[OWSLib-devel] nextRecord missing

[Tom Kralidis]

On Tue, 22 Oct 2013, David Read wrote:

> Date: Tue, 22 Oct 2013 12:33:37 +0100
> From: David Read <david.read at hackneyworkshop.com>
> To: owslib-devel at lists.osgeo.org
> Subject: [OWSLib-devel] nextRecord missing
> 
> Have any of you encountered a CSW Server that doesn't give a
> nextRecord value when doing a GetRecords request? I'm using OWSLib to
> talk to it and it gives an exception and I have a patch I can push
> that'll avoid the exception. But is that what we want it to do?
>
> The server is running "Conterra sdi.suite". Apparently Conterra's view
> is that it is best practice for the client to keep track of where it
> is up to, and not to rely on the server, and so they adhere to the XSD
> schema rather than the guidance on this particular issue.
>
> The schema http://schemas.opengis.net/csw/2.0.2/CSW-discovery.xsd says
> it is OPTIONAL:
>
> <xsd:attribute name="nextRecord" type="xsd:nonNegativeInteger" use="optional"/>
>
> yet the spec it claims to reflect says it is REQUIRED:
>
> http://portal.opengeospatial.org/files/?artifact_id=21460
>
> <xsd:attribute name="nextRecord"
>                     type="xsd:nonNegativeInteger"
>                              use="required"/>
>
> Is the XSD (and therefore Conterra) simply wrong? Or is this justifiable?
>

Unfortunately, D.1.1 of the spec says:

"In the event of a discrepancy between the bundled and online versions of the
XML Schema files, the online files shall be considered authoritative."

Though it would be really nice (and really easy) for the CSW server impl to support nextRecord.

This will also trip up existing OWSLib clients who may be doing something with
nextRecord already assuming it's an int?

David: sure, submit a PR against master? It would be really really great also
if you could provide a small test case in our doctests.

example: https://github.com/geopython/OWSLib/blob/master/tests/doctests/csw_nlr.txt

> BTW here's my patched version of OWSLib running:
>
>    >>> from owslib.csw import CatalogueServiceWeb as cs
>    >>> c=cs('https://gateway.ceh.ac.uk/soapServices/CSWStartup')
>    >>> c.version
>    '2.0.2'
>    >>> c.getrecords2()
>    >>> c.results
>    {'matches': 291, 'nextrecord': None, 'returned': 10}
>

So nextrecord: None would mean that the element did not exist, correct?

> David