:trivial-nntp (:tnntp)

Common lisp tools for connecting to and crawling around NNTP servers. It uses usocket and cl+ssl, and therefore handles simple or SSL-encrypted NNTP connections.

This is a minimalistic effort; however watch this:

     CL-USER> (in-package :tnntp)
     TNNTP> (command "HELP")
     "100 Legal commands^M"
     1
     TNNTP> (rlist)
     "  ARTICLE [message-ID|number]^M"
     "  AUTHINFO USER name|PASS password|GENERIC program [argument ...]^M"
     "  BODY [message-ID|number]^M" "  CAPABILITIES [keyword]^M"
     "  COMPRESS DEFLATE^M" "  DATE^M" "  GROUP newsgroup^M"
     "..."
     "Report problems to <usenet@fleegle.mixmin.net>.^M"
     TNNTP> (disconnect)
     "205 Bye!^M"
     2
     CL-USER>

This simple test connect to news.mixmin.net (see tnntp.lisp). To connect to your server, create a server just like this (with your own info, of course):

(defparameter *server* ;; or keep this in some other place...
  (make-server :name "news.mixmin.net"
	       :port 119
	       :user nil
	       :password nil
	       :ssl nil
	       )
(defparameter *conn* ;; or create an array of connections or whatever
  (make-conn :server *server* :group "alt.whatever")

At the core, the server structure (see 'tnntp.lisp') contains information about the URL, port, authentication. A connection keeps track of the socket/stream state. The system will transparently reconnect and restore current group on a connection should the server close the connection.

Commands are sent with something like (command connection "commandstring" :expecting 2 ) The expecting parameter, if specified, makes sure that the response in in 200-299 range (only first digit is checked). For commands with an additional parameter such as "GROUP groupname" the :also parameter avoids building command strings: (send-command "GROUP" :also groupname)

Responses are read with

• (rline) - read one line
• (rlist) - read lines terminated by ".^M" into a list; optionally process with :proc.

Lines are returned unprocessed, with control-M character. Rationale: you will probably parse the lines anyway, so there is little reason to worry about that.

WORKFLOW

1. Create a server structure with your server url, port and authentication info.
2. Create a connection structure with the server.
3. (command ...) "MODE READER" is a good start. If you send commands that return data, make sure to read everything up to and including the termination line containing a single dot. See (rlist) for details. If you don't you will get out of sync and send-command will not get a good response line.
4. (disconnect) when done -- it sends "QUIT" and kills the sockets
5. Write a news transport, a reader, a downloader, or anything that you are discouraged to do in this article

A SIMPLE EXAMPLE

(load-groups)
(search-groups "book")

Search the grouplist for anything containing the word 'book'; regex expressions allowed!

References: *

• USOCKET API
• RFC 977: Network News Transfer Protocol (1986)
• RFC 1036: Standard for Interchange of USENET Messages (1987)
• Don't Write a Newsreader (1995)