[sane-devel] Is there any plan to support Web Devices Services (WDS) protocol?

Tue Feb 6 16:10:25 UTC 2018

Hi all,

I found http://ws4d.org/dpws-explorer/ . It has a linux version, it can
help a bit with device detection and browse properties while developing a
proper scan software.
Here <https://sourceforge.net/projects/ws4d-javame/> is a java
implementation of the DPWS standard, and here
<http://trac.e-technik.uni-rostock.de/projects/ws4d-gsoap> a C/C++ one.

However, I found another batch of documentation of the standard, so
developing a simple working implementation targeted mainly to scan
capabilities isn't going to be difficult.

The C/C++ library posted above might be not suitable for sane backend
implementation, I don't think sane devs would allow adding such a large
gen-purpose dependency to codebase, and a lightweight implementation is
better IMHO.

Il giorno mar 6 feb 2018 alle ore 00:05 Patrick Roncagliolo <
ronca.pat at gmail.com> ha scritto:

> Hi,
>
> you can find a basic implementation of a WSD discovery scanner here:
> https://github.com/roncapat/WSD-python
>
> Here is a sample output (it detects a response from my MB2350):
>
> EndPoint Reference Address:
> urn:uuid:00000000-0000-1000-8000-f4813944662e
> Implemented Types:
> wsdp:Device
> wprt:PrintDeviceType
> wscn:ScanDeviceType
> Transport addresses:
> http://192.168.1.5:80/wsd/pnpx-metadata.cgi
>
> Basically, it retrieves an unique identifier, the capabilities of the
> devices (MB2350 is both printer and scanner), and an HTTP address for later
> use.
> More coming. Understanding the protocol with an easy language as Python
> with no API constraints helps to bootstrap a working implementation, but
> ideally the next step would be a true backend implementation.
>
> Patrick Roncagliolo
>
>
> Il giorno lun 5 feb 2018 alle ore 16:25 Patrick Roncagliolo <
> ronca.pat at gmail.com> ha scritto:
>
>> Hi Till,
>> WSD came in with Windows Vista IIRC.
>> It is HTTP/XML based, so yeah, it works only on network, in fact my canon
>> maxify uses an entirely different protocol on USB (similar, if not equal,
>> to the BJNP network protocol used by Canon for basic Linux LAN support).
>> It defines a discovery protocol, a scan service, a print service, but
>> probably there are more, unrelated with the printer/multifunction/scanner
>> world (I started today to dig the docs).
>>
>> By the way, I managed to fix the script found in the github repo I
>> linked, and maybe the first step for me to get comfortable with the
>> protocol will be to play a bit more from python, extending as much as I can
>> the short script as a more complete CLI tool with discovery support and all
>> the possible options. Then, I could manage to reimplement the protocol as a
>> sane backend, which I think is a bit more hard (I need to study sane api
>> first).
>>
>> Beware I'm a student with not-so-much spare time, but I'm interested in
>> learning something new and get my canon working at best, and obviously
>> contribute as much as I can. I'd like to add or expand wireshark dissectors
>> for WSD and BJNP too. We'll see how much I can do.
>>
>> NB. if in the coming days I start a github repo for a WSD python
>> playground, I'll share here the link.
>>
>> Here are a few links:
>> -WS-Discovery (full spec)
>> http://specs.xmlsoap.org/ws/2005/04/discovery/ws-discovery.pdf
>> -WS-Print (at the bottom of the page there are links to all print & scan
>> XML schemas and tech specifications)
>> https://docs.microsoft.com/en-us/windows-hardware/drivers/print/ws-print-v1-1
>> -WS-Print 2.0 (only printing? 3d printers? have no time to check)
>> http://go.microsoft.com/fwlink/p/?LinkId=534008
>>
>>
>>
>>
>> Il giorno lun 5 feb 2018 alle ore 15:54 Till Kamppeter <
>> till.kamppeter at gmail.com> ha scritto:
>>
>>> On 02/05/2018 01:32 PM, Patrick Roncagliolo wrote:
>>> > WDS is a protocol based on http connection with devices such as
>>> > scanners, printers and so on. Most of the work is based on a bunch of
>>> > XML schemas, that are publicly available on MSDN. Searched a lot, but
>>> > for Linux I only found this (https://github.com/al42and/WSDolefuls),
>>> > that fails to parse the scanner response, but succeeds to start the
>>> scan
>>> > job.
>>> > I tried to search around SANE for WDS support, but I understood there
>>> > isn't.
>>> >
>>> > Is there a technical motivation behind the lack of support for WDS? or
>>> > it's just not the top priority? Could it be possible to create a
>>> backend
>>> > for this protocol? A lot of Canon printers would work like a charm with
>>> > a single good implementation, and I think it would be the same with a
>>> > lot of modern hardware. I could try to start a simple implementation if
>>> > someone instructs me with the basics of the SANE internal API for
>>> > backends and working principles, I'm a student with (not much) free
>>> time
>>> > and it could be great to help a bit (and learn something) if possible.
>>> >
>>>
>>> This looks like a second driverless (meaning no device/model-specific
>>> software or data (aka driver) required) scanning method after PWG's
>>> (Printer Working Group, http://www.pwg.org/) IPP Scanning which I
>>> mentioned in another post on this list.
>>>
>>> It seems that WDS exists already for longer time and is already
>>> established, so that there are actually several scanners using it. Am I
>>> right? Which manufacturers are participating? Does it only work on
>>> network devices? Or only on USB? Does it only work on printer/scanner MF
>>> devices or also on stand-alone scanners?
>>>
>>> Patrick, it would be great if you could make a SANE module for that.
>>> Another step to making a scanner as easy to connect under Linux as a USB
>>> stick. Also great for MF devices which happily print with PWG's
>>> driverless IPP printing but do not support IPP scanning.
>>>
>>>     Till
>>>
>>> --
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>>
>>
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