POE::Component::Client::SMTP - Asynchronous mail sending with POE

 # load PoCoClient::SMTP
 use POE::Component::Client::SMTP;
 # spawn a session
 POE::Component::Client::SMTP->send(
     From    => 'foo@baz.com',
     To      => 'john@doe.net',
     Server  =>  'relay.mailer.net',
     SMTP_Success   =>  'callback_event_for_success',
     SMTP_Failure    =>  'callback_event_for_failure',
 );
 # and you are all set ;-)

 # load PoCoClient::SMTP
 use POE::Component::Client::SMTP;
 # spawn a session
 POE::Component::Client::SMTP->send(
     # Email related parameters
     From    => 'foo@baz.com',
     To      => [
                'john@doe.net',
                'andy@zzz.org',
                'peter@z.net',
                'george@g.com',
                ],
     Body    =>  \$email_body,   # here's where your message is stored
     Server  =>  'relay.mailer.net',
     Timeout => 100, # 100 seconds before timeouting
     # POE related parameters
     Alias           => 'pococlsmtpX',
     SMTP_Success    =>  'callback_event_for_success',
     SMTP_Failure    =>  'callback_event_for_failure',
 );
 # and you are all set ;-)

# Copyright (c) 2005 - 2009 George Nistorica
# All rights reserved.
# This program is free software; you can redistribute it and/or
# modify it under the same terms as Perl itself.  See the LICENSE
# file that comes with this distribution for more details.

# 	$Id: SMTP.pm,v 1.25 2009/09/02 08:23:37 UltraDM Exp $

package POE::Component::Client::SMTP;

# TODO:
# * more nice output in debug mode

use warnings;
use strict;

our $VERSION = q{0.22};

use Data::Dumper;
use Carp;
use Socket;
use Symbol qw( gensym );
use POE;
use POE::Wheel::SocketFactory;
use POE::Wheel::ReadWrite;
use POE::Filter::Line;
use POE::Filter::Stream;
use POE::Filter::Transparent::SMTP;

# End of line as specified by SMTP RFC
my $EOL = qq{\015\012};

# an alias to _create currently
# perhaps it could have dual behaviour in the future
sub send {
    _create(@_);
    return 1;
}

# Create session
sub _create {
    my $class      = shift;
    my %parameters = @_;

    # some checking
    croak q{not an object method} if ( ref $class );

    # The actual Object;
    # fill the PoCo parameter from the parameters we got and add the
    # defaults where the parameters are not supplied
    my $self = bless _fill_data( \%parameters ), $class;

    # store the caller
    $self->parameter( q{Caller_Session}, $poe_kernel->get_active_session() );

    # did we sent the callback event back?
    # used so that the poco won't send multiple events for the same
    # SMTP session
    $self->parameter( q{message_sent}, 0 );

    # Spawn the PoCoClient::SMTP session
    POE::Session->create(
        q{object_states} => [
            $self => {
                q{_start}   => q{_pococlsmtp_start},
                q{_stop}    => q{_pococlsmtp_stop},
                q{_default} => q{_pococlsmtp_default},

                # public available events
                q{smtp_shutdown} => q{_pococlsmtp_shutdown},
                q{smtp_progress} => q{_pococlsmtp_progress},

                # internal events SMTP codes and stuff
                q{smtp_send} => q{_pococlsmtp_send},

                # network related
                q{connection_established} => q{_pococlsmtp_conn_est},
                q{connection_error}       => q{_pococlsmtp_conn_err},
                q{smtp_session_input}     => q{_pococlsmtp_input},
                q{smtp_session_error}     => q{_pococlsmtp_error},
                q{smtp_timeout_event}     => q{_smtp_timeout_handler},

                q{_build_commands}        => q{_build_commands},
                q{_build_expected_states} => q{_build_expected_states},

                # return events
                q{return_failure} => q{_pococlsmtp_return_error_event},

                # file slurping
                q{_get_file}               => q{_get_file},
                q{_slurp_file_input_event} => q{_slurp_file_input_event},
                q{_slurp_file_error_event} => q{_slurp_file_error_event},
            },
        ],
    );
    return 1;
}

# EVENT HANDLERS

# event: _start
sub _pococlsmtp_start {
    my ( $kernel, $self ) = @_[ KERNEL, OBJECT ];

    carp q{CURRENT STATE: _pococlsmtp_start} if $self->debug;

