[ckan-dev] CSW gather stage: get only datasets changed since X

Tue Nov 14 12:16:36 UTC 2017

On Tue, 14 Nov 2017, Knud Möller wrote:

> Date: Tue, 14 Nov 2017 02:34:21 -0800
> From: Knud Möller <knud at datalysator.com>
> Reply-To: CKAN Development Discussions <ckan-dev at lists.okfn.org>
> To: CKAN Development Discussions <ckan-dev at lists.okfn.org>
> Subject: [ckan-dev] CSW gather stage: get only datasets changed since X
> 
> Hi all,
>
> I’m trying to restrict the number of datasets I receive in the gather stage
> of a CSW harvester (based on CSWHarvester from ckanext-spatial) to only
> include those that changed since a date X.
>
> I managed to write a manual query using an ogc:Filter that does that. I’ve
> tried it with curl and via OWSLib. However, CswService does not expose the
> ‘constraints’ parameter from OWSLib’s getrecords2() that allows to use
> ogc:Filters, only a parameter for cql-based filters.
>
> So, my question is: what would the query for "datasets changed since X”
> look like in CQL? Alternatively, would it make sense to add a “constraints”
> parameter to CswService, so that we can use ogc:Filters? That shouldn’t be
> hard; I’d be happy to create a PR for that.

+1 to supporting proper OGC filters, given not all CSW servers support CQL.

..Tom

>
> Cheers,
> Knud