NAME

    POE::Component::Server::NNTP - A POE component that provides NNTP
    server functionality.

VERSION

    version 1.06

SYNOPSIS

      use strict;
      use POE qw(Component::Server::NNTP);

      my %groups;

      while(<DATA>) {
        chomp;
        push @{ $groups{'perl.cpan.testers'}->{'<perl.cpan.testers-381062@nntp.perl.org>'} }, $_;
      }

      my $nntpd = POE::Component::Server::NNTP->spawn(
                    alias   => 'nntpd',
                    posting => 0,
                    port    => 10119,
      );

      POE::Session->create(
        package_states => [
            'main' => [ qw(
                            _start
                            nntpd_connection
                            nntpd_disconnected
                            nntpd_cmd_post
                            nntpd_cmd_ihave
                            nntpd_cmd_slave
                            nntpd_cmd_newnews
                            nntpd_cmd_newgroups
                            nntpd_cmd_list
                            nntpd_cmd_group
                            nntpd_cmd_article
            ) ],
        ],
        options => { trace => 0 },
      );

      $poe_kernel->run();
      exit 0;

      sub _start {
        my ($kernel,$heap) = @_[KERNEL,HEAP];
        $heap->{clients} = { };
        $kernel->post( 'nntpd', 'register', 'all' );
        return;
      }

      sub nntpd_connection {
        my ($kernel,$heap,$client_id) = @_[KERNEL,HEAP,ARG0];
        $heap->{clients}->{ $client_id } = { };
        return;
      }

      sub nntpd_disconnected {
        my ($kernel,$heap,$client_id) = @_[KERNEL,HEAP,ARG0];
        delete $heap->{clients}->{ $client_id };
        return;
      }

      sub nntpd_cmd_slave {
        my ($kernel,$sender,$client_id) = @_[KERNEL,SENDER,ARG0];
        $kernel->post( $sender, 'send_to_client', $client_id, '202 slave status noted' );
        return;
      }

      sub nntpd_cmd_post {
        my ($kernel,$sender,$client_id) = @_[KERNEL,SENDER,ARG0];
        $kernel->post( $sender, 'send_to_client', $client_id, '440 posting not allowed' );
        return;
      }

      sub nntpd_cmd_ihave {
        my ($kernel,$sender,$client_id) = @_[KERNEL,SENDER,ARG0];
        $kernel->post( $sender, 'send_to_client', $client_id, '435 article not wanted' );
        return;
      }

      sub nntpd_cmd_newnews {
        my ($kernel,$sender,$client_id) = @_[KERNEL,SENDER,ARG0];
        $kernel->post( $sender, 'send_to_client', $client_id, '230 list of new articles follows' );
        $kernel->post( $sender, 'send_to_client', $client_id, '.' );
        return;
      }

      sub nntpd_cmd_newgroups {
        my ($kernel,$sender,$client_id) = @_[KERNEL,SENDER,ARG0];
        $kernel->post( $sender, 'send_to_client', $client_id, '231 list of new newsgroups follows' );
        $kernel->post( $sender, 'send_to_client', $client_id, '.' );
        return;
      }

      sub nntpd_cmd_list {
        my ($kernel,$sender,$client_id) = @_[KERNEL,SENDER,ARG0];
        $kernel->post( $sender, 'send_to_client', $client_id, '215 list of newsgroups follows' );
        foreach my $group ( keys %groups ) {
            my $reply = join ' ', $group, scalar keys %{ $groups{$group} }, 1, 'n';
            $kernel->post( $sender, 'send_to_client', $client_id, $reply );
        }
        $kernel->post( $sender, 'send_to_client', $client_id, '.' );
        return;
      }

      sub nntpd_cmd_group {
        my ($kernel,$sender,$client_id,$group) = @_[KERNEL,SENDER,ARG0,ARG1];
        unless ( $group or exists $groups{lc $group} ) {
           $kernel->post( $sender, 'send_to_client', $client_id, '411 no such news group' );
           return;
        }
        $group = lc $group;
        $kernel->post( $sender, 'send_to_client', $client_id, "211 1 1 1 $group selected" );
        $_[HEAP]->{clients}->{ $client_id } = { group => $group };
        return;
      }

      sub nntpd_cmd_article {
        my ($kernel,$sender,$client_id,$article) = @_[KERNEL,SENDER,ARG0,ARG1];
        my $group = 'perl.cpan.testers';
        if ( !$article and !defined $_[HEAP]->{clients}->{ $client_id}->{group} ) {
           $kernel->post( $sender, 'send_to_client', $client_id, '412 no newsgroup selected' );
           return;
        }
        $article = 1 unless $article;
        if ( $article !~ /^<.*>$/ and $article ne '1' ) {
           $kernel->post( $sender, 'send_to_client', $client_id, '423 no such article number' );
           return;
        }
        if ( $article =~ /^<.*>$/ and !defined $groups{$group}->{$article} ) {
           $kernel->post( $sender, 'send_to_client', $client_id, '430 no such article found' );
           return;
        }
        foreach my $msg_id ( keys %{ $groups{$group} } ) {
          $kernel->post( $sender, 'send_to_client', $client_id, "220 1 $msg_id article retrieved - head and body follow" );
          $kernel->post( $sender, 'send_to_client', $client_id, $_ ) for @{ $groups{$group}->{$msg_id } };
          $kernel->post( $sender, 'send_to_client', $client_id, '.' );
        }
        return;
      }

