither possible nor useful to simulate IMAP behavoir with POP3. That's the reason why IMAP was invented.
Heiko
Heiko Schlichting Freie Universität Berlin heiko@FU-Berlin.DE Zentraleinrichtung für Datenverarbeitung (ZEDAT) Telefon +49 30 838-54327 Fabeckstraße 32 Telefax +49 30 838454327 14195 Berlin
James Barrante wrote:
Guten Morgen Heiko,
I think you misunderstood. I'm not after a way of simulating IMAP via POP3, which would certainly violate RFCs. I'm looking for a way to make *all* messages accessible to a POP3 client, regardless a message is inside the INBOX folder or not. To illustrate:
IMAP/Webmail view: # Current POP3 # Intended # implementation # "POP3 view":
- INBOX folder # #
- message a # + message a # + message a
- message b # + message b # + message b
- Spam folder # # + message c
- message c # # + message d
- Work folder # #
- message d # #
- SENT folder # #
- message e # #
Message "e" isn't part of the "POP3 view" as the SENT and the TRASH folders are special. So it would boil down to a virtual folder view a POP3 client gets. Is that possible?
just an idea, not sure it would work correctly: create a second account which mailboxes are folders of the "normal" account.
an alternative (not what you want, but may be related), if the user has few folders, create one POP3 account per folder. This would allow a user to see two specific folders if he connects with a "small device".
Hello, James! You wrote to dovecot@dovecot.org on Sat, 4 Oct 2008 04:26:47 +0200:
I think will realise a folder choice at login state: USER username#foldername This implementation is accessible in some servers.
With best regards, Anton Zakatov. E-mail: anton@abn.ru
On Fri, 2008-10-03 at 20:44 +0200, jbdovecot@fcgh.net wrote:
is it possible to implement a "flat folder view" for POP3 users?
v1.2 has virtual mailboxes where you could create a virtual INBOX for POP3 users.
What happens if the POP3 client deletes a message, which is the default behavior of Outlook and friends? Proposed logic: really delete message if not logged in via IMAP since ($filemtime_of_message - $user_configurable_amount_of_seconds), else gracefully ignore client's delete request. This *could* become a problem if quotas are enabled, but then again it should be the admin's decision to offer this feature to his users.
Message IDs: Would the above Delete-only-if workaround confuse some mail clients and make them download the same messages over and over?
Probably.
participants (7)
-
Anton Zakatov
-
Heiko Schlichting
-
James Barrante
-
jbdovecot＠fcgh.net
-
mouss
-
Scott Silva
-
Timo Sirainen