[Dovecot] . (dot) in maildir folder names

[Timo Sirainen]

On 25.5.2013, at 1.46, Christoph Anton Mitterer <calestyo at scientia.net> wrote:

> On Sat, 2013-05-25 at 01:19 +0300, Timo Sirainen wrote:
>> That is pretty much standard IMAP mUTF-7. Wonder why that's not
>> mentioned in there.
>> But yeah, looks like it also suggests encoding the '.' and '/' using
>> the mUTF-7 format. That is forbidden by IMAP. So having such names in
>> the maildir and serving them to IMAP clients would actually violate
>> the IMAP protocol.
> I see... so what's the best / most standards compliant way of enabling
> all possible folder names now? Using that plugin?

IMAP protocol requires that one character is reserved for being hierarchy separator. There's no way around that. But with listescape plugin you can use any other character.

> I mean I do not quite understand what happens when I use the plugin... 
> so as far as I understood you know IMAP itself already has an encoding
> way... i.e. the client already sends mUTF-7 encoded foldernames to
> dovecot, and dovecot simply passes this through and creates these as
> file names, right?
> 
> When I use the list encode plugin... will it then \NN encode the
> (possibly already mUTF-7 encoded) string... to also allow things like
> "." and "/"?
> So the client will never see any \NN encoding as this is done purely
> dovecot internally?

Right. It encodes those chars that can't be used in filesystem, but can be used in IMAP protocol. With Maildir the separator is always '.' in the filesystem, but it can be something else visible to IMAP clients, which allows using '.' in IMAP protocol but not in filesystem unescaped.