NAME

NAME
Net::IMAP::Server - A single-threaded multiplexing IMAP server
implementation, using Net::Server::Coro.

SYNOPSIS
use Net::IMAP::Server;
Net::IMAP::Server->new(
port => 193,
ssl_port => 993,
auth_class => "Your::Auth::Class",
model_class => "Your::Model::Class",
user => "nobody",
group => "nobody",
)->run;

DESCRIPTION
This model provides a complete implementation of the "RFC 3501"
specification, along with several IMAP4rev1 extensions. It provides
separation of the mailbox and message store from the client interaction
loop.

Note that, following RFC suggestions, login is not allowed except under
a either SSL or TLS. Thus, you are required to have a certs/ directory
under the current working directory, containing files server-cert.pem
and "server-key.pem". Failure to do so will cause the server to fail to
start. Note that if the default paths suit your needs, you can specify
different ones using the "server_cert" and "server_key" arguments to
"new".

INTERFACE
The primary method of using this module is to supply your own model and
auth classes, which inherit from Net::IMAP::Server::DefaultModel and
Net::IMAP::Server::DefaultAuth. This allows you to back your messages
from arbitrary data sources, or provide your own authorization backend.
For the most part, the implementation of the IMAP components should be
opaque.

METHODS
new PARAMHASH
Creates a new IMAP server object. This doesn't even bind to the sockets;
it merely initializes the object. It will "die" if it cannot find the
appropriate certificate files. Valid arguments to "new" include:

port
The port to bind to. Defaults to port 1430.

ssl_port
The port to open an SSL listener on; by default, this is disabled,
and any true value enables it.

auth_class
The name of the class which implements authentication. This must be
a subclass of Net::IMAP::Server::DefaultAuth.

model_class
The name of the class which implements the model backend. This must
be a subclass of Net::IMAP::Server::DefaultModel.

connection_class
On rare occasions, you may wish to subclass the connection class;
this class must be a subclass of Net::IMAP::Server::Connection.

poll_every
How often the current mailbox should be polled, in seconds; defaults
to 0, which means it will be polled after every client command.

unauth_commands
The number of commands before unauthenticated users are
disconnected. The default is 10; set to zero to disable.

unauth_idle
How long, in seconds, to wait before disconnecting idle connections
which have not authenticated yet. The default is 5 minutes; set to
zero to disable (which is not advised).

auth_idle
How long, in seconds, to wait before disconnecting authenticated
connections. By RFC specification, this must be longer than 30
minutes. The default is an hour; set to zero to disable.

server_cert
Path to the SSL certificate that the server should use. This can be
either a relative or absolute path.

server_key
Path to the SSL certificate key that the server should use. This can
be either a relative or absolute path.

It also accepts the following Net::Server arguments -- see its
documentation for details on their use.

"log_level" in Net::Server
"log_file" in Net::Server
"syslog_logsock" in Net::Server
"syslog_ident" in Net::Server
"syslog_logopt" in Net::Server
"syslog_facility" in Net::Server
"pid_file" in Net::Server
"chroot" in Net::Server
"user" in Net::Server
"group" in Net::Server
"reverse_lookups" in Net::Server
"allow" in Net::Server
"deny" in Net::Server
"cidr_allow" in Net::Server
"cidr_deny" in Net::Server

run
Starts the server; this method shouldn't be expected to return. Within
this method, $Net::IMAP::Server::Server is set to the object that this
was called on; thus, all IMAP objects have a way of referring to the
server -- and though "connection", whatever parts of the IMAP internals
they need.

Any arguments are passed through to "run" in Net::Server.

process_request
Accepts a client connection; this method is needed for the Net::Server
infrastructure.

DESTROY
On destruction, ensure that we close all client connections and
listening sockets.

connections
Returns an arrayref of Net::IMAP::Server::Connection objects which are
currently connected to the server.

connection
Returns the currently active Net::IMAP::Server::Connection object, if
there is one. This is determined by examining the current coroutine.

concurrent_mailbox_connections [MAILBOX]
This can be called as either a class method or an instance method; it
returns the set of connections which are concurrently connected to the
given mailbox object (which defaults to the current connection's
selected mailbox)

concurrent_user_connections [USER]
This can be called as either a class method or an instance method; it
returns the set of connections whose "user" in
Net::IMAP::Server::DefaultAuth is the same as the given USER (which
defaults to the current connection's user)

capability
Returns the "CAPABILITY" string for the server. This string my be
modified by the connection before being sent to the client (see
"capability" in Net::IMAP::Server::Connection).