    # in case there's no alias, use refcount
    if ( $self->parameter(q{Alias}) ) {
        $kernel->alias_set( $self->parameter(q{Alias}) );
    }
    else {
        $kernel->refcount_increment(
            $kernel->get_active_session()->ID() => __PACKAGE__ );
    }

    # build expected states
    $kernel->yield(q{_build_expected_states});

    return 1;
}

# event: _stop
sub _pococlsmtp_stop {
    my ( $kernel, $self ) = @_[ KERNEL, OBJECT ];
    carp q{CURRENT STATE _pococlsmtp_stop} if $self->debug;
    return 1;
}

# event: _default
sub _pococlsmtp_default {
    my ($self) = $_[OBJECT];
    carp q{CURRENT STATE _pococlsmtp_default} if $self->debug;
    return 1;
}

# this takes care of wheel creation and initial handshake with the SMTP server
# event: smtp_send
sub _pococlsmtp_send {
    my ( $kernel, $self ) = @_[ KERNEL, OBJECT ];
    my ( %options, $wheel, $alarm );

    carp q{CURRENT STATE: _pococlsmtp_send} if $self->debug;

    %options = (
        q{RemoteAddress}  => $self->parameter(q{Server}),
        q{RemotePort}     => $self->parameter(q{Port}),
        q{SocketDomain}   => AF_INET,
        q{SocketType}     => SOCK_STREAM,
        q{SocketProtocol} => q{tcp},
        q{Reuse}          => q{yes},
        q{SuccessEvent}   => q{connection_established},
        q{FailureEvent}   => q{connection_error},
    );

    # set BindAddress and BindPort if any.
    for my $opt ( q{BindAddress}, q{BindPort} ) {
        if ( defined $self->parameter($opt) ) {
            $options{$opt} = $self->parameter($opt);
        }
    }

    # set the alarm for preventing timeouts
    $alarm =
      $kernel->delay_set( q{smtp_timeout_event}, $self->parameter(q{Timeout}) );

    # store the alarm to be used when talking to the SMTP server
    $self->_alarm($alarm);

    $wheel = POE::Wheel::SocketFactory->new( %options, );

    # store the wheel
    $self->store_sf_wheel($wheel);

    return 1;
}

# event: connection_established
# event: SuccessEvent
sub _pococlsmtp_conn_est {
    my ( $kernel, $self, $socket ) = @_[ KERNEL, OBJECT, ARG0 ];
    my ( $wheel, $alarm );

    carp q{CURRENT STATE: _pococlsmtp_conn_est} if $self->debug;

    $wheel = POE::Wheel::ReadWrite->new(
        q{Handle}       => $socket,
        q{InputFilter}  => POE::Filter::Transparent::SMTP->new(),
        q{OutputFilter} => POE::Filter::Transparent::SMTP->new(),
        q{InputEvent}   => q{smtp_session_input},
        q{ErrorEvent}   => q{smtp_session_error},
    );

    # set the alarm for preventing timeouts
    $alarm =
      $kernel->delay_set( q{smtp_timeout_event}, $self->parameter(q{Timeout}) );

    # store the wheel
    $self->store_rw_wheel($wheel);

    # store the alarm; this is used while 'talking' with the SMTP server, during
    # _pococlsmtp_input
    $self->_alarm($alarm);

    return 1;
}

# event: connection_error
# event: FailureEvent
sub _pococlsmtp_conn_err {
    my ( $kernel, $self ) = @_[ KERNEL, OBJECT ];

    carp q{CURRENT STATE: _pococlsmtp_conn_err} if $self->debug;

    # send back to the caller the error which is generated during the
    # connection establishing
    $kernel->yield( q{return_failure},
        { q{POE::Wheel::SocketFactory} => [ @_[ ARG0 .. ARG3 ] ] } );

    return 1;
}

# we've got our connection established, now we're processing input
# event: InputEvent
# event: smtp_session_input
sub _pococlsmtp_input {
    my ( $kernel, $self, $input, $wheel_id ) = @_[ KERNEL, OBJECT, ARG0, ARG1 ];
    my ( $smtp_code, $smtp_string, $to_send );

    carp q{CURRENT STATE: _pococlsmtp_input} if $self->debug;

