AirPrint to any printer (without official AirPrint support) using Ubuntu and iOS

This is an update of my previous AirPrint escapade to get AirPrint working with Ubuntu 12.04 and iOS / OSX using a generic printer. I'm still using the Epson SX600FW and SX610FW family which have both been great to date, I spent an hour updating the config to enable AirPrint compatibility. Read on... 


Setup

• I use an Epson SX610FW which is a network printer connected wirelessly to a WRT-54GL router and my Ubuntu server. This can work with any printer attached to a Ubuntu machine.
• iOS versions 4.0 and above
• OSX 10.6 Snow Leopard and above
• Tested with Ubuntu 12.04 and above, which acts as the AirPrint server

Here's what to do:


1. Add your printer to the Ubuntu server

• Goto System > Administration > Printing & And click Add Printer.
• Select ‘Network Printer’ and 'Find Network Printer'
• For me Ubuntu then automatically found and installed the appropriate driver, your mileage may vary
• Eventually click ‘Apply’ to finish.

 2. Check that CUPS is in installed, if not you will need to install CUPS. You will need to have a PDF filter working correctly. Debian (Ubuntu) seems to provide this out of the box with a CUPS install;
dpkg -s cups | grep Status
sudo apt-get install cups


3. Go into the CUPS interface which should be here: http://localhost:631/admin

Enable the following options:

• Show printers shared by other systems
• Share printers connected to this system
• Allow printing from the Internet
• Allow remote administration
• Allow users to cancel any job (not just their own) 

Do not add your printer to CUPS using this interface, the "share printers connected to this system" does this.

4. Edit the CUPS configuration file;

sudo gedit /etc/cups/cupsd.conf

Add the following lines: 

ServerAlias *

Change the following lines:
Port Localhost:631 to Port 631
BrowseAllow to BrowseAllow All

5. Check that Avahi is installed, if not you will need to install Avahi-daemon;

dpkg -s Avahi-daemon | grep Status

sudo apt-get install avahi-daemon

6. Restart CUPS to get it to publish printer services. (AirPrint will not be using the CUPS-published services, but we will need them to recreate a manual service.)

sudo /etc/init.d/cups restart

7. Generate the AirPrint Avahi service files for CUPS printers. TJ Fontaine has created a great script that automates the creation of the service files see, the actual script is here airprint-generate script.
./airprint-generate.py  


8. Move the generated AirPrint Avahi services files to the Avahi folder;
sudo mv AirPrint-Epson-Stylus-SX600FW.service /etc/avahi/services/AirPrint-Epson-Stylus-SX600FW.service


9. Restart CUPS and Avahi;
sudo /etc/init.d/cups restart
sudo restart avahi-daemon

10. Add two new config files

sudo vi /usr/share/cups/mime/airprint.types
Contents:
#
# "$Id: $"
#
# AirPrint type
image/urf urf string(0,UNIRAST<00>)
#
# End of "$Id: $".
#

sudo vi /usr/share/cups/mime/airprint.convs
Contents:
#
# "$Id: $"
#
# AirPrint
# Updated list with minimal set 25 Sept
image/urf application/pdf 100 pdftoraster
#
# End of "$Id: $".
#



10. Print! on your iPhone/iPad, go into an application (Safari, for example), print, and search for printers. Your new printer definition should be in there.


Kudos to Ryan Finnie for his initial research and TJ Fontaine the great AirPrint services script.. TJ Fontaine's AirPrint services python script is below for reference in case the link dies. Be careful if you copy this, that you do not copy the HTML encoding:

#!/usr/bin/env python

"""
Copyright (c) 2010 Timothy J Fontaine 

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""

import cups, os, optparse, re, urlparse
import os.path
from StringIO import StringIO

from xml.dom.minidom import parseString
from xml.dom import minidom

import sys

try:
    import lxml.etree as etree
    from lxml.etree import Element, ElementTree, tostring
except:
    try:
        from xml.etree.ElementTree import Element, ElementTree, tostring
        etree = None
    except:
        try:
            from elementtree import Element, ElementTree, tostring
            etree = None
        except:
            raise 'Failed to find python libxml or elementtree, please install one of those or use python >= 2.5'

XML_TEMPLATE = """



	_ipp._tcp
	_universal._sub._ipp._tcp
	631
	txtvers=1
	qtotal=1
	Transparent=T
	URF=none

"""

#TODO XXX FIXME
#ty=AirPrint Ricoh Aficio MP 6000
#Binary=T
#Duplex=T
#Copies=T


DOCUMENT_TYPES = {
    # These content-types will be at the front of the list
    'application/pdf': True,
    'application/postscript': True,
    'application/vnd.cups-raster': True,
    'application/octet-stream': True,
    'image/urf': True,
    'image/png': True,
    'image/tiff': True,
    'image/png': True,
    'image/jpeg': True,
    'image/gif': True,
    'text/plain': True,
    'text/html': True,

