## $Id: nntp.pm,v 1.1 1997/11/18 00:33:21 neeri Exp $# Implementation of the Network News Transfer Protocol (RFC 977)#package LWP::Protocol::nntp;require LWP::Protocol;@ISA = qw(LWP::Protocol);require LWP::Socket;require LWP::Debug;require HTTP::Request;require HTTP::Response;use HTTP::Status ();use strict;use vars qw($NNTP_SERVER $NNTP_PORT);$NNTP_SERVER = $ENV{NNTP_SERVER} || "news";$NNTP_PORT   = 119;sub request{    my($self, $request, $proxy, $arg, $size, $timeout) = @_;    LWP::Debug::trace('()');    $size = 4096 unless $size;    # Check for proxy    if (defined $proxy) {	return HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,				   'You can not proxy through NNTP');    }    # Check that the scheme is as expected    my $url = $request->url;    my $scheme = $url->scheme;    unless ($scheme eq 'news') {	return HTTP::Response->new(&HTTP::Status::RC_INTERNAL_SERVER_ERROR,				   "LWP::Protocol::nntp::request called for '$scheme'");    }    # check for a valid method    my $method = $request->method;    unless ($method eq 'GET' || $method eq 'HEAD' || $method eq 'POST') {	return HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,				   'Library does not allow method ' .				   "$method for 'news:' URLs");    }    # extract the identifier and check against posting to an article    my $groupart = $url->groupart;    my $is_art = $groupart =~ /@/;    if ($is_art && $method eq 'POST') {	return HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,				   "Can't post to an article <$groupart>");    }    # Create a socket and connect to the NNTP server.  We use our own    # specialization of the LWP::Socket class.  This new class is defined    # below.    my $nntp = new LWP::Protocol::nntp::Socket;  # What an ugly name    $nntp->connect($NNTP_SERVER, $NNTP_PORT);    # Check the initial welcome message from the NNTP server    if ($nntp->response($timeout) != 2) {	return HTTP::Response->new(&HTTP::Status::RC_SERVICE_UNAVAILABLE,				   $nntp->message);    }    my $response = HTTP::Response->new(&HTTP::Status::RC_OK, "OK");    my $mess = $nntp->message;    LWP::Debug::debug($mess);    # Try to extract server name from greating message.    # Don't know if this works well for a large class of servers, but    # this works for our server.    $mess =~ s/\s+ready\b.*//;    $mess =~ s/^\S+\s+//;    $response->header('Server', $mess);    # First we handle posting of articles    if ($method eq 'POST') {	$request->header("Newsgroups", $groupart)	    unless $request->header("Newsgroups");	if ($nntp->cmd("POST") != 3) {	    return HTTP::Response->new(&HTTP::Status::RC_FORBIDDEN,				       $nntp->message);	}	$nntp->write($request->headers_as_string("\015\012") . "\015\012");	my $content = $request->content;	$content =~ s/^\./../gm;  # must escape "." at the beginning of lies	$nntp->write($content);	$nntp->write("\015\012.\015\012"); 	# Terminate message	if ($nntp->response != 2) {	    return HTTP::Response->new(&HTTP::Status::RC_BAD_REQUEST,				       $nntp->message);	}	$response->code(&HTTP::Status::RC_ACCEPTED);	$response->message($nntp->message);	return $response;    }    # The method must be "GET" or "HEAD" by now    if (!$is_art) {	if ($nntp->cmd("GROUP $groupart") != 2) {	    return HTTP::Response->new(&HTTP::Status::RC_NOT_FOUND,				       $nntp->message);	}	return HTTP::Response->new(&HTTP::Status::RC_NOT_IMPLEMENTED,				   "GET newsgroup not implemented yet");    }    # Send command to server to retrieve an article (or just the headers)    my $cmd = ($method eq 'HEAD' ? 'HEAD' : 'ARTICLE') . " <$groupart>";    if ($nntp->cmd($cmd, $timeout) != 2) {	return HTTP::Response->new(&HTTP::Status::RC_NOT_FOUND,				   $nntp->message);    }    LWP::Debug::debug($nntp->message);    # Must read article data until ".".  Here we just "fake" it using the    # read_until method.  We should really use the normal read() method    # so that we are able to handle real big articles much better.    $nntp->read_until('\015?\012\.\015?\012', \$mess, $size, $timeout);    my($headers, $body) = split(/(?:\015?\012){2}/, $mess, 2);    # Parse headers    my($key, $val);    for (split(/\015?\012/, $headers)) {	if (/^(\S+):\s*(.*)/) {	    $response->push_header($key, $val) if $key;	    ($key, $val) = ($1, $2);	} elsif (/^\s+(.*)/) {	    next unless $key;	    $val .= $1;	}    }    $response->push_header($key, $val) if $key;    # Ensure that there is a Content-Type header    $response->header("Content-Type", "text/plain")	unless $response->header("Content-Type");    # Collect the body    if (defined $body) {	$body =~ s/\r//g;	$body =~ s/^\.\././gm;	$response = $self->collect_once($arg, $response, $body);    }    # Say godbye to the server    $nntp->cmd("QUIT");    $nntp = undef;    $response;}# Out special NNTP socket class.  This is just like LWP::Sockets, but# implement a few new methods.##    $sock->cmd("CMD", $timeout);  # Sends command to server and return the#                                  # first digit of the response code##    $sock->response($timeout);    # Read response line from server and#                                  # return first digit of the response code.##    $sock->code                   # Return the full response code (last one)#    $sock->message                # Return response message.#package LWP::Protocol::nntp::Socket;use vars qw(@ISA);@ISA = qw(LWP::Socket);sub cmd {    my($self, $cmd, $timeout) = @_;    $self->write("$cmd\015\012", $timeout);    $self->response($timeout);}sub response {    my($self, $timeout) = shift;    my $resp;    $self->read_until("\015?\012", \$resp, undef, $timeout);    $resp =~ s/^(\d{3})\s*//;    my $code = $1;    $self->{nntp_message} = $resp;    $self->{nntp_code} = $code;    substr($code, 0, 1);}sub message { shift->{'nntp_message'}; }sub code    { shift->{'nntp_code'};    }package LWP::Protocol::nntp;1;