    # reset alarm
    $kernel->delay_adjust( $self->_alarm, $self->parameter(q{Timeout}), );

    if ( $self->parameter(q{TransactionLog}) ) {

        # add to the transaction log
        $self->_transaction_log( q{<- } . $input );
    }

    # allright, received something in the form XXX text
    if (
        $input =~ /
                                        ^(\d{3})    # first 3 digits
                                        \s+
                                        (.*)$       # SMTP message corresponding to the SMTP code
                                        /xo
        or $input =~ /
			 			 ^(\d{3})
			 			 \s*$ # in case there's no status message  ...
		     		     /xo
      )
    {

        # is the SMTP server letting us know there's a problem?
        ( $smtp_code, $smtp_string ) = ( $1, $2 );
        if ( not defined $smtp_string ) {

            # in case there's no status message from server
            $smtp_string = q{Inserted by PoCoClSMTP: }
              . q{Server didn't sent any status message along with the status code!};
        }
        if ( not defined $smtp_code ) {
            $smtp_code = q{Inserted by PoCoClSMTP: }
              . q{Server didn't replied with a status code as expected!};
        }
        if ( $smtp_code =~ /^(1|2|3)\d{2}$/ ) {

            # we're ok
            # and also stupid, don't know estmp, don't know 1XY codes
            $to_send = $self->command;

            if ( not defined $to_send ) {

                # this is the end of the 'commands' we had stored for sending to
                # the server
                if ( not $self->parameter(q{message_sent}) ) {
                    carp q{Sending SUCCESS event to the caller session}
                      if $self->debug;

                    # send callback only once
                    $kernel->post(
                        $self->parameter(q{Caller_Session}),
                        $self->parameter(q{SMTP_Success}),
                        $self->parameter(q{Context}),
                        $self->_transaction_log(),
                    );
                }

                $self->parameter( q{message_sent}, 1 );
                $self->_smtp_component_destroy;
            }
            else {
                carp qq{PoCoClSMTP TO SEND: "$to_send"} if $self->debug;
                if ( $self->parameter(q{TransactionLog}) ) {
                    $self->_transaction_log( q{-> } . $to_send );
                }
                $self->store_rw_wheel->put($to_send);
            }
        }
        elsif (
            $smtp_code =~ /
                                                  ^(4|5)\d{2}$    # look for error codes (starting with 4 or 5)
                                                                /xo
          )
        {
            carp qq{Server Error! $input } if $self->debug;

            # the server responded with 4XY or 5XY code;
            # while 4XY is temporary failure, 5XY is permanent
            # it's unclear to me whether PoCoClientSMTP should retry in case of
            # 4XY or the user should. In case is PoCoClientSMTP's job, then I
            # should define for how many times and what interval
            $kernel->yield( q{return_failure},
                { q{SMTP_Server_Error} => $input } );
        }
        else {

            # oops! we shouldn't end-up here unless the server is buggy
            carp qq{Error! I don't know the SMTP Code! "$input"}
              if $self->debug;
            $kernel->yield( q{return_failure},
                { q{SMTP_Server_Error} => $input } );
        }
    }
    elsif (
        $input =~ /
                                                # these lines are advertising SMTP capabilities
                                                ^(\d{3})    # 3 digits
                                                \-          # separator
                                                (.*)$       # capability
                                        /xo
      )
    {
        if ( $self->parameter(q{Debug}) > 1 ) {
            carp qq{ESMTP Server capability: "$input"};
        }
    }
    else {
        carp qq{Received unknown string type from SMTP server, "$input"}
          if $self->debug;
        $kernel->yield( q{return_failure}, { q{SMTP_Server_Error} => $input } );
    }

    return 1;
}

# event: smtp_session_error
# event: ErrorEvent
sub _pococlsmtp_error {
    my ( $kernel, $self ) = @_[ KERNEL, OBJECT ];
    carp q{CURRENT STATE: _pococlsmtp_error} if $self->debug;
    $kernel->yield( q{return_failure},
        { q{POE::Wheel::ReadWrite} => [ @_[ ARG0 .. ARG3 ] ] } );
    return 1;
}

# event: smtp_timeout_event
sub _smtp_timeout_handler {
    my ( $kernel, $self ) = @_[ KERNEL, OBJECT ];
    carp q{CURRENT STATE: _smtp_timeout_handler} if $self->debug;
    $kernel->yield( q{return_failure},
        { q{Timeout} => $self->parameter(q{Timeout}) } );
    return 1;
}

