#!/bin/sh
#
# Usage:     pap job user title copies options [filename]
#            pap
#
# Important: This backend supports device discovery -- just call it without
#            parameters to see whether it works correctly on your system.
#
# Main use:  CUPS backend to drive AppleTalk printers. Tested with CUPS
#            1.1.14/1.1.15/1.1.19
#
# Notes:     Device URIs have to have the following format (special chars
#            in URL encoding): pap://zone/printername/printertype
#            Normally you shouldn't care about that since the backend lists
#            all available devices correctly formatted when asked by the
#            CUPS scheduler.
#            Don't forget to adjust $devicetypes and $formfeed to your needs!
#            When used with Darwin 7.0 (MacOS X 10.3.x) you might want to
#            change the shell to /bin/bash in the first line due to problems
#            with the encoding routines for the device uri (perl -e call)
#
#############################################################################
#
# author:    Thomas Kaiser <mailto:Thomas.Kaiser@phg-online.de>
# url:       http://users.phg-online.de/tk/CUPS/backend/pap
# date:      08 Jan 2004 (v0.1.3)
#
#############################################################################
#
# Changes
#
# 0.1.3: - query AppleTalk devices by default for their "Product name" to
#          let CUPS assign the correct PPD automatically (this is achieved
#          by setting FullDeviceDiscovery=TRUE)
#        - set the default netatalk installation path back to /usr/bin
#        - set a timeout value of 15 seconds when querying printers for
#          their "Product name"
#        - massive performance improvement in larger networks with many
#          zones when doing device discovery while $FullDeviceDiscovery
#          set to TRUE (due to parallelizing the queries)
#
# 0.1.2: - fix the inability to deal with printers with slashes in their 
#          names
#        - report wrong netatalk installation dir --> ${NetatalkBinDir}
#        - minor documentation improvements
#
# 0.1.1: - fix some documentation errors and default values
#
# 0.1.0: - first official release (22 Mar 2003)
#
#############################################################################
#
# To Do:
#
# - optionally send pagecount queries to get exakt accounting info
#
#############################################################################
#
# Non-Warranty: 
# This script comes with absolutely no warranty.
#
# Use at your own risk!
#
#############################################################################
#
# Customizable settings:
#
# The devicetype variable specifies for which devices to look for (eg.
# LaserWriter, DeskWriter, ImageWriter). If you want to lookup more than 
# one device at a time, write them separated with colons, ie. 
#
#     devicetypes="LaserWriter:DeskWriter"
#
# For all devicetypes use "=" instead. But be warned: this will also find
# macs, servers, serial numbers and the like
 
devicetypes="LaserWriter"

# specify whether or not to send an additional form feed (DeskWriters 
# seem to need this. TRUE means send the ff

formfeed=FALSE

# When you want to use this with Netatalk, then specify the path to
# the $BINDIR (do a search for nbplkup, eg.). You might also want to set
# $FullDeviceDiscovery to TRUE to let CUPS guess the correct PPD for the
# devices by asking them for their "Product" name...
# Additionally you can let the backend collect exact pagecounts from
# PostScript printers that correctly implement a back channel (answering
# the backend's questions). If you use dumb AppleTalk print servers do
# NOT set this option
#
# Note: This last option is still not implemented

NetatalkBinDir=/usr/bin
FullDeviceDiscovery=TRUE
ExaktPageCount=FALSE            # currently without effect

#############################################################################

main()
{
	# Processing the CUPS request. There exist 2 possibilities: Either CUPS
	# is asking us about device capabilities we can provide or it want us to
	# handle a print request and send the print job to a specific device
	
	CollectAccountingData "$@"
	PrepareRequest

	# No arguments means show available devices and exit...
	
	if test $# = 0; then
	
		echo "network ${protocol} \"Unknown\" \"AppleTalk Devices via ${protocol}\""
		
		LookupDevices | sort | uniq
	
		exit 0
	
	fi
	
	# Handle the print request. First check whether the device is available

	if PrinterAvailable "${PrinterName}" ; then

		type=`GetAppleTalkType "${PrinterName}"`
	
		if test $# = 5; then
		
			# Get print file from stdin; copies have already been handled...

			NotifyCUPS "INFO: Sending to ${PrinterName}"
			cat | PrintAndAccount "${PrinterName}"
			NotifyCUPS "PAGE: 1 1"    # TO DO: send pagecount queries
		
		else

			# Print file is on command-line and we have to handle copies ourselve...
		
			SpoolFile=$6
		
			while [ ${NeededCopies} -gt 0 ]; do

				ActualCopy=`expr $4 + 1 - ${NeededCopies}`
				NotifyCUPS "INFO: Sending copy ${ActualCopy} to ${PrinterName}"
				
				PrintAndAccount "${PrinterName}" < "${SpoolFile}"
				NotifyCUPS "PAGE: ${CountOfCopies} $4"    # TO DO: send pagecount queries
				
				NeededCopies=`expr ${NeededCopies} - 1`
				
			done
			
		fi
	
		# Eventually send an additional form feed (some DeskWriters seem to 
		# need that)
	
		if [ "X${type}" = "XDeskWriter" ]; then 
			test "X${formfeed}" = "XTRUE" && printf "\f" | PrintAndAccount "${PrinterName}"
		fi

	else

		NotifyCUPS "ERROR: Unable to get printer status for \"${PrinterName}\""
		exit 1

	fi
}

PrepareRequest()
{
	# How are we called?

