=head1 NAME

Mail::Transport::IMAP4 - proxy to Mail::IMAPClient

=head1 INHERITANCE

 Mail::Transport::IMAP4
   is a Mail::Transport::Receive
   is a Mail::Transport
   is a Mail::Reporter

=head1 SYNOPSIS

 my $imap = Mail::Transport::IMAP4->new(...);
 my $message = $imap->receive($id);
 $imap->send($message);

=head1 DESCRIPTION

The IMAP4 protocol is quite complicated: it is feature rich and allows
verious asynchronous actions.  The main document describing IMAP is
rfc3501 (which obsoleted the original specification of protocol 4r1
in rfc2060 in March 2003).

This package, as part of MailBox, does not implement the actual
protocol itself but uses Mail::IMAPClient to do the work. The task
for this package is to hide as many differences between that module's
interface and the common MailBox folder types.  Multiple
L<Mail::Box::IMAP4|Mail::Box::IMAP4> folders can share one L<Mail::Transport::IMAP4|Mail::Transport::IMAP4>
connection.

The Mail::IMAPClient module is the best IMAP4 implementation for
Perl5, but is not maintained.  There are many known problems with the
module, and solving those is outside the scope of MailBox.  See
F<http://rt.cpan.org/Public/Dist/Display.html?Name=Mail-IMAPClient>
for all the reported bugs.

=head1 METHODS

$obj-E<gt>B<url>

=over 4

Represent this imap4 connection as URL.

=back

=head2 Constructors

Mail::Transport::IMAP4-E<gt>B<new>(OPTIONS)

=over 4

Create the IMAP connection to the server.  IMAP servers can handle
multiple folders for a single user, which means that connections
may get shared.  This is sharing is hidden for the user.

When an C<imap_client> is specified, then the options C<hostname>,
C<port>, C<username>, and C<password> are extracted from it.

 Option      --Defined in     --Default
 authenticate                   'AUTO'
 domain                         <server_name>
 executable    Mail::Transport  undef
 hostname      Mail::Transport  'localhost'
 imap_client                    Mail::IMAPClient
 interval      Mail::Transport  30
 log           Mail::Reporter   'WARNINGS'
 password      Mail::Transport  undef
 port          Mail::Transport  143
 proxy         Mail::Transport  undef
 retry         Mail::Transport  <false>
 timeout       Mail::Transport  120
 trace         Mail::Reporter   'WARNINGS'
 username      Mail::Transport  undef
 via           Mail::Transport  'imap'

. authenticate => TYPE|ARRAY-OF-TYPES

=over 4

Authenthication method to L<login()|Mail::Transport::IMAP4/"Protocol [internals]">, which will be passed to
L<Mail::IMAPClient> method authenticate().  See the latter method for
the available types.

=back

. domain => WINDOWS_DOMAIN

=over 4

Used for NTLM authentication.

=back

. executable => FILENAME

. hostname => HOSTNAME|ARRAY-OF-HOSTNAMES

. imap_client => OBJECT|CLASS

=over 4

When an OBJECT is supplied, that client will be used for the implementation
of the IMAP4 protocol. Information about server and such are extracted from
the OBJECT to have the accessors to produce correct results. The OBJECT
shall be a L<Mail::IMAPClient|Mail::IMAPClient>.

When a CLASS is given, an object of that type is created for you.  The created
object can be retreived via L<imapClient()|Mail::Transport::IMAP4/"Protocol [internals]">, and than configured as
defined by L<Mail::IMAPClient|Mail::IMAPClient>.

=back

. interval => SECONDS

. log => LEVEL

. password => STRING

. port => INTEGER

. proxy => PATH

. retry => NUMBER|undef

. timeout => SECONDS

. trace => LEVEL

. username => STRING

. via => CLASS|NAME

=back

=head2 Receiving mail

$obj-E<gt>B<receive>([UNIQUE-MESSAGE-ID])

=over 4

See L<Mail::Transport::Receive/"Receiving mail">

=back

=head2 Server connection

$obj-E<gt>B<findBinary>(NAME [, DIRECTORIES])

=over 4

See L<Mail::Transport/"Server connection">

=back

$obj-E<gt>B<remoteHost>

=over 4

See L<Mail::Transport/"Server connection">

=back

$obj-E<gt>B<retry>

=over 4

See L<Mail::Transport/"Server connection">

=back

=head2 Attributes

$obj-E<gt>B<authentication>(['AUTO'|TYPE|LIST-OF-TYPES])

=over 4

Returned is a list of pairs (ref arrays) each describing one possible
way to contact the server. Each pair contains a mechanism name and
a challange callback (which may be C<undef>).