id
Returns a hash of properties to be conveyed to the client, should they
ask the server's identity.

add_command NAME => PACKAGE
Adds the given command "NAME" to the server's list of known commands.
"PACKAGE" should be the name of a class which inherits from
Net::IMAP::Server::Command.

log SEVERITY, MESSAGE
By default, defers to "log" in Net::Server, which outputs to syslog, a
logfile, or STDERR, depending how it was configured. Net::Server's
default is to print to STDERR. If you have custom logging needs,
override this method, or "write_to_log_hook" in Net::Server.

Object model
An ASCII model of the relationship between objects is below. In it,
single lines represent scalar values, and lines made of other characters
denote array references or relations.

+----------------------------------------------+
| |
| Server |
| |
+1-----2---------------------------------------+
# | ^ ^ ^ ^
# | | | | |
# v | | | |
# +--------1-------+ | +------1------+ |
###>| Connection |<------2 Command | |
# +--4-----3------2+ | +-------------+ |
,-#------' | `--------------. |
| # v | v |
| # +----------------+ | +-------------+ |
| # | Model 2------>| Auth | |
| # +--------1-------+ | +-------------+ |
| # `---------------------------------.
| # | | |
| # ,---' ,---' |
| # +--------------1-+ +-----------1-+ |
| ###>| Connection |<------2 Command | |
| +--4-5---3------2+ +-------------+ |
| ,------' * | `--------------. |
| | ******** v v |
| | * +----------------+ +-------------+ |
| | * | Model 2------>| Auth | |
| | * +--------1-------+ +-------------+ |
| | * | |
| | * | ,------------------------------'
| | * | | ^ SERVER
.|.|.*..........|..|................................
| | * | | v MODEL
| | * v v
| '-*---->+-------------+<------------.
'---*---->| Mailbox |<----------. |
* +-1------2-3--+<----. | |
* @ ^ $ % | | |
* @ | $$$$>+-----1---+ | |
* @ | $ % | | | |
* @ | $ %%>| Message | | |
* @ | $ % | | | |
********@***|******>+---------+ | |
* @ | $ % | |
* @ | $$$$>+---------+ | |
* @ | % | | | |
* @ | %%>| Message 1-' |
* @ | | | |
********@***|******>+---------+ |
* @ | |
* @ | +---------+ |
* @ | | Message 1---'
********@***|******>+---------+
@ |
@ +4----------+
@@>| Mailbox |
+-----------+

The top half consists of the parts which implement the IMAP protocol
itself; the bottom contains the models for the backing store. Note that,
for the most part, the backing store is unaware of the framework of the
server itself.

Each model has references to others, as follows:

Server
Contains references to the set of "connections" (1). It also has a
sense of the *current* "connection" (2), based on the active Coro
thread.

Connection
Connections hold a reference to their "server" (1). If the
connection has authenticated, they hold a reference to the "auth"
object (2), and to their "model" (3). If a mailbox is "selected"
(4), they hold a pointer to that, as well. Infrequently, the
connection will need to temporarily store references to the set of
"temporary_messages" (5) which have been expunged in other
connections, but we have been unable to notify this connection of.

Command
Commands store their "server" (1) and "connection" (2).

Model
Models store a reference to the "root" (1) of their mailbox tree, as
well as to the "auth" (2) which gives them access to such.

Mailbox
Mailboxes store a list of "children" mailboxes (1), and "messages"
(2) contained within them, which are stored in sequence order. They
also contain a hash of "uids" (3) for fast UID retrieval of
messages. If they are not the root mailbox, they also store a
reference to their "parent" mailbox (4).

Message
Messages store the "mailbox" (1) in which they are contained.

DEPENDENCIES
Coro, Net::Server::Coro

BUGS AND LIMITATIONS
No bugs have been reported.

Please report any bugs or feature requests to
"[email protected]", or through the web interface at
<http://rt.cpan.org>.

A low-traffic mailing list exists for discussion on how to (ab)use this
module, at
<http://lists.bestpractical.com/cgi-bin/mailman/listinfo/net-imap-server
>.

AUTHOR
Alex Vandiver "<[email protected]>"

LICENCE AND COPYRIGHT
Copyright (c) 2010, Best Practical Solutions, LLC. All rights reserved.

This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. See perlartistic.

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