	protocol=`basename $0`

	# Let's have a look whether we are using Netatalk's or Darwin's 
	# AppleTalk implementation
		
	case `uname -s` in
	Darwin)
		ZoneLookup="/usr/bin/atlookup -z"
		PrinterAvailable()
			{
			/usr/bin/atstatus "$1" >/dev/null
			}
		PrintAndAccount()
			{
			/usr/bin/atprint "$1"
			}
		NBPLookup()
			{
			/usr/bin/atlookup -a "$1" | grep -v "^#  Found"
			}
		ATPErrMsg="ATPsndreq\:\ Operation\ timed\ out"
		CheckProductName()
			{
			echo "Unknown"
			}
		TotalPages()
			{
			echo ${CUPS_PrintSettingsPMTotalBeginPages}
			}
		;;
	*)
		# test the path of ${NetatalkBinDir}
		if [ ! -x "${NetatalkBinDir}/papstatus" ]; then
			echo "ERROR: Netatalk tools not found in \"${NetatalkBinDir}\"" >&2
			exit 1
		fi

		ZoneLookup="${NetatalkBinDir}/getzones"
		PrinterAvailable()
			{
			${NetatalkBinDir}/papstatus -p "$1" >/dev/null
			}
		PrintAndAccount()
			{
			${NetatalkBinDir}/pap -p "$1"
			}
		NBPLookup()
			{
			${NetatalkBinDir}/nbplkup "$1" | \
			perl -ne 'chomp; next if /^$/; m|^\s+(.+)\s+\d+\.\d+:|; my $entry = $1; $entry =~ s/\s+$//; print "$entry\n"'
			}
		ATPErrMsg="atp_rresp\:\ Connection\ timed\ out"
		CheckProductName()
			{
			# We'll try to ask the printer for its so called
			# "Product name" to let CUPS automatically assign
			# the right PPD file for the printer

			GuessedDeviceType="Unknown"

			if [ "$2" = "LaserWriter" -a "${FullDeviceDiscovery}" = "TRUE" ]; then
				if ${NetatalkBinDir}/papstatus -p "$1:$2@$3" >/dev/null 2>&1
					then
					DeviceLookup=`echo -e "%%?BeginFeatureQuery: *Product\nstatusdict begin\nproduct print\nend\n%%?EndFeatureQuery: Unknown\n%%EOF" | ${NetatalkBinDir}/timeout -s HUP 15 -- ${NetatalkBinDir}/pap -p "$1:$2@$3" | sed 's|^\"(||;s|)\"$||;'`
					if [ -n "${DeviceLookup}" ]; then
						GuessedDeviceType="${DeviceLookup}" 
					fi
				fi
			fi

			echo "${GuessedDeviceType}"
			}
		TotalPages=1
		;;
	esac

	# redefine the internal field separator to parse the zone list 
	# correctly
	
IFS="
"
}

GetAppleTalkType()
{
	echo "$1" | cut -d: -f2 | cut -d@ -f1
}

LookupDevices()
{
	# Fetch the zone list and do a lookup in every single zone for occurences
	# of type $devicetype
	
	zonelist="`GetZoneList`"
	
	# get a list of AppleTalk Devicetypes to look for
	OIFS=$IFS
	IFS=":"
	set ${devicetypes}
	IFS=$OIFS

	for devicetype in $@; do
		echo "${zonelist}" | while read zone; do
			NBPLookup "=:${devicetype}@${zone}" | while read nbpentry ; do
				GetPrinterProperties "${nbpentry}" "${zone}" "${protocol}" &
			done &
		done
	done
}

GetZoneList()
{
	# check whether we have to deal with zones
	
	eval ${ZoneLookup} >/dev/null
	
	if [ $? -eq 0 ]; then     # okay, zones are available
		eval ${ZoneLookup} 2>&1 | sed "s|${ATPErrMsg}|*|;"
	else
		echo '*'
	fi
}

GetPrinterProperties()
{
	name=`echo $1 | awk -F: '{print $1}'`
	type=`echo $1 | awk -F: '{print $2}'`
	model=`CheckProductName "${name}" "${type}" "$2"`
	echo -e "network $3://`EncodeDeviceURI "$2"`/`EncodeDeviceURI "${name}"`/`EncodeDeviceURI "${type}"` \"${model}\" \"${name}@${zone} ($3)\""
}

EncodeDeviceURI()
{
	# We'll have to quote the names with an URL encoding (RFC 2396)

	echo "$@" | perl -ple 's|([^\w=\-:@])|sprintf( "%%%02x", ord( $1))|ge'
}

DecodeDeviceURI()
{
	# Decode the Device-URI
	
	echo "$@" | awk -F/ '{print $4 ":" $5 "@" $3}' | perl -ple 's/%([0-9A-Fa-f]{2})/chr(hex($1))/eg'
}

NotifyCUPS ()
{
	# sending message on stderr to keep CUPS informed
	
	echo -e "$*" >&2
}

CollectAccountingData ()
{
	PrinterName=`DecodeDeviceURI ${DEVICE_URI}`
        Owner="$2"
        Title="$3"
        NeededCopies=$4

	# parse the options passed from CUPS
	eval ParseCUPSOptions $5
}

ParseCUPSOptions()
{
	# We parse the CUPS options, delete occurences of "com.apple.print" in
	# their names, prepend the variable names with "CUPS_", define
	# them as variables and export them

	i="com\.apple\.print\."
        while [ $# -ge 1 ]; do
		VarName=`echo $1 | cut -d"=" -f1 | sed "s|^$i||g;s|\.[nb]\.$||g;s|\.||g"`
		VarValue=`echo $1 | cut -d"=" -f2 | sed "s|\ |\\\\\ |g"`
		eval CUPS_${VarName}=${VarValue}
		eval export CUPS_${VarName}
                shift
        done
}

#############################################################################
#
# Let's start to process the CUPS requests

main "$@"
exit 0