The settings are used by L<login()|Mail::Transport::IMAP4/"Protocol [internals]"> to get server access.  The initial
value origins from L<new(authenticate)|Mail::Transport::IMAP4/"METHODS">, but may be changed later.

Available basic TYPES are C<CRAM-MD5>, C<NTLM>, and C<PLAIN>.  With
C<AUTO>, all available types will be tried.  When the Authen::NTLM
is not installed, the C<NTLM> option will silently be skipped.  Be warned
that, because of C<PLAIN>, erroneous username/password combinations will
be passed readible as last attempt!

The C<NTLM> authentication requires Authen::NTLM to be installed.  Other
methods may be added later.  Besides, you may also specify a CODE
reference which implements some authentication.

An ARRAY as TYPE can be used to specify both mechanism as callback.  When
no array is used, callback of the pair is set to C<undef>.  See
L<Mail::IMAPClient/authenticate> for the gory details.

example: 

 $transporter->authentication('CRAM-MD5', [MY_AUTH => \&c], 'PLAIN');

 foreach my $pair ($transporter->authentication)
 {   my ($mechanism, $challange) = @$pair;
     ...
 }

=back

$obj-E<gt>B<domain>([DOMAIN])

=over 4

Used in NTLM authentication to define the Windows domain which is
accessed.  Initially set by L<new(domain)|Mail::Transport::IMAP4/"METHODS"> and defaults to the
server's name.

=back

=head2 Exchanging Information

=head2 Protocol [internals]

The follow methods handle protocol internals, and should not be used
by a normal user of this class.

$obj-E<gt>B<appendMessage>(MESSAGE, FOLDERNAME)

=over 4

Write the message to the server.

=back

$obj-E<gt>B<createFolder>(NAME)

=over 4

Add a folder.

=back

$obj-E<gt>B<createImapClient>(CLASS)

=over 4

Create an object of CLASS, which extends L<Mail::IMAPClient>.

=back

$obj-E<gt>B<currentFolder>([FOLDERNAME])

=over 4

Be sure that the specific FOLDER is the current one selected.  If the
folder is already selected, no IMAP traffic will be produced.

The boolean return value indicates whether the folder is selectable. It
will return undef if it does not exist.

=back

$obj-E<gt>B<deleteFolder>(NAME)

=over 4

Remove one folder.

=back

$obj-E<gt>B<destroyDeleted>

=over 4

Command the server to delete for real all messages which are flagged to
be deleted.

=back

$obj-E<gt>B<fetch>(ARRAY-OF-MESSAGES, INFO)

=over 4

Get some INFO about the MESSAGES from the server.  The specified messages
shall extend L<Mail::Box::Net::Message|Mail::Box::Net::Message>, Returned is a list
of hashes, each info about one result.  The contents of the hash
differs per INFO, but at least a C<message> field will be present, to
relate to the message in question.

The right folder should be selected before this method is called. When
the connection was lost, C<undef> is returned.  Without any
messages, and empty array is returned.  The retrieval is done by
L<Mail::IMAPClient|Mail::IMAPClient> method C<fetch()>, which is then
parsed.

=back

$obj-E<gt>B<flagsToLabels>(WHAT|FLAGS)

Mail::Transport::IMAP4-E<gt>B<flagsToLabels>(WHAT|FLAGS)

=over 4

In SCALAR context, a hash with labels is returned.  In LIST context, pairs
are returned.

The WHAT parameter can be C<'SET'>, C<'CLEAR'>, or C<'REPLACE'>.  With the
latter, all standard imap flags do not appear in the list will be ignored:
their value may either by set or cleared.  See L<getFlags()|Mail::Transport::IMAP4/"Protocol [internals]">

Unknown flags in LIST are stripped from their backslash and lower-cased.
For instance, '\SomeWeirdFlag' will become `someweirdflag => 1'.

example: translating IMAP4 flags into MailBox flags

 my @flags  = ('\Seen', '\Flagged');
 my $labels = Mail::Transport::IMAP4->flags2labels(SET => @flags);

=back

$obj-E<gt>B<folders>([FOLDERNAME])

=over 4

Returns a list of folder names which are sub-folders of the specified
FOLDERNAME.  Without FOLDERNAME, the top-level foldernames are returned.

