Ubuntu Manpage: Net::NNTP - NNTP Client class

NAME

       Net::NNTP - NNTP Client class

SYNOPSIS

           use Net::NNTP;

           $nntp = Net::NNTP->new("some.host.name");
           $nntp->quit;

           # start with SSL, e.g. nntps
           $nntp = Net::NNTP->new("some.host.name", SSL => 1);

           # start with plain and upgrade to SSL
           $nntp = Net::NNTP->new("some.host.name");
           $nntp->starttls;

DESCRIPTION

"Net::NNTP" is a class implementing a simple NNTP client in Perl as described in RFC977
and RFC4642. With IO::Socket::SSL installed it also provides support for implicit and
explicit TLS encryption, i.e. NNTPS or NNTP+STARTTLS.

The Net::NNTP class is a subclass of Net::Cmd and (depending on avaibility) of
IO::Socket::IP, IO::Socket::INET6 or IO::Socket::INET.

Class Methods
"new([$host][, %options])"
This is the constructor for a new Net::NNTP object. $host is the name of the remote
host to which a NNTP connection is required. If not given then it may be passed as the
"Host" option described below. If no host is passed then two environment variables are
checked, first "NNTPSERVER" then "NEWSHOST", then "Net::Config" is checked, and if a
host is not found then "news" is used.

%options are passed in a hash like fashion, using key and value pairs. Possible
options are:

Host - NNTP host to connect to. It may be a single scalar, as defined for the
"PeerAddr" option in IO::Socket::INET, or a reference to an array with hosts to try in
turn. The "host" method will return the value which was used to connect to the host.

Port - port to connect to. Default - 119 for plain NNTP and 563 for immediate SSL
(nntps).

SSL - If the connection should be done from start with SSL, contrary to later upgrade
with "starttls". You can use SSL arguments as documented in IO::Socket::SSL, but it
will usually use the right arguments already.

Timeout - Maximum time, in seconds, to wait for a response from the NNTP server, a
value of zero will cause all IO operations to block. (default: 120)

Debug - Enable the printing of debugging information to STDERR

Reader - If the remote server is INN then initially the connection will be to innd, by
default "Net::NNTP" will issue a "MODE READER" command so that the remote server
becomes nnrpd. If the "Reader" option is given with a value of zero, then this command
will not be sent and the connection will be left talking to innd.

LocalAddr and LocalPort - These parameters are passed directly to IO::Socket to allow
binding the socket to a specific local address and port.

Domain - This parameter is passed directly to IO::Socket and makes it possible to
enforce IPv4 connections even if IO::Socket::IP is used as super class. Alternatively
Family can be used.

Object Methods
Unless otherwise stated all methods return either a true or false value, with true meaning
that the operation was a success. When a method states that it returns a value, failure
will be returned as undef or an empty list.

"Net::NNTP" inherits from "Net::Cmd" so methods defined in "Net::Cmd" may be used to send
commands to the remote NNTP server in addition to the methods documented here.

"host()"
Returns the value used by the constructor, and passed to IO::Socket::INET, to connect
to the host.

"starttls()"
Upgrade existing plain connection to SSL. Any arguments necessary for SSL must be
given in "new" already.

"article([{$msgid|$msgnum}[, $fh]])"
Retrieve the header, a blank line, then the body (text) of the specified article.

If $fh is specified then it is expected to be a valid filehandle and the result will
be printed to it, on success a true value will be returned. If $fh is not specified
then the return value, on success, will be a reference to an array containing the
article requested, each entry in the array will contain one line of the article.

If no arguments are passed then the current article in the currently selected
newsgroup is fetched.

$msgnum is a numeric id of an article in the current newsgroup, and will change the
current article pointer. $msgid is the message id of an article as shown in that
article's header. It is anticipated that the client will obtain the $msgid from a
list provided by the "newnews" command, from references contained within another
article, or from the message-id provided in the response to some other commands.

If there is an error then "undef" will be returned.

"body([{$msgid|$msgnum}[, [$fh]])"
Like "article" but only fetches the body of the article.

"head([{$msgid|$msgnum}[, [$fh]])"
Like "article" but only fetches the headers for the article.

"articlefh([{$msgid|$msgnum}])"
"bodyfh([{$msgid|$msgnum}])"
"headfh([{$msgid|$msgnum}])"
These are similar to article(), body() and head(), but rather than returning the
requested data directly, they return a tied filehandle from which to read the article.

"nntpstat([{$msgid|$msgnum}])"
The "nntpstat" command is similar to the "article" command except that no text is
returned. When selecting by message number within a group, the "nntpstat" command
serves to set the "current article pointer" without sending text.

