nntp - Tcl client for the NNTP protocol
The package nntp provides a simple Tcl-only client library for the NNTP protocol. It works by opening the standard NNTP socket on the server, and then providing a Tcl API to access the NNTP protocol commands. All server errors are returned as Tcl errors (thrown) which must be caught with the Tcl catch command.
The command opens a socket connection to the specified NNTP server and creates a new nntp object with an associated global Tcl command whose name is nntpName. This command may be used to access the various NNTP protocol commands for the new connection. The default port number is "119" and the default host is "news". These defaults can be overridden with the environment variables NNTPPORT and NNTPHOST respectively.
Some of the commands supported by this package are not part of the nntp rfc 977 (http://www.rfc-editor.org/rfc/rfc977.txt) and will not be available (or implemented) on all nntp servers.
The access command nntpName has the following general form:
Option and the args determine the exact behavior of the command.
Query the server for article msgid from the current group. The article is returned as a valid tcl list which contains the headers, followed by a blank line, and then followed by the body of the article. Each element in the list is one line of the article.
Send authentication information (username and password) to the server.
Query the server for the body of the article msgid from the current group. The body of the article is returned as a valid tcl list. Each element in the list is one line of the body of the article.
Query and configure options of the nntp connection object. Currently only one option is supported, -binary. When set articles are retrieved as binary data instead of text. The only methods affected by this are article and body.
One application of this option would be the download of articles containing yEnc encoded images. Although encoded the data is still mostly binary and retrieving it as text will corrupt the information.
See package yencode for both encoder and decoder of such data.
Query the server for the servers current date. The date is returned in the format YYYYMMDDHHMMSS.
Optionally set the current group, and retrieve information about the currently selected group. Returns the estimated number of articles in the group followed by the number of the first article in the group, followed by the last article in the group, followed by the name of the group.
Query the server for the headers of the article msgid from the current group. The headers of the article are returned as a valid tcl list. Each element in the list is one line of the headers of the article.
Retrieves a list of the commands that are supported by the news server that is currently attached to.
Sets the current article pointer to point to the previous message (if there is one) and returns the msgid of that message.
Returns a tcl list of valid newsgroups and associated information. Each newsgroup is returned as an element in the tcl list with the following format:
group last first p
where <group> is the name of the newsgroup, <last> is the number of the last known article currently in that newsgroup, <first> is the number of the first article currently in the newsgroup, and <p> is either 'y' or 'n' indicating whether posting to this newsgroup is allowed ('y') or prohibited ('n').
The <first> and <last> fields will always be numeric. They may have leading zeros. If the <last> field evaluates to less than the <first> field, there are no articles currently on file in the newsgroup.
Query the server for a list of all the messages (message numbers) in the group specified by the argument group or by the current group if the group argument was not passed.
Query the server for its nntp 'MODE READER' response string.
Query the server for a list of all the new newsgroups created since the time specified by the argument since. The argument since can be any time string that is understood by clock scan. The tcl list of newsgroups is returned in a similar form to the list of groups returned by the nntpName list command. Each element of the list has the form:
group last first p
where <group> is the name of the newsgroup, <last> is the number of the last known article currently in that newsgroup, <first> is the number of the first article currently in the newsgroup, and <p> is either 'y' or 'n' indicating whether posting to this newsgroup is allowed ('y') or prohibited ('n').
Query the server for a list of new articles posted to the current group in the last day.
Query the server for a list of new articles posted to the current group since the time specified by the argument since. The argument since can be any time string that is understood by clock scan.
Query the server for a list of new articles posted to the group specified by the argument group since the time specified by the argument since (or in the past day if no since argument is passed. The argument since can be any time string that is understood by clock scan.
Sets the current article pointer to point to the next message (if there is one) and returns the msgid of that message.
Posts an article of the form specified in RFC 1036 (http://www.rfc-editor.org/rfc/rfc1036.txt, successor to RFC 850) to the current news group.
Identifies a connection as being made from a slave nntp server. This might be used to indicate that the connection is serving multiple people and should be given priority. Actual use is entirely implementation dependent and may vary from server to server.
The stat command is similar to the article command except that no text is returned. When selecting by message number within a group, the stat command serves to set the current article pointer without sending text. The returned acknowledgment response will contain the message-id, which may be of some value. Using the stat 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"
Gracefully close the connection after sending a NNTP QUIT command down the socket.
Returns a tcl list where each element is of the form:
newsgroup description
If a group_pattern is specified then only newsgroups that match the pattern will have their name and description returned.
Returns the specified header field value for the current message or for a list of messages from the current group. field is the title of a field in the header such as from, subject, date, etc. If range is not specified or is "" then the current message is queried. The command returns a list of elements where each element has the form of:
msgid value
Where msgid is the number of the message and value is the value set for the queried field. The range argument can be in any of the following forms:
The current message is queried.
All messages between msgid1 and msgid2 (including msgid1 and msgid2) are queried.
All messages between msgid1 and msgid2 (including msgid1 and msgid2) are queried.
Returns header information for the current message or for a range of messages from the current group. The information is returned in a tcl list where each element is of the form:
msgid subject from date idstring bodysize headersize xref
If range is not specified or is "" then the current message is queried. The range argument can be in any of the following forms:
The current message is queried.
All messages between msgid1 and msgid2 (including msgid1 and msgid2) are queried.
All messages between msgid1 and msgid2 (including msgid1 and msgid2) are queried.
Returns the specified header field value for a specified message or for a list of messages from the current group where the messages match the pattern(s) given in the pattern_list. field is the title of a field in the header such as from, subject, date, etc. The information is returned in a tcl list where each element is of the form:
msgid value
Where msgid is the number of the message and value is the value set for the queried field. The range argument can be in any of the following forms:
The message specified by msgid is queried.
All messages between msgid1 and msgid2 (including msgid1 and msgid2) are queried.
All messages between msgid1 and msgid2 (including msgid1 and msgid2) are queried.
A bigger example for posting a single article.
package require nntp
set n [nntp::nntp NNTP_SERVER]
$n post "From: USER@DOMAIN.EXT (USER_FULL)
Path: COMPUTERNAME!USERNAME
Newsgroups: alt.test
Subject: Tcl test post -ignore
Message-ID: <[pid][clock seconds]
@COMPUTERNAME>
Date: [clock format [clock seconds] -format "%a, %d %
b %y %H:%M:%S GMT" -gmt true]
Test message body"
This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category nntp of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.
Networking