    # These content-types will never be reported
    'image/x-xwindowdump': False,
    'image/x-xpixmap': False,
    'image/x-xbitmap': False,
    'image/x-sun-raster': False,
    'image/x-sgi-rgb': False,
    'image/x-portable-pixmap': False,
    'image/x-portable-graymap': False,
    'image/x-portable-bitmap': False,
    'image/x-portable-anymap': False,
    'application/x-shell': False,
    'application/x-perl': False,
    'application/x-csource': False,
    'application/x-cshell': False,
}

class AirPrintGenerate(object):
    def __init__(self, host=None, user=None, port=None, verbose=False,
        directory=None, prefix='AirPrint-', adminurl=False):
        self.host = host
        self.user = user
        self.port = port
        self.verbose = verbose
        self.directory = directory
        self.prefix = prefix
        self.adminurl = adminurl
        
        if self.user:
            cups.setUser(self.user)
    
    def generate(self):
        if not self.host:
            conn = cups.Connection()
        else:
            if not self.port:
                self.port = 631
            conn = cups.Connection(self.host, self.port)
            
        printers = conn.getPrinters()
        
        for p, v in printers.items():
            if v['printer-is-shared']:
                attrs = conn.getPrinterAttributes(p)
                uri = urlparse.urlparse(v['printer-uri-supported'])

                tree = ElementTree()
                tree.parse(StringIO(XML_TEMPLATE.replace('\n', '').replace('\r', '').replace('\t', '')))

                name = tree.find('name')
                name.text = 'AirPrint %s @ %%h' % (p)

                service = tree.find('service')

                port = service.find('port')
                port_no = None
                if hasattr(uri, 'port'):
                  port_no = uri.port
                if not port_no:
                    port_no = self.port
                if not port_no:
                    port_no = cups.getPort()
                port.text = '%d' % port_no

                if hasattr(uri, 'path'):
                  rp = uri.path
                else:
                  rp = uri[2]
                
                re_match = re.match(r'^//(.*):(\d+)(/.*)', rp)
                if re_match:
                  rp = re_match.group(3)
                
                #Remove leading slashes from path
                #TODO XXX FIXME I'm worried this will match broken urlparse
                #results as well (for instance if they don't include a port)
                #the xml would be malform'd either way
                rp = re.sub(r'^/+', '', rp)
                
                path = Element('txt-record')
                path.text = 'rp=%s' % (rp)
                service.append(path)

                desc = Element('txt-record')
                desc.text = 'note=%s' % (v['printer-info'])
                service.append(desc)

                product = Element('txt-record')
                product.text = 'product=(GPL Ghostscript)'
                service.append(product)

                state = Element('txt-record')
                state.text = 'printer-state=%s' % (v['printer-state'])
                service.append(state)

                ptype = Element('txt-record')
                ptype.text = 'printer-type=%s' % (hex(v['printer-type']))
                service.append(ptype)

                pdl = Element('txt-record')
                fmts = []
                defer = []

                for a in attrs['document-format-supported']:
                    if a in DOCUMENT_TYPES:
                        if DOCUMENT_TYPES[a]:
                            fmts.append(a)
                    else:
                        defer.append(a)

                if 'image/urf' not in fmts:
                    sys.stderr.write('image/urf is not in mime types, %s may not be available on ios6 (see https://github.com/tjfontaine/airprint-generate/issues/5)%s' % (p, os.linesep))

                fmts = ','.join(fmts+defer)

                dropped = []

                # TODO XXX FIXME all fields should be checked for 255 limit
                while len('pdl=%s' % (fmts)) >= 255:
                    (fmts, drop) = fmts.rsplit(',', 1)
                    dropped.append(drop)

                if len(dropped) and self.verbose:
                    sys.stderr.write('%s Losing support for: %s%s' % (p, ','.join(dropped), os.linesep))

                pdl.text = 'pdl=%s' % (fmts)
                service.append(pdl)

                if self.adminurl:
                    admin = Element('txt-record')
                    admin.text = 'adminurl=%s' % (v['printer-uri-supported'])
                    service.append(admin)
                
                fname = '%s%s.service' % (self.prefix, p)
                
                if self.directory:
                    fname = os.path.join(self.directory, fname)
                
                f = open(fname, 'w')

                if etree:
                    tree.write(f, pretty_print=True, xml_declaration=True, encoding="UTF-8")
                else:
                    xmlstr = tostring(tree.getroot())
                    doc = parseString(xmlstr)
                    dt= minidom.getDOMImplementation('').createDocumentType('service-group', None, 'avahi-service.dtd')
                    doc.insertBefore(dt, doc.documentElement)
                    doc.writexml(f)
                f.close()
                
                if self.verbose:
                    sys.stderr.write('Created: %s%s' % (fname, os.linesep))

if __name__ == '__main__':
    parser = optparse.OptionParser()
    parser.add_option('-H', '--host', action="store", type="string",
        dest='hostname', help='Hostname of CUPS server (optional)', metavar='HOSTNAME')
    parser.add_option('-P', '--port', action="store", type="int",
        dest='port', help='Port number of CUPS server', metavar='PORT')
    parser.add_option('-u', '--user', action="store", type="string",
        dest='username', help='Username to authenticate with against CUPS',
        metavar='USER')
    parser.add_option('-d', '--directory', action="store", type="string",
        dest='directory', help='Directory to create service files',
        metavar='DIRECTORY')
    parser.add_option('-v', '--verbose', action="store_true", dest="verbose",
        help="Print debugging information to STDERR")
    parser.add_option('-p', '--prefix', action="store", type="string",
        dest='prefix', help='Prefix all files with this string', metavar='PREFIX',
        default='AirPrint-')
    parser.add_option('-a', '--admin', action="store_true", dest="adminurl",
        help="Include the printer specified uri as the adminurl")
    
    (options, args) = parser.parse_args()
    
    # TODO XXX FIXME -- if cups login required, need to add
    # air=username,password
    from getpass import getpass
    cups.setPasswordCB(getpass)
    
    if options.directory:
        if not os.path.exists(options.directory):
            os.mkdir(options.directory)
    
    apg = AirPrintGenerate(
        user=options.username,
        host=options.hostname,
        port=options.port,
        verbose=options.verbose,
        directory=options.directory,
        prefix=options.prefix,
        adminurl=options.adminurl,
    )
    
    apg.generate()