Using the "nntpstat" command to select by message-id is valid but of questionable
value, since a selection by message-id does not alter the "current article pointer".

Returns the message-id of the "current article".

"group([$group])"
Set and/or get the current group. If $group is not given then information is returned
on the current group.

In a scalar context it returns the group name.

In an array context the return value is a list containing, the number of articles in
the group, the number of the first article, the number of the last article and the
group name.

"help()"
Request help text (a short summary of commands that are understood by this
implementation) from the server. Returns the text or undef upon failure.

"ihave($msgid[, $message])"
The "ihave" command informs the server that the client has an article whose id is
$msgid. If the server desires a copy of that article and $message has been given then
it will be sent.

Returns true if the server desires the article and $message was successfully sent, if
specified.

If $message is not specified then the message must be sent using the "datasend" and
"dataend" methods from Net::Cmd

$message can be either an array of lines or a reference to an array and must be
encoded by the caller to octets of whatever encoding is required, e.g. by using the
Encode module's "encode()" function.

"last()"
Set the "current article pointer" to the previous article in the current newsgroup.

Returns the message-id of the article.

"date()"
Returns the date on the remote server. This date will be in a UNIX time format
(seconds since 1970)

"postok()"
"postok" will return true if the servers initial response indicated that it will allow
posting.

"authinfo($user, $pass)"
Authenticates to the server (using the original AUTHINFO USER / AUTHINFO PASS form,
defined in RFC2980) using the supplied username and password. Please note that the
password is sent in clear text to the server. This command should not be used with
valuable passwords unless the connection to the server is somehow protected.

"authinfo_simple($user, $pass)"
Authenticates to the server (using the proposed NNTP V2 AUTHINFO SIMPLE form, defined
and deprecated in RFC2980) using the supplied username and password. As with
"authinfo" the password is sent in clear text.

"list()"
Obtain information about all the active newsgroups. The results is a reference to a
hash where the key is a group name and each value is a reference to an array. The
elements in this array are:- the last article number in the group, the first article
number in the group and any information flags about the group.

"newgroups($since[, $distributions])"
$since is a time value and $distributions is either a distribution pattern or a
reference to a list of distribution patterns. The result is the same as "list", but
the groups return will be limited to those created after $since and, if specified, in
one of the distribution areas in $distributions.

"newnews($since[, $groups[, $distributions]])"
$since is a time value. $groups is either a group pattern or a reference to a list of
group patterns. $distributions is either a distribution pattern or a reference to a
list of distribution patterns.

Returns a reference to a list which contains the message-ids of all news posted after
$since, that are in a groups which matched $groups and a distribution which matches
$distributions.

"next()"
Set the "current article pointer" to the next article in the current newsgroup.

Returns the message-id of the article.

"post([$message])"
Post a new article to the news server. If $message is specified and posting is allowed
then the message will be sent.

If $message is not specified then the message must be sent using the "datasend" and
"dataend" methods from Net::Cmd

The message, either sent via "datasend" or as the $message parameter, must be in the
format as described by RFC822 and must contain From:, Newsgroups: and Subject:
headers.

"postfh()"
Post a new article to the news server using a tied filehandle. If posting is allowed,
this method will return a tied filehandle that you can print() the contents of the
article to be posted. You must explicitly close() the filehandle when you are
finished posting the article, and the return value from the close() call will indicate
whether the message was successfully posted.

"slave()"
Tell the remote server that I am not a user client, but probably another news server.

"quit()"
Quit the remote server and close the socket connection.

"can_inet6()"
Returns whether we can use IPv6.

"can_ssl()"
Returns whether we can use SSL.

Extension Methods
These methods use commands that are not part of the RFC977 documentation. Some servers may
not support all of them.

"newsgroups([$pattern])"
Returns a reference to a hash where the keys are all the group names which match
$pattern, or all of the groups if no pattern is specified, and each value contains the
description text for the group.

"distributions()"
Returns a reference to a hash where the keys are all the possible distribution names
and the values are the distribution descriptions.

"distribution_patterns()"
Returns a reference to an array where each element, itself an array reference,
consists of the three fields of a line of the distrib.pats list maintained by some
NNTP servers, namely: a weight, a wildmat and a value which the client may use to
construct a Distribution header.

"subscriptions()"
Returns a reference to a list which contains a list of groups which are recommended
for a new user to subscribe to.

"overview_fmt()"
Returns a reference to an array which contain the names of the fields returned by
"xover".

"active_times()"
Returns a reference to a hash where the keys are the group names and each value is a
reference to an array containing the time the groups was created and an identifier,
possibly an Email address, of the creator.

