Hardcopy with TCP/IP? Sure thing.

["Robert W. Kerns" <RWK@scrc-yukon.arpa>]

    Date: Sun, 13 Dec 87 22:13 EST
    From: Robert W. Kerns <RWK@YUKON.SCRC.Symbolics.COM>

    Your code seems to have been slightly mangled somehow;
    your UNWIND-PROTECT has no cleanup-forms.

    Date: Mon, 14 Dec 87 19:37:08 +0100
    From: mcvax!jungfrau!ceb@uunet.UU.NET

    So it made it through after all.  Oh well.

    Right you are about the cleanup form.  It is

    (when stream (send stream :close :abort))

    Feel free to pass it  on, or better yet, gadgets like this should be
    part of the release (there wasn't much to it), 

						   but it took me a few
    hours of swimming through the lisp code to figure out what to do.
    Others are writing lgpd servers (!).

    Anyway, thanks for pointing out the error.


	Date: Sat, 12 Dec 87 20:40:31 +0100
	From: mcvax!jungfrau!ceb@uunet.UU.NET

	Assuming that your unix machine's tcp software has an rexec deamon
	(usually called /etc/rexecd), then the following will do the job.  You
	load this file into your Lisp machine and be sure it is saved into the
	world.  

	Another thing you will have to do is add a service to the unix
	machines host entry in the namespace.  This service is

	HARDCOPY <tcp-medium> UNIX-REXEC

	where <tcp-medium> is whatever the medium string for TCP/IP is called.
	I forget at the moment, and am at home.  This one is set up to use a
	special account, which is associated with an ersatz shell allowing only
	lpr and a couple of other harmless commands (sort of like uucico).
	This way, its password can be quasi-common-knowledge.  I recommend you
	follow this practice as well --- I tried it with passwords and the
	user's machine account, but the incessant pop-up windows ran me bananas.

	You may want to customize the command strings and the harunching around
	of argument options, but this should be pretty easy to figure out.

	Charles Buckley                         uucp: mcvax!ethz!ceb
						earn: BUCKLEY@CZHETH5A
						arpa: mcvax!ethz!ceb@uunet.uu.net
						      cb@sail.stanford.edu
	Integrated Systems Laboratory           
	ETH-Zentrum                             

	Postal Address:
	Wiesgasse 9
	CH-8304 Wallisellen     
	Tel: +411 256 52 45

	---- cut here ----
	;;; -*- Mode: LISP; Package: HARDCOPY; Base: 10; Syntax: Common-lisp -*-

	;;
	;;        hardcopy-through-rexec.lisp
	;;
	;;        C. Buckley
	;;        Integrated Systems Laboratory
	;;        Swiss Federal Institute of Technology
	;;        Zurich
	;;
	;;        13 October 1987
	;;
	;;        Since there are no LGP servers for TCP on unix, we simulate
	;;        the same thing using the rexec service, and the lpr
	;;        command.  Ugh.  This version uses a special account called
	;;        lispm, with password conscarcdr, which can only print files.
	;;

	;;
	;;        We here define the protocol to generate the hardcopy 
	;;        stream using rexec.
	;;

	(net:define-protocol :unix-rexec (:hardcopy :byte-stream)
	  (:desirability .8)
	  (:invoke (path)
	   (let* ((host (neti:service-access-path-host path))
		  (args (neti:service-access-path-args path))
		  (options (second args))
		  (plist (locf options))
		  (file-name (get plist :title))
		  (no-banner-page (not (get plist :print-cover-pages)))
		  (copies (get plist :copies))
		  (printer-name (string-downcase (send (send (first args) :name)
						       :string)))
		  (command-string
		    (string-append "lpr "
				   (if printer-name
				       (string-append "-P" printer-name " ") "")
				   (if file-name
				       (string-append "-J \"" (string file-name) "\" ")
				       "")
				   (if no-banner-page "-h " "")
				   (if (and (numberp copies) (> copies 1))
				       (format nil "-\#~d " copies) "")
				   "-C \"" (string host) "\""))
		  (stream (neti:get-connection-for-service path :characters nil)))
	       (unwind-protect
		   (progn
		     (send stream :string-out (string-to-ascii "0"))
		     (send stream :tyo 0)
		     (send stream :string-out (string-to-ascii "lispm"))
		     (send stream :tyo 0)
		     (send stream :string-out (string-to-ascii "conscarcdr"))
		     (send stream :tyo 0)
		     (send stream :string-out (string-to-ascii command-string))
		     (send stream :tyo 0)
		     (send stream :force-output)
		     (if (zerop (send stream :tyi))
			 (progn
			   (send stream :string-out (string-to-ascii "%!"))
			   stream)
			 (progn
			   (error "REXEC error from ~A: ~A" host
				  (ascii-to-string
				    (with-output-to-string (s)
				      (stream-copy-until-eof stream s))))
			   (send stream :close :abort)
			   nil)))))))