[Qgis-developer] [Qgis-user] A discussion: is qgis still affordable in Europe if it violate the Inspire directive ?

Jürgen E. Fischer jef at norbit.de
Sun Jun 8 03:16:22 PDT 2014


[most of this is already in the ticket - I recapture here]

Hi Mats,

On Sun, 08. Jun 2014 at 09:07:33 +0200, Mats Elfström wrote:
> Now tell me, is it a deliberate design choice not to make Qgis server OGC
> compliant, and if so, why?

QGIS server wasn't intentionally made incompliant.  It was just extended.

I don't know if any clients actually have problems with the service it offers,
but those extensions actually make the validation of the GetCapabilities
response fail.  But the validation is a expensive process anyway and therefore
most clients skip to validate and just use the response as is.  That should
work fine and so the invalidity of the response is probably a non-issue for
most applications - and therefore went unnoticed (by wms clients and us) for
quite a while.

But extending the GetCapabilities response it also covered by the spec, so that
itself isn't a problem either.   It's just that the response needs to include
another pointer to a document that describes the extensions and make validating
the response document possible again.  Only that part was missing in QGIS.

Currently QGIS server offers GetLegendGraphic, GetStyles and GetPrint as
extended requests.  I'm not an XML expert (the GetCapabilities response is in
XML), but including such an reference document seems to always introduce a new
namespace and therefore extended requests always need to have a (namespace)
prefix.  So eg. GetPrint should be qgis:GetPrint instead.  That's currently
also not the case.

So to fix this, we need to add prefixes, but that in turn might break clients
that currently rely on the prefixless version.  I don't know if there are any -
but it makes me hesitant to change it.

Anyway, the spec apparently allows to have the OGC schema at a different spot
and doesn't clearly state that the copy needs to be identical - just probibits
that "the normative content of the schema is changed".   The current solution
(which admittly has a smell) is that there is a document on qgis.org, that the
qgis server response references instead of the OGC original and that document
includes the original schema (by reference) and adds the extended requests the
usual way, but in the process avoiding the prefix.

If that complies with the quote above, we're fine now, although we might be
bending the spec a little - but we're not breaking any existing clients and
have validity now.

We can come up with something better once we more about affected clients.  I
suppose the actual players in the qgis server field will join next week.


Jürgen 

-- 
Jürgen E. Fischer         norBIT GmbH               Tel. +49-4931-918175-31
Dipl.-Inf. (FH)           Rheinstraße 13            Fax. +49-4931-918175-50
Software Engineer         D-26506 Norden               http://www.norbit.de
QGIS PSC member (RM)      Germany                      IRC: jef on FreeNode                         

-- 
norBIT Gesellschaft fuer Unternehmensberatung und Informationssysteme mbH
Rheinstrasse 13, 26506 Norden
GF: Jelto Buurman, HR: Amtsgericht Emden, HRB 5502



More information about the Qgis-developer mailing list