[imp] Deleted messages not moved to trash from client

[Jochen Roderburg]

Zitat von "E. John Messersmith III" <ejm at ejm3.net>:

> Well, I don't know what Gmail is doing either but the iPhone gets it right
> in all cases and all clients get it right when using Gmail. I'm
> not being angry here just very frustrated. I don't know how I can be any
> clearer. It is either a configuration parameter of IMAP or Horde or both.
>
> Webmail - which I think is also part of the Horde project - gets it right
> too! So what is it doing? I go to Mail Options->Deleting and Moving  
> Messages and I simply check the option "When deleting messages, move  
> them to your Trash folder instead of marking them as deleted?" I  
> select a message and click the Delete link. No marking for deletion;  
> no counting; no nothing - just a simple move from one folder to  
> another - everything is still in one Mailbox. So the "delete"  
> command simply gets translated (or is made equivalent to) a "move"  
> to the trash folder command. The client doesn't have to do anything.  
> As long as the server moves the message to the trash folder the new  
> state is simply reflected (updated) in the client. Why is this so  
> difficult to understand? Is there something obvious I'm missing?
>
> So my question remains: given that I have selected the correct  
> Webmail option (and set the corresponding option in all my clients),  
> why is it when a remote IMAP client (Outlook, Outlook Express,  
> Windows Mail) executes a "delete" command and that command is  
> received by the IMAP server is it not translated into a "move" to  
> the trash folder command?

Sorry to say that, but you actually are missing quite a lot.  ;-)
Your cited words seem to indicate that you totally misunderstand how  
the IMAP functions work.
There is no such such thing as a simple "delete command", nothing gets  
translated on the server site, in fact the concept of a "trash folder"  
is totally unknown to the IMAP protocol and on IMAP servers.
All that "trash folder magic" is a thing that the various clients  
handle on their own, be it native Windows Clients or Webmail-Clients  
like IMP. And when you want several clients to behave the same way,  
you have to configure all of them individually. And if they don't  
support your preferred options, you're out of luck.

Some more technical details:

Admittedly, the deletion of mail messages on an IMAP server is  
somewhat unusual. It is a two-step process, first you "mark messages  
as deleted" and then you "expunge" them.

About step 1: Each mail message on the server has a few flags or marks  
which can be read and written by the clients. One of these flags is  
the "delete flag". And the process of setting this delete flag is what  
commonly is described by the phrase "marking as deleted". Such marked  
messages are still on the server and can be used in every other way.  
How they are presented to the human reader depends on the used client.

About step 2: The "expunge" command is given for a whole mail folder  
and "really" deletes all messages which were previously "marked as  
deleted".

This "IMAP native" mail deletion technique should normally be  
available as one option in all IMAP mail clients.

Now to the "trash folders", this is something completely different.  
Such a folder has no special meaning on the server side, it is just an  
IMAP folder like you can have others. It is only used by the client  
for a special purpose. When you have set appropriate client options,  
then the clients moves "deleted mails" to this folder and does not use  
the above described IMAP deletion.
Actually this mail-move is also not a totally simple process, as there  
is no native "move command" in the IMAP protocol, only a "copy  
command". So with every move (including the moves to the trash) the  
client has to copy the mail to the destination folders and delete it  
in the source afterwards (e.g. with the IMAP delete functions again).

Hope these explanations helped a little to clear up the confusions.   ;-)

Best regards,

Jochen Roderburg
RRZK
University of Cologne
Robert-Koch-Str. 10                    Tel.:   +49-221/478-7024
D-50931 Koeln                          E-Mail: Roderburg at Uni-Koeln.DE
Germany