Namespaces
==========

Dovecot supports fully configurable namespaces. Their original and primary
purpose is to provide Namespace IMAP extension (RFC 2342
[http://www.faqs.org/rfcs/rfc2342.html]) support, which allows giving IMAP
clients hints about where to locate mailboxes and whether they're private,
shared or public. Unfortunately most IMAP clients don't support this extension.

Dovecot namespaces can be used for several other purposes too:

 * Changing the hierarchy separator
 * Providing backwards compatibility when switching from another IMAP server
 * Provides support for <public> [SharedMailboxes.Public.txt] and <shared>
   [SharedMailboxes.Shared.txt] mailboxes
 * Allows having mails in multiple different locations with possibly different
   formats

Configuration
-------------

By default no namespaces are explicitly defined in 'dovecot.conf'. In this
situation Dovecot creates a private namespace automatically. This automatic
namespace creation isn't done when namespaces are defined, so if you intend to
simply add a new namespace, be sure to also add the default private namespace.

There are 3 types of namespaces:

 * private: Typically contains only user's own private mailboxes.
 * shared: Contains other users' <shared mailboxes>
   [SharedMailboxes.Shared.txt].
 * public: Contains <public mailboxes> [SharedMailboxes.Public.txt].

Hierarchy separators
--------------------

Hierarchy separator specifies the character that is used to separate a parent
mailbox from its child mailbox. For example if you have a mailbox "foo" with a
child mailbox "bar", the full path to the child mailbox would be "foo/bar" if
the separator was '/'. With a separator '.' it would be "foo.bar".

IMAP clients, Sieve scripts and many parts of Dovecot configuration use the
configured separator when referring to mailboxes. This means that if you change
the separator, you may break things.

However, changing the separator doesn't change the on-disk "layout separator".
For example:
+-----------------------------+-----------+-----------+---------+---------------------+
| mail_location               | Layout    | Separator | Mailbox | Directory           |
|                             | separator |           | name    |                     |
+-----------------------------+-----------+-----------+---------+---------------------+
| maildir:~/Maildir           | .         | .         | foo.bar | ~/Maildir/.foo.bar/ |
+-----------------------------+-----------+-----------+---------+---------------------+
| maildir:~/Maildir           | .         | /         | foo/bar | ~/Maildir/.foo.bar/ |
+-----------------------------+-----------+-----------+---------+---------------------+
| maildir:~/Maildir:LAYOUT=fs | /         | .         | foo.bar | ~/Maildir/foo/bar/  |
+-----------------------------+-----------+-----------+---------+---------------------+
| maildir:~/Maildir:LAYOUT=fs | /         | /         | foo/bar | ~/Maildir/foo/bar/  |
+-----------------------------+-----------+-----------+---------+---------------------+

Note how the "Separator" changes only the "Mailbox name", but doesn't change
the directory where the mails are stored. The "layout separator" can only be
changed by changing the LAYOUT, which also affects the entire directory
structure.

The layout separator also restricts the mailbox names. For example if the
layout separator is '.', you can't just set separator to '/' and create a
mailbox named "foo.bar". If you need to do this, you can use <listescape>
[Plugins.Listescape.txt] plugin to add escape the mailbox names as necessary.

A commonly used separator is '/'. It probably causes the least amount of
trouble with different IMAP clients. '^' separator is troublesome with
Thunderbird.

You should use the same hierarchy separator for all namespaces. All list=yes
namespaces must use the same separator, but if you find it necessary (e.g. for
backwards compatibility namespaces) you may use different separators for
list=no namespaces.