      __END__
      Newsgroups: perl.cpan.testers
      Path: nntp.perl.org
      Date: Fri,  1 Dec 2006 09:27:56 +0000
      Subject: PASS POE-Component-IRC-5.14 cygwin-thread-multi-64int 1.5.21(0.15642)
      From: chris@bingosnet.co.uk
      Message-ID: <perl.cpan.testers-381062@nntp.perl.org>

      This distribution has been tested as part of the cpan-testers
      effort to test as many new uploads to CPAN as possible.  See
      http://testers.cpan.org/

DESCRIPTION

    POE::Component::Server::NNTP is a POE component that implements an RFC
    977 http://www.faqs.org/rfcs/rfc977.html NNTP server. It is the
    companion component to POE::Component::Client::NNTP which implements
    NNTP client functionality.

    You spawn an NNTP server component, create your POE sessions then
    register your session to receive events. Whenever clients connect,
    disconnect or send valid NNTP protocol commands you will receive an
    event and an unique client ID. You then parse and process the commands
    given and send back applicable NNTP responses.

    This component doesn't implement the news database and as such is not
    by itself a complete NNTP daemon implementation.

CONSTRUCTOR

    spawn

      Takes a number of optional arguments:

        'alias', set an alias on the component;
        'address', bind the component to a particular address, defaults to INADDR_ANY;
        'port', start the listening server on a different port, defaults to 119;
        'options', a hashref of POE::Session options;
        'posting', a true or false value that determines whether the poco
                   responds with a 200 or 201 to clients;
        'handle_connects', true or false whether the poco sends 200/201
                   responses to connecting clients automagically;
        'extra_cmds', an arrayref of additional NNTP commands that you
                   wish to implement.

      Returns a POE::Component::Server::NNTP object.

METHODS

    session_id

      Returns the POE::Session ID of the component.

    shutdown

      Terminates the component. Shuts down the listener and disconnects
      connected clients.

    send_event

      Sends an event through the component's event handling system.

    send_to_client

      Send some output to a connected client. First parameter must be a
      valid client id. Second parameter is a string of text to send.

INPUT

    These are events that the component will accept:

    register

      Takes N arguments: a list of event names that your session wants to
      listen for, minus the 'nntpd_' prefix, ( this is similar to
      POE::Component::IRC ).

      Registering for 'all' will cause it to send all NNTPD-related events
      to you; this is the easiest way to handle it.

    unregister

      Takes N arguments: a list of event names which you don't want to
      receive. If you've previously done a 'register' for a particular
      event which you no longer care about, this event will tell the NNTPD
      to stop sending them to you. (If you haven't, it just ignores you. No
      big deal).

    shutdown

      Terminates the component. Shuts down the listener and disconnects
      connected clients.

    send_event

      Sends an event through the component's event handling system.

    send_to_client

      Send some output to a connected client. First parameter must be a
      valid client ID. Second parameter is a string of text to send.

OUTPUT

    The component sends the following events to registered sessions:

    nntpd_registered

      This event is sent to a registering session. ARG0 is
      POE::Component::Server::NNTP object.

    nntpd_listener_failed

      Generated if the component cannot either start a listener or there is
      a problem accepting client connections. ARG0 contains the name of the
      operation that failed. ARG1 and ARG2 hold numeric and string values
      for $!, respectively.

    nntpd_connection

      Generated whenever a client connects to the component. ARG0 is the
      client ID, ARG1 is the client's IP address, ARG2 is the client's TCP
      port. ARG3 is our IP address and ARG4 is our socket port.

    nntpd_disconnected

      Generated whenever a client disconnects. ARG0 is the client ID.

    nntpd_cmd_*

      Generated for each NNTP command that a connected client sends to us.
      ARG0 is the client ID. ARG1 .. ARGn are any parameters that are sent
      with the command. Check the RFC http://www.faqs.org/rfcs/rfc977.html
      for details.

    nntpd_posting

      When the component receives a posting from a client, either as the
      result of a IHAVE or POST command, this event is issued. ARG0 will be
      the client ID. ARG1 will be either a '335' or '340' indicating what
      the posting relates to ( either an IHAVE or POST ). ARG2 will be an
      arrayref containing the raw lines that the client sent us. No
      additional parsing is undertaken on this data.

PLUGINS

    POE::Component::Server::NNTP utilises POE::Component::Pluggable to
    enable a POE::Component::IRC type plugin system.