"active([$pattern])"
Similar to "list" but only active groups that match the pattern are returned.
$pattern can be a group pattern.

"xgtitle($pattern)"
Returns a reference to a hash where the keys are all the group names which match
$pattern and each value is the description text for the group.

"xhdr($header, $message_spec)"
Obtain the header field $header for all the messages specified.

The return value will be a reference to a hash where the keys are the message numbers
and each value contains the text of the requested header for that message.

"xover($message_spec)"
The return value will be a reference to a hash where the keys are the message numbers
and each value contains a reference to an array which contains the overview fields for
that message.

The names of the fields can be obtained by calling "overview_fmt".

"xpath($message_id)"
Returns the path name to the file on the server which contains the specified message.

"xpat($header, $pattern, $message_spec)"
The result is the same as "xhdr" except the is will be restricted to headers where the
text of the header matches $pattern

"xrover($message_spec)"
The XROVER command returns reference information for the article(s) specified.

Returns a reference to a HASH where the keys are the message numbers and the values
are the References: lines from the articles

"listgroup([$group])"
Returns a reference to a list of all the active messages in $group, or the current
group if $group is not specified.

"reader()"
Tell the server that you are a reader and not another server.

This is required by some servers. For example if you are connecting to an INN server
and you have transfer permission your connection will be connected to the transfer
daemon, not the NNTP daemon. Issuing this command will cause the transfer daemon to
hand over control to the NNTP daemon.

Some servers do not understand this command, but issuing it and ignoring the response
is harmless.

Unsupported
The following NNTP command are unsupported by the package, and there are no plans to do
so.

AUTHINFO GENERIC
XTHREAD
XSEARCH
XINDEX

Definitions
$message_spec
$message_spec is either a single message-id, a single message number, or a reference
to a list of two message numbers.

If $message_spec is a reference to a list of two message numbers and the second number
in a range is less than or equal to the first then the range represents all messages
in the group after the first message number.

NOTE For compatibility reasons only with earlier versions of Net::NNTP a message spec
can be passed as a list of two numbers, this is deprecated and a reference to the list
should now be passed

$pattern
The "NNTP" protocol uses the "WILDMAT" format for patterns. The WILDMAT format was
first developed by Rich Salz based on the format used in the UNIX "find" command to
articulate file names. It was developed to provide a uniform mechanism for matching
patterns in the same manner that the UNIX shell matches filenames.

Patterns are implicitly anchored at the beginning and end of each string when testing
for a match.

There are five pattern matching operations other than a strict one-to-one match
between the pattern and the source to be checked for a match.

The first is an asterisk "*" to match any sequence of zero or more characters.

The second is a question mark "?" to match any single character. The third specifies a
specific set of characters.

The set is specified as a list of characters, or as a range of characters where the
beginning and end of the range are separated by a minus (or dash) character, or as any
combination of lists and ranges. The dash can also be included in the set as a
character it if is the beginning or end of the set. This set is enclosed in square
brackets. The close square bracket "]" may be used in a set if it is the first
character in the set.

The fourth operation is the same as the logical not of the third operation and is
specified the same way as the third with the addition of a caret character "^" at the
beginning of the test string just inside the open square bracket.

The final operation uses the backslash character to invalidate the special meaning of
an open square bracket "[", the asterisk, backslash or the question mark. Two
backslashes in sequence will result in the evaluation of the backslash as a character
with no special meaning.

Examples
"[^]-]"
matches any single character other than a close square bracket or a minus
sign/dash.

*bdc
matches any string that ends with the string "bdc" including the string "bdc"
(without quotes).

"[0-9a-zA-Z]"
matches any single printable alphanumeric ASCII character.

"a??d"
matches any four character string which begins with a and ends with d.

EXPORTS

       None.

KNOWN BUGS

       See <https://rt.cpan.org/Dist/Display.html?Status=Active&Queue=libnet>.

AUTHOR

       Graham Barr <gbarr@pobox.com <mailto:gbarr@pobox.com>>.

       Steve Hay <shay@cpan.org <mailto:shay@cpan.org>> is now maintaining libnet as of version
       1.22_02.

COPYRIGHT

       Copyright (C) 1995-1997 Graham Barr.  All rights reserved.

       Copyright (C) 2013-2016, 2020 Steve Hay.  All rights reserved.

LICENCE

       This module is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself, i.e. under the terms of either the GNU General Public License or the
       Artistic License, as specified in the LICENCE file.

VERSION

       Version 3.14

DATE

       23 Dec 2020

HISTORY

       See the Changes file.