[ckan-dev] CKAN CSW Server support: 'outputSchema' issues

Tue Nov 13 11:38:46 UTC 2012

CKAN's current CSW implementation is really basic and unstable, and
should be not be considered ready for production.

We are commited to integrate pycsw to provide a proper full CSW
interface, and this is something that will happen at some point in the
next months (Tom and Angelos have already provided very valuable
feedback on this). You can try and fix this issues on the current csw
controller [1], but I'd recommend wait for the pycsw integration, as
we will not be supporting the current implementation.

Adrià

[1] https://github.com/okfn/ckanext-spatial/blob/master/ckanext/spatial/controllers/csw.py

On 13 November 2012 09:27, David Read <david.read at hackneyworkshop.com> wrote:
> Ryan,
>
> My suggestion to try OWSLib was with the third-party servers you are
> harvesting on.
>
> As the documentation says, the CWS server that CKAN provides itself is
> very basic and doesn't cope with many variants of CSW. In recent tests
> I found that such simple things fox it, such as putting parameter
> names in capital letters and some parameters are defaulted on a POSTs
> but not on a GET. My understanding is that it was designed only for a
> Geonetworks server to harvest from it, since that was what the paying
> client asked for.
>
> I don't think it would take too much work to get it to work a lot
> smoother, and that would be great if you were able to contribute this.
>
> Tom Kralidis has been talking for a while about integrating PyCSW code
> in. That is a reasonably large task since the CKAN model would have to
> have a good mapping of the ISO fields. To get it started though, it
> might be worth copying the PyCSW server code and getting it to server
> CKAN's HarvestedObjects which contain the ISO XML.
>
> So, I'm afraid it's not all on a plate for you ready to go to do what
> you want... but it's a good start. I guess this is a relatively small
> area of open source and the more people that contribute, the stronger
> it will be for the next organisation.
>
> David
>
> On 12 November 2012 23:43, Ryan Hodges <rhodges at ecotrust.org> wrote:
>> Hi all,
>>
>>
>>
>> I have been attempting to run some basic CSW requests against a test install
>> of CKAN 1.8 that we’ve been testing CSW harvesting with (Ckanext-harvest +
>> Ckanext-spatial, all installed from source).
>>
>>
>>
>> It was recommended in a prior thread that I test out the version of OWSLIB,
>> which in the past was a OKFN specific fork but is now pointed here:
>> https://github.com/geopython/OWSLib
>>
>>
>>
>> Running with this (v0.5.1), I ran the usage examples in the README, except
>> with CSW instead of WMS on my own install:
>>
>>
>>
>>>>> from owslib.csw import CatalogueServiceWeb
>>
>>>>> csw = CatalogueServiceWeb(‘http://ckan.labs.ecotrust.org/csw’,
>>>>> version=’2.0.2’)
>>
>>>>> csw.getrecords()
>>
>>>>> csw.response
>>
>>
>>
>> Normally that last command would give XML of the records retrieved, but in
>> this case you get this error:
>>
>> ------------------------------------------------------------------------
>>
>> <ows:ExceptionReport xmlns:dc="http://purl.org/dc/elements/1.1/"
>> xmlns:rim="urn:oasis:names:tc:ebxml-regrep:xsd:rim:3.0"
>> xmlns:xs="http://www.w3.org/2001/XMLSchema"
>> xmlns:dct="http://purl.org/dc/terms/" xmlns:ows="http://www.opengis.net/ows"
>> xmlns:xs2="http://www.w3.org/XML/Schema"
>> xmlns:gml="http://www.opengis.net/gml"
>> xmlns:dif="http://gcmd.gsfc.nasa.gov/Aboutus/xml/dif/"
>> xmlns:xlink="http://www.w3.org/1999/xlink"
>> xmlns:gco="http://www.isotc211.org/2005/gco"
>> xmlns:gmd="http://www.isotc211.org/2005/gmd"
>> xmlns:ogc="http://www.opengis.net/ogc"
>> xmlns:fgdc="http://www.opengis.net/cat/csw/csdgm"
>> xmlns:csw="http://www.opengis.net/cat/csw/2.0.2"
>> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>> xsi:schemaLocation="http://schemas.opengis.net/ows/1.0.0/owsExceptionReport.xsd"
>> version="1.0.0">
>>
>>     <ows:Exception locator="outputSchema"
>> exceptionCode="InvalidParameterValue">
>>
>>
>> <ows:ExceptionText>http://www.opengis.net/cat/csw/2.0.2</ows:ExceptionText>
>>
>>     </ows:Exception>
>>
>> </ows:ExceptionReport>
>>
>> ------------------------------------------------------------------------
>>
>>
>>
>> I suspected my install, but it sounds like it’s a CKAN issue. From the IRC
>> discussion:
>>
>>
>>
>> tomkralidis –
>>
>> CKAN is not serving CSW properly. The CSW server is having issues with the
>> outputschema. When I pass outputschema='http://www.isotc211.org/2005/gmd' in
>> getrecords(), then I get a 500.
>>
>> tomkralidis –
>>
>> the default getrecords() passes typenames='csw:Record', which the CKAN CSW
>> currently doesn't support. But it doesn't fail on that (but it should). It
>> fails on outputschema. When you try to pass the correct outputschema, the
>> 500 above happens
>>
>>
>>
>> Is there a ticket for this, or something on my end I need to fix?
>>
>>
>>
>> Thanks,
>>
>> Ryan Hodges | Applications Developer | Ecotrust
>>
>> 721 NW 9th Avenue, Suite 200 • Portland, OR 97209
>>
>> T (503) 467.0800 | F (503) 222.1517 | www.ecotrust.org
>>
>>
>>
>>
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