ipp.el -- Emacs Lisp implementation of the Internet Printing Protocol

This Emacs package provides a partial implemention of the client component of the Internet Printing Protocol (IPP). IPP was intended to replace the LPD protocol for interacting with network printers. It specifies mechanisms for “driverless printing” (submitting and cancelling jobs), queue monitoring and querying printer capabilities. More recent versions of the standard are called “IPP Everywhere”.

You can find out whether a device is IPP-capable by trying to telnet to port 631. If it accepts the connection it probably understands IPP. You then need to discover the path component of the URI, for example by reading the documentation, by looking through the menus via the front panel or the printer's HTTP interface, or by analyzing DNS Service Discovery (Bonjour) network traffic.

Tested with or reported to work on the following devices:

• Tektronix Phaser 750, with a URI of the form "ipp://host:631/" (empty path component)

• TOSHIBA e-STUDIO3005A, with a URI of the form "ipp://host:631/" (empty path component)

• HP Laserjet 4000, with a path component of "/ipp/port1"

• HP Color LaserJet MFP M477fdw

• Lexmark E460dn, with an empty path component

• Lexmark MS312dn with a path component of "/ipp/print" (IPP URI of the form "ipp://10.0.0.1:631/ipp/print" or "ipps://10.0.0.1:443/ipp/print")

• Brother DCP-1610W, with an empty path component

• Xerox Document Centre 460 ST, with empty path component

• Epson AL-MX300 and AL-M310DN with a path component of "/Epson_IPP_Printer" (IPP URI of the form "ipp://10.0.0.1/Epson_IPP_Printer" or "ipps://10.0.0.1:443/Epson_IPP_Printer")

• Xerox Document Centre 460 ST, with empty path component.

• CUPS printer spooler.

Installation

Install via the MELPA package archive by including the following in your Emacs initialization file (.emacs.el or init.el):

(require 'package)
(add-to-list 'package-archives '("melpa" . "https://stable.melpa.org/packages/") t)

then saying

 M-x install-package RET ipp

To install manually, place the file ipp.el in a directory on your load-path and add the following to your Emacs initialization file:

(require 'ipp)

Usage

Print a file using M-x ipp-print. This will prompt you for a file name (which should be in a format understood natively by the printer, such as PDF), and the URI of the printer. The URI should be of the form

ipp://10.0.0.1:631/ipp/port1   (unencrypted connection on port 631, path="/ipp/port1")
ipps://10.0.0.1/               (TLS connection on port 631, empty path component)

You can specify a default value for the printer URI by customizing variable ipp-default-printer:

`M-x customize-group RET ipp-printing RET`

There are also two functions for querying the capability of the device (ipp-get-attributes) and examining its queue (ipp-get-jobs). Until I write display code for these functions you will have to call them from an IELM buffer to examine their return value.

ELISP> (ipp-get-attributes "ipps://127.0.0.1:631/")

Background

The IPP network protocol is based on HTTP/1.1 POST requests (or potentially HTTP/2 in the most recent versions, though this library does not support it), using a special application/ipp MIME Content-Type. The data is encoded using simple marshalling rules.

The Internet Printing Protocol is described in RFC 8011, and previously RFC numbers 3382, 3381, 2911, 2568, 2566, 2565. The Printer Working Group maintain a page at

https://www.pwg.org/ipp/

Eventually it would be nice to modify the Emacs printing API to support this type of direct printing, so that a user could set ps-printer-name to "ipp://modern-printer:631/" or "lpd://ancient-printer/queue" (it would be easy to write a package similar to this one implementing the LPD protocol at the network level; the LPD protocol is very simple).

Thanks to Vinicius Jose Latorre and Marc Grégoire for patches and to Colin Marquardt and Andrew Cosgriff for help in debugging.

The latest version of this package should be available from

<https://github.com/emarsden/ipp-el>