# event: return_failure
sub _pococlsmtp_return_error_event {
    my ( $kernel, $self, $arg, $session ) = @_[ KERNEL, OBJECT, ARG0, SESSION ];
    carp q{CURRENT STATE: _pococlsmtp_return_error_event} if $self->debug;
    my $error = $arg;

    my $error_line = q{};
    foreach my $key ( keys %{$error} ) {
        $error_line .= $key . q{: };
        my $value = $error->{$key};
        if ( ref $value eq q{ARRAY} ) {
            $error_line .= join( q{, }, @{$value} );
        }
        else {
            $error_line .= $value;
        }
    }

    # send the callback just once
    if ( not $self->parameter(q{message_sent}) ) {
        carp q{Sending FAIL event to the caller session} if $self->debug;
        $kernel->post(
            $self->parameter(q{Caller_Session}),
            $self->parameter(q{SMTP_Failure}),
            $self->parameter(q{Context}),
            $arg,
            $self->_transaction_log,
            $error_line,
        );
    }
    $self->parameter( q{message_sent}, 1 );
    $self->_smtp_component_destroy;
    return 1;
}

sub _smtp_component_destroy {
    my $self = shift;

    carp q{CURRENT STATE: _smtp_component_destroy} if $self->debug;

    # remove alarms set for the Timeout
    $poe_kernel->alarm_remove_all();

    # in case there's no alias, use refcount
    if ( $self->parameter(q{Alias}) ) {
        $poe_kernel->alias_remove( $self->parameter(q{Alias}) );
    }
    else {
        $poe_kernel->refcount_decrement(
            $poe_kernel->get_active_session()->ID() => __PACKAGE__ );
    }

    # delete all wheels
    $self->delete_rw_wheel;
    $self->delete_sf_wheel;
    $self->delete_file_wheel;

    return 1;
}

# place holder for future closing shutdown of the component
# useful in case the component will be sending multiple messages
# event: smtp_shutdown
sub _pococlsmtp_shutdown {
}

# place holder for future sending back "progress events" in case
# sending multiple messages
# event: smtp_progress
sub _pococlsmtp_progress {
}

# END OF EVENT HANDLERS

# UNDER THE HOOD

# take parameters, do checks on them and fill the object with data
sub _fill_data {
    my $parameters = shift;
    my $smtp_hash;

    # defaults
    my %default = (
        q{To}           => q{root@localhost},
        q{From}         => q{root@localhost},
        q{Body}         => q{},
        q{Server}       => q{localhost},
        q{Port}         => 25,
        q{Timeout}      => 30,
        q{MyHostname}   => q{localhost},
        q{BindAddress}  => undef,
        q{BindPort}     => undef,
        q{Debug}        => 0,
        q{Alias}        => undef,
        q{Context}      => undef,
        q{SMTP_Success} => undef,
        q{SMTP_Failure} => undef,
        q{Auth}         => {
            q{mechanism} => undef,
            q{user}      => undef,
            q{pass}      => undef,
        },
        q{MessageFile}    => undef,
        q{FileHandle}     => undef,
        q{TransactionLog} => undef,
    );

    #check parameters and set them to defaults if they don't exist
    for my $parameter ( keys %default ) {
        if ( exists $parameters->{$parameter} ) {
            $smtp_hash->{q{Parameter}}->{$parameter} =
              $parameters->{$parameter};
        }
        else {
            $smtp_hash->{q{Parameter}}->{$parameter} = $default{$parameter};
        }
    }

    # add supported auth methods
    # for this poco
    $smtp_hash->{q{Auth_Mechanism}} = [q{PLAIN}];

    return $smtp_hash;
}

# accessor/mutator
sub parameter {
    my ( $self, $parameter, $value ) = ( shift, shift, shift );

    croak q{This is an object method only} if ( not ref $self );
    croak q{need a parameter!} if ( not defined $parameter );

    if ( defined $value ) {
        $self->{q{Parameter}}->{qq{$parameter}} = $value;
    }

    return $self->{q{Parameter}}->{qq{$parameter}};
}

# accessor/mutator
# stores and returns the SocketFactory wheel
sub store_sf_wheel {
    my ( $self, $wheel ) = ( shift, shift );
    croak q{not a class method} if ( not ref $self );
    if ( defined $wheel ) {
        $self->{q{Wheel}}->{q{SF}}->{$wheel} = $wheel;
    }
    return $self->{q{Wheel}}->{q{SF}};
}

