sane-airscan -- SANE backend for AirScan (eSCL) and WSD document scanners

Similar to how most modern network printers support "driverless" printing, using the universal vendor-neutral printing protocol, many modern network scanners and MFPs support "driverless" scanning.

Driverless scanning comes in two flavors:

• Apple AirScan or AirPrint scanning (official protocol name is eSCL)
• Microsoft WSD, or WS-Scan (term WSD means "Web Services for Devices)

This backend implements both protocols, choosing automatically between them. It was successfully tested with many devices from Brother, Canon, Dell, Kyocera, Lexmark, Epson, HP, OKI, Panasonic, Pantum, Ricoh, Samsung and Xerox both in WSD and eSCL modes.

For eSCL devices, Apple maintains a comprehensive list of compatible devices, but please note, this list contains not only scanners and MFP, but pure printers as well.

This backend doesn't require to install and doesn't conflict with vendor-provided proprietary software like ScanGear from Canon, HPLIP from HP and so on.

Features

1. One backend for two different protocols, eSCL and WSD
2. Automatic and manual device discovery and configuration
3. Scan from platen and ADF, in duplex and simplex modes, multi-page scan from ADF supported as well
4. Scan in color and gray scale modes
5. Line-by-line image unpacking, for low memory footprint
6. The cancel operation is as fast as possible, depending on your hardware
7. Both IPv4 and IPv6 are supported

Compatibility

Any eSCL and WSD capable scanner expected to work. Here is a list of devices that were actually tested. If you have success with a scanner not included into this list, please let me know.

In most cases, devices were tested with network connection. However, most (all?) of the eSCL devices will also work over USB, if IPP-over-USB daemon is installed on your computer. WSD-only devices cannot be used with the IPP-over-USB daemon.

Currently, there is a choice of two IPP-over-USB implementations:

• ippusbxd, which comes with some distros
• ipp-usb, a modern replacement of the ippusbxd. The ipp-usb works better, binary packages available for many popular distros (see link from a project page).

Legend:

• Yes - device works perfectly
• No - protocol not supported by device
• ? - device works with sane-airscan, but protocol is not reported by user
• Space - author has no information on this mode/device combination

^[1]: this device requires manual activation of AirPrint scanning on its web console: Home->Menu->Preferences->Network->TCP/IP Settings->Network Link Scan Settings->On.

^[2]: WS-Scan needs to be manually enabled on this device: Home->Menu->Preferences->Network->TCP/IP Settings->WSD Settings->Use WSD Scanning->ON

^[3]: this device is USB-only, but it works well with the IPP-over-USB daemon.

^[4]: by default, WS-Scan is disabled on this device and needs to be enabled before use: open web console, Click [Settings/Registration], Click [Network Settings]->[TCP/IP Settings], Click [Edit] in [WSD Settings], enable [Use WSD Scanning] checkbox, Click [OK]

^[5]: this device requires manual action on its front panel to initiate WSD scan: Send->WSD Scan->From Computer

^[6]: when low in memory, this device may scan at 400 DPI instead of requested 600 DPI. As sane-airscan reports image parameters to SANE before actual image is received, and then adjust actual image to reported parameters, image will be scaled down by the factor 2/3 at this case. Lower resolutions works well.

^[7]: by default, WS-Scan is disabled on this device and needs to be enabled before use: open web console, Click [Configuration], click [Initial Settings] under [Scanner], and then set [Prohibit WSD Scan Command] to [Do not Prohibit] (from http://support.ricoh.com/bb_v1oi/pub_e/oi_view/0001047/0001047003/view/scanner/int/0095.htm)

^[8]: with old firmware (tested with V4.00.01.04 APR-09-2013) ADF scan causes device reboot. Firmware update helps, version V4.00.02.20 MAY-27-2020 known to work.

^[8]: eSCL needs to be manually enabled on this device: System-settings->Network settings->Airprint settings->Airscan

^[9]: Scanning remotely and with IPP-over-USB active is disabled by default. In the Embedded Web Server: Settings->Security->Administrator Settings->Enable Scan from a Computer or Mobile Device->Apply

Distros that come with sane-airscan

The following distros (in alphabetical order) include sane-airscan officially:

• ALT Linux (Sisyphus and p9)
• Arch Linux (in extra repository)
• Debian 10+
• Fedora 32+
• NixOS
• Ubuntu 20.10+

This list is constantly growing and may be very incomplete.