 PLUGIN HANDLER TYPES

    There are two types of handlers that can registered for by plugins,
    these are

    NNTPD

      These are the 'nntpd_' prefixed events that are generated. In a
      handler arguments are passed as scalar refs so that you may mangle
      the values if required.

    NNTPC

      These are generated whenever a response is sent to a client. Again,
      any arguments passed are scalar refs for manglement. There is really
      on one type of this handler generated 'NNTPC_response'

 PLUGIN EXIT CODES

    Plugin handlers should return a particular value depending on what
    action they wish to happen to the event. These values are available as
    constants which you can use with the following line:

      use POE::Component::Server::NNTP::Constants qw(:ALL);

    The return values have the following significance:

    NNTPD_EAT_NONE

      This means the event will continue to be processed by remaining
      plugins and finally, sent to interested sessions that registered for
      it.

    NNTP_EAT_CLIENT

      This means the event will continue to be processed by remaining
      plugins but it will not be sent to any sessions that registered for
      it. This means nothing will be sent out on the wire if it was an
      NNTPC event, beware!

    NNTPD_EAT_PLUGIN

      This means the event will not be processed by remaining plugins, it
      will go straight to interested sessions.

    NNTPD_EAT_ALL

      This means the event will be completely discarded, no plugin or
      session will see it. This means nothing will be sent out on the wire
      if it was an NNTPC event, beware!

 PLUGIN METHODS

    The following methods are available:

    pipeline

      Returns the POE::Component::Pluggable::Pipeline object.

    plugin_add

      Accepts two arguments:

        The alias for the plugin
        The actual plugin object

      The alias is there for the user to refer to it, as it is possible to
      have multiple plugins of the same kind active in one
      POE::Component::Server::NNTP object.

      This method goes through the pipeline's push() method.

       This method will call $plugin->plugin_register( $nntpd )

      Returns the number of plugins now in the pipeline if plugin was
      initialized, undef if not.

    plugin_del

      Accepts one argument:

        The alias for the plugin or the plugin object itself

      This method goes through the pipeline's remove() method.

      This method will call $plugin->plugin_unregister( $nntpd )

      Returns the plugin object if the plugin was removed, undef if not.

    plugin_get

      Accepts one argument:

        The alias for the plugin

      This method goes through the pipeline's get() method.

      Returns the plugin object if it was found, undef if not.

    plugin_list

      Has no arguments.

      Returns a hashref of plugin objects, keyed on alias, or an empty list
      if there are no plugins loaded.

    plugin_order

      Has no arguments.

      Returns an arrayref of plugin objects, in the order which they are
      encountered in the pipeline.

    plugin_register

      Accepts the following arguments:

        The plugin object
        The type of the hook, NNTPD or NNTPC
        The event name(s) to watch

      The event names can be as many as possible, or an arrayref. They
      correspond to the prefixed events and naturally, arbitrary events
      too.

      You do not need to supply events with the prefix in front of them,
      just the names.

      It is possible to register for all events by specifying 'all' as an
      event.

      Returns 1 if everything checked out fine, undef if something's
      seriously wrong

    plugin_unregister

      Accepts the following arguments:

        The plugin object
        The type of the hook, NNTPD or NNTPC
        The event name(s) to unwatch

      The event names can be as many as possible, or an arrayref. They
      correspond to the prefixed events and naturally, arbitrary events
      too.

      You do not need to supply events with the prefix in front of them,
      just the names.

      It is possible to register for all events by specifying 'all' as an
      event.

      Returns 1 if all the event name(s) was unregistered, undef if some
      was not found.

 PLUGIN TEMPLATE

    The basic anatomy of a plugin is:

            package Plugin;

            # Import the constants, of course you could provide your own
            # constants as long as they map correctly.
            use POE::Component::Server::NNTP::Constants qw( :ALL );

            # Our constructor
            sub new {
                    ...
            }

            # Required entry point for plugins
            sub plugin_register {
                    my( $self, $nntpd ) = @_;

                    # Register events we are interested in
                    $nntpd->plugin_register( $self, 'NNTPD', qw(all) );

                    # Return success
                    return 1;
            }

            # Required exit point for pluggable
            sub plugin_unregister {
                    my( $self, $nntpd ) = @_;

                    # Pluggable will automatically unregister events for the plugin

                    # Do some cleanup...

                    # Return success
                    return 1;
            }

            sub _default {
                    my( $self, $nntpd, $event ) = splice @_, 0, 3;

                    print "Default called for $event\n";

                    # Return an exit code
                    return NNTPD_EAT_NONE;
            }

SEE ALSO

    POE::Component::Client::NNTP

    RFC 977 http://www.faqs.org/rfcs/rfc977.html

    RFC 1036 http://www.faqs.org/rfcs/rfc1036.html

    POE::Component::Pluggable

AUTHOR

    Chris Williams <chris@bingosnet.co.uk>

COPYRIGHT AND LICENSE

    This software is copyright (c) 2016 by Chris Williams.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.