# if specified which SocketFactory wheel to delete it deletes it;
# if not specified, it deletes ALL SocketFactory wheels
sub delete_sf_wheel {
    my ( $self, $wheel ) = ( shift, shift );
    croak q{not a class method} if ( not ref $self );
    if ( defined $wheel ) {
        return delete $self->{q{Wheel}}->{q{SF}}->{$wheel};
    }
    else {
        my $sf_wheel = delete $self->{q{Wheel}}->{q{SF}};
    }
}

sub store_rw_wheel {
    my ( $self, $wheel ) = ( shift, shift );
    my $ret;

    croak q{not a class method} if ( not ref $self );

    if ( defined $wheel ) {
        $self->{q{Wheel}}->{q{RW}}->{$wheel} = $wheel;
        $ret = $self->{q{Wheel}}->{q{RW}}->{$wheel};
    }
    else {
        foreach my $key ( keys %{ $self->{q{Wheel}}->{q{RW}} } ) {
            $ret = $self->{q{Wheel}}->{q{RW}}->{$key};
            last;
        }
    }

    if ( not defined $ret ) {
        $ret = $self->{q{Wheel}}->{q{RW}};
    }

    return $ret;

}

sub delete_rw_wheel {
    my ( $self, $wheel ) = ( shift, shift );
    croak q{not a class method} if ( not ref $self );
    if ( defined $wheel ) {
        return delete $self->{q{Wheel}}->{$wheel};
    }
    else {
        return delete $self->{q{Wheel}}->{q{RW}};
    }
}

# accessor/mutator
sub store_file_wheel {
    my $self  = shift;
    my $wheel = shift;
    croak 'not a class method' if ( not ref $self );
    if ( defined $wheel ) {
        $self->{'Wheel'}->{'FileWheel'}->{$wheel} = $wheel;
    }
    return $self->{'Wheel'}->{'FileWheel'};
}

sub delete_file_wheel {
    my ( $self, $wheel ) = ( shift, shift );
    croak q{not a class method} if ( not ref $self );
    if ( defined $wheel ) {
        return delete $self->{q{Wheel}}->{q{FileWheel}}->{$wheel};
    }
    else {
        return delete $self->{q{Wheel}}->{q{FileWheel}};
    }
}

# accessor/mutator for the alarm
sub _alarm {
    my ( $self, $alarm ) = ( shift, shift );
    croak q{not a class method} if ( not ref $self );
    if ( defined $alarm ) {
        $self->{q{session_alarm}} = $alarm;
        return $self;
    }
    else {
        return $self->{q{session_alarm}};
    }
}

# return the current expected state
# return value is a list of expected values
sub _state {
    my $self = shift;
    croak q{not a class method} if ( not ref $self );
    return shift @{ $self->{q{State}} };
}

# build the expected list of states for every SMTP command we will be sending
# event: _build_expected_states
sub _build_expected_states {
    my ( $kernel, $self ) = @_[ KERNEL, OBJECT ];
    my ( @states, $rcpt_to );

    croak q{not a class method} if ( not ref $self );

    carp q{CURRENT STATE: _build_expected_states} if $self->debug;

    # initial state, the SMTP server greeting
    push @states, [ 220, 221 ];

    # "ehlo" command
    push @states, [ 250, 251 ];

    # TODO: check if server only supports HELO (is this sane nowadays?)

    if ( defined $self->parameter(q{Auth})->{q{mechanism}} ) {

        # "auth" command
        push @states, [235];
    }

    # "mail from" command
    push @states, [ 250, 251 ], $rcpt_to = \$self->parameter(q{To});

    # "rcpt to" command
    if ( ref( ${$rcpt_to} ) =~ /SCALAR/io ) {
        push @states, [ 250, 251 ];
    }
    elsif ( ref( ${$rcpt_to} ) =~ /ARRAY/io ) {
        for ( 0 .. $#{ ${$rcpt_to} } ) {
            push @states, [ 250, 251 ];
        }
    }
    else {
        push @states, [ 250, 251 ];
    }