Namespace settings
------------------

 * prefix: The namespace prefix how it's visible in the NAMESPACE reply (if
   hidden=no) and mailbox list (if list=yes).
 * location: <Mailbox location> [MailLocation.txt]. The default is to use
   'mail_location' setting.
 * inbox: "yes", if this namespace contains the user's INBOX. There is only one
   INBOX, so only one namespace can have inbox=yes.
 * hidden: "yes", if this namespace shouldn't be listed in NAMESPACE reply.
 * list: "yes" (default), if this namespace and its mailboxes should be listed
   by LIST command when the namespace prefix isn't explicitly specified as a
   parameter. "children" means the namespace prefix list listed only if it has
   child mailboxes.
 * subscriptions: "yes" (default) if this namespace should handle its own
   subscriptions. If "no", then the first parent namespace with
   subscriptions=yes will handle it. For example if it's "no" for a namespace
   with prefix=foo/bar/, Dovecot first sees if there's a prefix=foo/ namespace
   with subscriptions=yes and then a namespace with an empty prefix. If neither
   is found, an error is given.

Shared Mailboxes
----------------

See <SharedMailboxes.txt>.

Examples
--------

Mixed mbox and Maildir
----------------------

If you have your INBOX as mbox in '/var/mail/username' and the rest of the
mailboxes in Maildir format under '~/Maildir', you can do this by creating two
namespaces:

---%<-------------------------------------------------------------------------
namespace {
  separator = /
  prefix = "#mbox/"
  location = mbox:~/mail:INBOX=/var/mail/%u
  inbox = yes
  hidden = yes
  list = no
}
namespace {
  separator = /
  prefix =
  location = maildir:~/Maildir
}
---%<-------------------------------------------------------------------------

Without the 'list = no' setting in the first namespace, clients see the "#mbox"
namespace as a non-selectable mailbox named "#mbox" and having child mailboxes
(ie. like a directory). The child mailboxes are all the mbox files in '~/mail'
directory.

Backwards Compatibility: UW-IMAP
--------------------------------

When switching from UW-IMAP and you don't want to give users full access to
filesystem, you can create hidden namespaces which allow users to access their
mails using their existing namespace settings in clients.

---%<-------------------------------------------------------------------------
# default namespace
namespace {
  separator = /
  prefix =
  inbox = yes
}
# for backwards compatibility:
namespace {
  separator = /
  prefix = mail/
  hidden = yes
  list = no
  alias_for =
}
namespace {
  separator = /
  prefix = ~/mail/
  hidden = yes
  list = no
  alias_for =
}
namespace {
  separator = /
  prefix = ~%u/mail/
  hidden = yes
  list = no
  alias_for =
}
---%<-------------------------------------------------------------------------

Backwards Compatibility: Courier IMAP
-------------------------------------

You can continue using the same INBOX. namespace as Courier:

---%<-------------------------------------------------------------------------
namespace {
  separator = .
  prefix = INBOX.
  inbox = yes
}
---%<-------------------------------------------------------------------------

Alternatively you can create the INBOX. as a compatibility name, so old clients
can continue using it while new clients will use the empty prefix namespace:

---%<-------------------------------------------------------------------------
namespace {
  separator = /
  prefix =
  inbox = yes
}

namespace {
  separator = .
  prefix = INBOX.
  inbox = no
  hidden = yes
  list = no
  alias_for =
}
---%<-------------------------------------------------------------------------

The "separator=/" allows the INBOX to have child mailboxes. Otherwise with
"separator=." it wouldn't be possible to know if "INBOX.foo" means INBOX's
"foo" child or the root "foo" mailbox in "INBOX." compatibility namespace. With
"separator=/" the difference is clear with "INBOX/foo" vs. "INBOX.foo".

Per-user Namespace Location From SQL
------------------------------------

You need to give the namespace a name, for example "docs" below:

---%<-------------------------------------------------------------------------
namespace docs {
  type = public
  separator = /
  prefix = Public/
}
---%<-------------------------------------------------------------------------

Then you have an SQL table like:

---%<-------------------------------------------------------------------------
CREATE TABLE Namespaces (
..
  Location varchar(255) NOT NULL,
..
)
---%<-------------------------------------------------------------------------

Now if you want to set the namespace location from the Namespaces table, use
something like:

---%<-------------------------------------------------------------------------
user_query = SELECT Location as 'namespace/docs/location' FROM Namespaces WHERE
..
---%<-------------------------------------------------------------------------

(This file was created from the wiki on 2011-11-16 14:09)