Also, sane-airscan works on BSD and included into FreeBSD, NetBSD and OpenBSD ports.

Installation from pre-build binaries

If you use one of the following Linux distros:

• Debian (9.0 and 10)
• Fedora (29, 30, 31 and 32)
• openSUSE (Leap and Tumbleweed)
• Ubuntu (16.04, 18.04, 19.04, 19.10 and 20.04)

Follow this link, where you will find packages and very detailed installation instructions.

Note, after a fresh build this link sometimes takes too long to update, so if you encounter "Resource is no longer available!" problems, there is a direct link to repositories: https://download.opensuse.org/repositories/home:/pzz/

I strongly recommend you to choose "Add repository and install manually" option rather that "Grab binary packages directly", because it will enable automatic updates of the sane-airscan package.

Linux Mint users may use Ubuntu packages:

• Linux Mint 18.x - use packages for Ubuntu 16.04
• Linux Mint 19.x - use packages for Ubuntu 18.04
• Linux Mint 20.x - use packages for Ubuntu 20.04

Big thanks to openSUSE Build Service for providing package build infrastructure.

If your distro is not listed, see Installation from sources section below.

Installation from sources

Install required libraries - Fedora and similar

As root, execute the following commands:

dnf install gcc git make pkgconf-pkg-config
dnf install avahi-devel
dnf install libxml2-devel
dnf install libjpeg-turbo-devel libpng-devel
dnf install gnutls-devel
dnf install sane-backends-devel

Install required libraries - Ubuntu, Debian and similar

As root, execute the following commands:

apt-get install gcc git make pkg-config
apt-get install libavahi-client-dev
apt-get install libxml2-dev
apt-get install libjpeg-dev libpng-dev
apt-get install libsane-dev
apt-get install gnutls-dev

Download, build and install sane-airscan

git clone https://github.com/alexpevzner/sane-airscan.git
cd sane-airscan
make
make install

Contribution

All contributions are welcome and greatly appreciated, assuming the following:

1. Feature that you propose has a general interest for many people
2. Your code is well-formatted and has a good quality

Please note, this project has two branches:

• stable branch: https://github.com/alexpevzner/sane-airscan
• development branch: https://github.com/alexpevzner/sane-airscan-unstable

Stable branch accepts mostly bug fixes and minor features with small change in code base. Major features should be contributed into the development branch.

Paid consulting

If your business depends on my project, and you require any specific feature not currently implemented here, you may consider contracting me on a paid basis.

PVS-Studio

PVS-Studio is a static code analyser, supporting C, C++, C# and Java.

Once upon a time I was chatting with its authors in Russian software development forum and told them, that if their tool will find something interesting in my code, I will put a reference to their project here.

Their tool actually found a couple real bugs, so I had to fulfill my promise :-)

Now I regularly test this code with PVS-Studio, and it really helps. Their product is not free, but they offer free licenses for open source projects.

Reporting bugs

To report a bug, please create a new GitHub issue

To create a helpful bug report, please perform the following steps:

1. Enable protocol trace in the sane-airscan, by adding the following entries into the configuration file
   (/etc/sane.d/airscan.conf):

[debug]
trace = ~/airscan/trace ; Path to directory where trace files will be saved

You may use an arbitrary directory path, assuming you have enough rights to create and write this directory. The directory will be created automatically.

2. Reproduce the problem. Please, don't use any confidential documents when problem is being reproduces, as their content will be visible to others.

3. Explain the problem carefully

4. In the directory you've specified as the trace parameter, you will find two files. Assuming you are using program xsane and your device name is "Kyocera MFP Scanner", file names will be "xsane-Kyocera-MFP-Scanner.log" and "xsane-Kyocera-MFP-Scanner.tar". Please, attach both of these files to the new issue.

References

The eSCL protocol is not documented, but this is simple protocol, based on HTTP and XML, easy for reverse engineering. There are many Internet resources around, related to this protocol, and among others I want to note the following links:

• kno10/python-scan-eSCL - a tiny Python script, able to scan from eSCL-compatible scanners
• SimulPiscator/AirSane - this project solves the reverse problem, converting any SANE-compatible scanner into eSCL server. Author claims that it is compatible with Mopria and Apple clients
• markosjal/AirScan-eSCL.txt - document, describing eSCL protocol, based on reverse engineering. Not complete and not always accurate, but gives the good introduction