MBOX-Line: From tss at iki.fi  Wed Jun 27 10:45:01 2007
To: imap-protocol@u.washington.edu
From: Timo Sirainen <tss@iki.fi>
Date: Fri Jun  8 12:34:40 2018
Subject: [Imap-protocol] Namespace separators
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Message-ID: <1182966301.3768.383.camel@hurina>

On Wed, 2007-06-27 at 09:31 -0700, Mark Crispin wrote:
> Here's what you really missed, if the client does not implement NAMESPACE, 
> the same thing happens: you have a server which, for no apparent reason, 
> changes hierarchy semantics in a non-deterministic fashion!

OK, I guess that makes some sense then if the client allows user to
request listing mailboxes under some name instead of finding them out
itself.

> >> Does your server list all other users' mailboxes with that command (since
> >> after all a user may have a public access mailbox)?  Why not?
> > I was actually going to make it do that, once support for shared
> > mailboxes is finished.
> 
> Any server that automatically lists all other users' mailboxes by default 
> has huge privacy problem.

Not by default. I meant it lists all mailboxes where the mailbox owner
has given permission with ACLs (so filesystem permissions won't be
enough).

> > I've understood that many commonly used clients ignore namespaces and
> > only show what is visible with LIST "" %, so I'd want to keep it
> > possible to list contents of all namespaces with it.
> 
> I am trying to tell you that that is NOT a very good idea; and this is 
> from real-world experience.
> 
> If you do this, you are going to have a huge set of mailboxes listed, and 
> many users will react with "what is all this junk in my account, I need to 
> delete it."

I guess this all depends on what kinds of namespaces you have. Having a #news. namespace listed using LIST is bad, but I think having "shared mailboxes" namespace visible with LIST isn't.

Actually it looks like Cyrus is doing exactly what I was going to:

1 namespace
* NAMESPACE (("" "/")) (("Other Users/" "/")) (("Shared Folders/" "/"))
1 OK Completed
2 list "" *
* LIST (\Noinferiors) "/" "INBOX"
* LIST (\HasNoChildren) "/" "Other Users/foo/support"
2 OK Completed (0.000 secs 10 calls)

There you have a LIST that lists multiple namespaces. Do you consider
this bad as well?

> This happens with stupid clients that implement NAMESPACE and then proceed 
> to list all of those.  The user complaints are continuous and regular: 
> they want to know how to delete these junk names from their account.

I've actually no idea how I would implement NAMESPACE support for
clients in a way you consider good.
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