    # "data" command:
    push @states, [ 354, ];

    # dot command
    push @states, [ 250, ];

    # "quit" command
    push @states, [ 221, ];

    $self->{q{State}} = @states;

    if (   defined $self->parameter(q{MessageFile})
        or defined $self->parameter(q{FileHandle}) )
    {
        $kernel->yield(q{_get_file});
    }
    else {
        $kernel->yield(q{_build_commands});
    }
    return $self;
}

# event: _get_file
# in case MessageFile is set, slurp the contents of the file into Body
sub _get_file {
    my ( $self, $kernel ) = @_[ OBJECT, KERNEL ];
    my ( $handle, $wheel );
    carp q{CURRENT STATE: _get_file} if $self->debug;

    if ( not defined $self->parameter(q{FileHandle}) ) {
        $handle = _open_file( $self->parameter(q{MessageFile}) );
    }
    else {
        $handle = $self->parameter(q{FileHandle});
    }

    if ( not defined $handle ) {

        # no file handle
        carp q{File not found!} if $self->debug;
        $kernel->yield(
            q{return_failure},
            {
                q{MessageFile_Error} =>
                  [ $self->parameter(q{MessageFile}) . q{ not found!} ],
            },
        );
        return;
    }

    if ( defined $self->parameter(q{Body}) ) {
        $self->parameter( q{Body}, q{} );
    }

    $wheel = POE::Wheel::ReadWrite->new(
        q{Handle}     => $handle,
        q{Filter}     => POE::Filter::Stream->new,
        q{InputEvent} => q{_slurp_file_input_event},
        q{ErrorEvent} => q{_slurp_file_error_event},
    );
    $self->store_file_wheel($wheel);
    return 1;

}

# event: InputEvent
# event: _slurp_file_input_event
sub _slurp_file_input_event {
    my ( $self, $kernel, $input ) = @_[ OBJECT, KERNEL, ARG0 ];
    carp q{CURRENT STATE: _slurp_file_input_event} if $self->debug;
    $self->parameter( q{Body}, $self->parameter(q{Body}) . $input );
    return 1;
}

# event: ErrorEvent
# event: _slurp_file_error_event
sub _slurp_file_error_event {
    my ( $self, $kernel ) = @_[ OBJECT, KERNEL ];
    my ( $operation, $errnum, $errstr, $wheel_id ) = @_[ ARG0 .. ARG3 ];
    carp q{CURRENT STATE: _slurp_file_error_event} if $self->debug;
    if ( $self->debug > 1 ) {
        carp <<"EOER";
Operation: $operation
ERRNUM: $errnum
ERRSTR: $errstr
WHEELID: $wheel_id
EOER
    }
    if ( $errnum == 0 ) {

        # go to the next step, building the commands, now that we have
        # the Body filled with the file contents
        # Escape single dots on a line
        my $filter =
          POE::Filter::Transparent::SMTP->new( q{EscapeSingleInputDot} => 1, );
        my $lines = $self->parameter(q{Body});
        $lines = $filter->get( [$lines] );
        $lines = $filter->put($lines);
        $self->parameter( q{Body}, join( q{}, @{$lines} ) );
        $kernel->yield(q{_build_commands});
    }
    else {

        # we've got an wheel error!
        $kernel->yield(
            q{return_failure},
            {
                q{POE::Wheel::ReadWrite} =>
                  [ $operation, $errnum, $errstr, $wheel_id ]
            }
        );
    }

    return 1;
}

# return the next command
sub command {
    my $self = shift;

    croak q{not a class method} if ( not ref $self );

    return shift @{ $self->{q{Command}} };

}

# build the list of commands
# event: _build_commands
sub _build_commands {
    my ( $kernel, $self, $session ) = @_[ KERNEL, OBJECT, SESSION ];
    my ( @commands, $mechanism, $user, $pass, $rcpt_to, $body );

    croak q{not a class method} if ( not ref $self );

    carp q{CURRENT STATE: _build_commands} if $self->debug;

    $mechanism = $self->parameter('Auth')->{'mechanism'};
    $user      = $self->parameter('Auth')->{'user'};
    $pass      = $self->parameter('Auth')->{'pass'};
    if ( defined $mechanism ) {
        if ( $self->_is_auth_supported_by_poco($mechanism) ) {

            # here we start ESMTP ...
            if ( defined $user and defined $pass ) {
                my $encoded_data =
                  $self->_encode_auth( $mechanism, $user, $pass );
                push @commands, q{EHLO } . $self->parameter(q{MyHostname});
                push @commands, q{AUTH PLAIN } . $encoded_data;
            }
            else {

