[imp] Deleted messages not moved to trash from client

Thu Apr 9 21:16:16 UTC 2009

Thanks for the clarification.

First of all I'm not a system adminstrator. I've never installed or managed 
an IMAP or IMP service. I have no idea how any of these things actually work 
or what protocols they actually. I'm just a frustrated user trying to get 
answers that my hosting provider doesn't seem to be able to provide. If I'm 
in the wrong place please let me know. However I think I understand now.

Having said all that I'm a 25+ year systems engineer working at the highest 
levels of scientific research. So I'm not stupid either ;-)

So let me summarize: IMAP is a protocol and an IMAP server listens on port 
143 for things that talk IMAP. I'm assuming that an IMAP server also has a 
database (filesystem only probably) where the actual data is stored. IMP is 
a front end to IMAP which provides webmail interface capabilities. So, when 
a client connects to a hosting provider who is offering IMAP on port 143 
then the client is pretty much left on its own to present to the user a 
model that it considers user-friendly. In the case of my iPhone and Webmail 
(when properly configured), when I delete a message using its interface it 
is actually sending a COPY (to Trash mailbox) command, followed by an 
EXPUNGE (from source mailbox) command. Whereas the other clients (Outlook, 
Outlook Express, Windows Mail) are simply sending a MARK AS DELETED command.

Now in the case of Gmail since clients connect to a different port I'm going 
to assume there is an intervening layer they are providing which straightens 
all this mess up and behaves in one consistent way no matter what junk a 
client sends. This is where protocol messages get "translated" if you like.

One person on this list suggests that there is a way to configure IMAP 
client behavior via horde/imp/config/prefs.php. If this is the case, I would 
really like to explore this more. But it also implies that IMP intervenes in 
a generalized way with all IMAP clients that I still don't understand.

Thanks to all for the help.
John

----- Original Message ----- 
From: "Jochen Roderburg" <Roderburg at Uni-Koeln.DE>
To: "E. John Messersmith III" <ejm at ejm3.net>
Cc: <imp at lists.horde.org>
Sent: Thursday, April 09, 2009 2:52 AM
Subject: Re: [imp] Deleted messages not moved to trash from client

> 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
>
>
>