=back

$obj-E<gt>B<getFields>(UID, NAME, [NAME, ...])

=over 4

Get the records with the specified NAMES from the header.  The header
fields are returned as list of L<Mail::Message::Field::Fast|Mail::Message::Field::Fast> objects.
When the name is C<ALL>, the whole header is returned.

=back

$obj-E<gt>B<getFlags>(FOLDER, ID)

=over 4

Returns the values of all flags which are related to the message with the
specified ID.  These flags are translated into the names which are
standard for the MailBox suite.

A HASH is returned.  Names which do not appear will also provide
a value in the returned: the negative for the value is it was present.

=back

$obj-E<gt>B<getMessageAsString>(MESSAGE|UID)

=over 4

Returns the whole text of the specified message: the head and the body.

=back

$obj-E<gt>B<ids>

=over 4

Returns a list of UIDs which are defined by the IMAP server.

=back

$obj-E<gt>B<imapClient>

=over 4

Returns the object which implements the IMAP4 protocol, an instance
of a Mail::IMAPClient, which is logged-in and ready to use.

If the contact to the server was still present or could be established,
an Mail::IMAPClient object is returned.  Else, C<undef> is returned and
no further actions should be tried on the object.

=back

$obj-E<gt>B<labelsToFlags>(HASH|PAIRS)

Mail::Transport::IMAP4-E<gt>B<labelsToFlags>(HASH|PAIRS)

=over 4

Convert MailBox labels into IMAP flags.  Returned is a string.  Unsupported
labels are ignored.

=back

$obj-E<gt>B<listFlags>

=over 4

Returns all predefined flags as list.

=back

$obj-E<gt>B<login>

=over 4

Establish a new connection to the IMAP4 server, using username and password.

=back

$obj-E<gt>B<setFlags>(ID, LABEL, VALUE, [LABEL, VALUE], ...)

=over 4

Change the flags on the message which are represented by the label.  The
value which can be related to the label will be lost, because IMAP only
defines a boolean value, where MailBox labels can contain strings.

Returned is a list of LABEL=>VALUE pairs which could not be send to
the IMAP server.  These values may be cached in a different way.

=back

=head2 Error handling

$obj-E<gt>B<AUTOLOAD>

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<addReport>(OBJECT)

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<defaultTrace>([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])

Mail::Transport::IMAP4-E<gt>B<defaultTrace>([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<errors>

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<log>([LEVEL [,STRINGS]])

Mail::Transport::IMAP4-E<gt>B<log>([LEVEL [,STRINGS]])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<logPriority>(LEVEL)

Mail::Transport::IMAP4-E<gt>B<logPriority>(LEVEL)

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<logSettings>

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<notImplemented>

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<report>([LEVEL])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<reportAll>([LEVEL])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<trace>([LEVEL])

=over 4

See L<Mail::Reporter/"Error handling">

=back

$obj-E<gt>B<warnings>

=over 4

See L<Mail::Reporter/"Error handling">

=back

=head2 Cleanup

$obj-E<gt>B<DESTROY>

=over 4

The connection is cleanly terminated when the program is
terminated.

=back

$obj-E<gt>B<inGlobalDestruction>

=over 4

See L<Mail::Reporter/"Cleanup">

=back

=head1 DIAGNOSTICS

Error: Cannot connect to $host:$port for IMAP4: $!

=over 4

=back

Error: IMAP cannot connect to $host: $@

=over 4

=back

Notice: IMAP4 authenication $mechanism to $host:$port successful

=over 4

=back

Error: IMAP4 requires a username and password

=over 4

=back

Error: IMAP4 username $username requires a password

=over 4

=back

Error: Package $package does not implement $method.

=over 4

Fatal error: the specific package (or one of its superclasses) does not
implement this method where it should. This message means that some other
related classes do implement this method however the class at hand does
not.  Probably you should investigate this and probably inform the author
of the package.

=back

=head1 SEE ALSO

This module is part of Mail-Box distribution version 2.073,
built on July 19, 2007. Website: F<http://perl.overmeer.net/mailbox/>

=head1 LICENSE

Copyrights 2001-2007 by Mark Overmeer. For other contributors see ChangeLog.

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See F<http://www.perl.com/perl/misc/Artistic.html>