                # ERROR: user data not complete
                # remove the next event which is smtp_send
                $kernel->state(q{smtp_send});
                $kernel->yield(
                    q{return_failure},
                    {
                        q{Configure} =>
                          q{ERROR: You want AUTH but no USER/PASS given!}
                    }
                );
            }
        }
        else {

            # ERROR: method unsupported by Component!
            # remove the next event which is smtp_send
            $kernel->state(q{smtp_send});
            $kernel->yield(
                q{return_failure},
                {
                    q{Configure} =>
qq{ERROR: Method unsupported by Component version: $VERSION}
                }
            );
        }
    }
    else {
        push @commands, q{HELO } . $self->parameter(q{MyHostname});
    }

    push @commands, q{MAIL FROM: <} . $self->parameter(q{From}) . q{>};
    $rcpt_to = \$self->parameter(q{To});
    if ( ref( ${$rcpt_to} ) =~ /ARRAY/io ) {
        for my $recipient ( @{ ${$rcpt_to} } ) {
            push @commands, q{RCPT TO: <} . $recipient . q{>};
        }
    }
    elsif ( ref( ${$rcpt_to} ) =~ /SCALAR/io ) {
        push @commands, q{RCPT TO: <} . ${ ${$rcpt_to} } . q{>};
    }
    else {

        # no ref, just a scalar ;-)
        push @commands, q{RCPT TO: <} . ${$rcpt_to} . q{>};
    }
    $body = $self->parameter(q{Body});
    if (    not $self->parameter(q{MessageFile})
        and not $self->parameter(q{FileHandle}) )
    {

        # GRR
        # create the body
        # escape single dots on a line
        my $filter =
          POE::Filter::Transparent::SMTP->new( q{EscapeSingleInputDot} => 1, );
        my $data = $filter->get( [$body] );
        $data = $filter->put($data);
        $body = join( q{}, @{$data} );
        $body .= q{.};
    }
    else {
        $body .= qq{$EOL.};
    }

    push @commands, q{DATA}, $body, q{QUIT};

    $self->{q{Command}} = \@commands;
    $kernel->yield(q{smtp_send});

    return $self;
}

sub debug {
    my ( $self, $debug_level ) = ( shift, shift );
    croak q{not a class method} if ( not ref $self );
    if ( defined $debug_level ) {
        $self->parameter(q{Debug}) = $debug_level;
    }
    return $self->parameter(q{Debug});
}

sub _is_auth_supported_by_poco {
    my ( $self, $requested_mehtod ) = ( shift, shift );
    for my $mechanism ( @{ $self->{q{Auth_Mechanism}} } ) {
        if ( uc($requested_mehtod) eq $mechanism ) {
            return 1;
        }
    }
    return 0;
}

# encode the authentication string
sub _encode_auth {
    my ( $self, $mechanism, $user, $pass ) = ( shift, shift, shift, shift );
    my $encoded_data;

    if ( $mechanism eq q{PLAIN} ) {
        eval { require MIME::Base64 };
        if ($@) {
            carp q{You need to install MIME::Base64 to use AUTH PLAIN!};
            $encoded_data = q{I don't have MIME::Base64 installed};
        }
        else {
            $encoded_data =
              MIME::Base64::encode_base64( qq{\0} . $user . qq{\0} . $pass,
                q{} );
        }
    }
    else {
        croak q{ There's a bug in PoCoClSMTP, we really shouldn't get here!};
    }

    return $encoded_data;
}

sub _open_file {
    my $filename = shift;
    my $handle;

    # does file exist and is readable?
    if ( -e $filename and -r $filename ) {
        $handle = gensym();
        open $handle, q{<}, qq{$filename};
    }
    else {
        $handle = undef;
    }

    return $handle;
}

# accessor/mutator
sub _transaction_log {
    my ( $self, $log ) = ( shift, shift );

    croak q{not a class method} if ( not ref $self );

    if ( defined $log ) {
        push @{ $self->{q{transaction_log}} }, $log;
        return $self;
    }
    else {
        return $self->{q{transaction_log}};
    }
}

# END UNDER THE HOOD

1;    # End of POE::Component::Client::SMTP

__END__

# POD BELOW