Even Rouault kirjoitti 24.10.2017 klo 20:23:
On mardi 24 octobre 2017 17:07:51 CEST Ari Jolma wrote:
> Whoa! How hard can XML be? I have a real Capabilities document (from
> well known company) which defines *both* default and ows namespace to
> http://www.opengis.net/ows/2.0.
>
> Thus, to be sure, I need to look for *both* ows:ServiceIdentification
> and ServiceIdentification. Or maybe loop through all elements and check
> for both at each element?
If there's no ambiguity with elements having same names in different
namespaces, you can just strip namespace prefixes from elements with
CPLStripXMLNamespace(psRoot, NULL, true)
I implemented a solution, where the namespace prefixes is a list
(CPLStringList). That is probably a general solution and actually quite
simple.
Some fundamental thoughts on how to use the driver. The idea is to allow
starting from a GetCapabilities request. The initial dataset name is thus
WCS:URL
where the URL may be without any parameters. We'll add service and
request parameters but *not* version or acceptVersions since the server
should return the latest supported version. The one I test with seems to
return 1.1.2 and 2.0.1 only when requested. We'll leave it to user to
add the version/acceptVersions. The user can also add updateSequence and
other parameters. If the user adds coverage/identifiers/coverageId then
we'll proceed directly to DescribeCoverage or further to GetCoverage if
there are bounding boxes or such. DescribeCoverage is needed unless it
is cached (see below) since it probably contains important metadata
(nodata value, min and max values etc).
Errors are reported to the user - it is important to know whether the
error is HTTP 404 or ExceptionReport InvalidParameterValue.
The driver currently honors some HTTP parameters such as timeout length,
authorization etc. and they are in the service XML. How to forward them
to the driver in the case of this simple dataset name case? Environment
variables or somehow coded into the dataset name? (for example
"WCS:x=y,URL=url" ?)
Also, it would be useful to cache at least the capabilities and coverage
description. I have not yet thought much about that but using something
like $HOME/.gdal/wcs_cache would be preferred I guess? Then there is the
question how the user can control refreshing the cache - with options as
above?
Ari
--
Spatialys - Geospatial professional services
http://www.spatialys.com
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