Net::NNTP(3pm) Perl Programmers Reference Guide Net::NNTP(3pm)
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
$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.
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>.
SEE ALSO
Net::Cmd(3), IO::Socket::SSL(3)
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 3.13
DATE
23 Dec 2020
HISTORY
See the Changes file.
perl v5.34.0 2021-01-20 Net::NNTP(3pm)
perl 5.34.0 - Generated Thu Mar 3 15:25:14 CST 2022