[GeoNode-users] GeoNode - PyCSW integration issues

Thu Jul 27 04:39:26 PDT 2017

Hi Alessio: thanks for the info.  Comments interleaved:

On Wed, 26 Jul 2017, Alessio Fabiani wrote:

> Date: Wed, 26 Jul 2017 11:10:36 +0200
> From: Alessio Fabiani <alessio.fabiani at geo-solutions.it>
> To: geonode-devel <geonode-devel at lists.osgeo.org>,
>     geonode-users <geonode-users at lists.osgeo.org>
> Subject: [GeoNode-users] GeoNode - PyCSW integration issues
> 
> Dear all,
> I want to highlight some important issues about the current integration
> between GeoNode and PyCSW.
>
> Other than a non-trivial security issue (basically the CSW exposes metadata
> for all Layers no matter if they are accessible or not by the user),

This is in my queue to fix (half way there).

> one
> more, I would say, big issue is that currently is not possible to recognize
> the Layer "real name" from the metadata documents.
>
> Let me provide an example. Here below a snippet of a DublinCore XML
> produced by PyCSW
>
> ...
> <csw:Record>
>    <dc:identifier>941a8d7e-7159-11e7-b283-002215079c40</dc:identifier>
>    <dc:title>san_andres_y_providencia_highway</dc:title>
>    <dc:type>dataset</dc:type>
>    <dc:subject/>
>    ...
>    <dct:references scheme="WWW:DOWNLOAD-1.0-http--download">
> http://localhost:8080/geoserver/wms?request=GetLegendGraphic&format=image/png&WIDTH=20&HEIGHT=20&LAYER=geonode:san_andres_y_providencia_highway&legend_options=fontAntiAliasing:true;fontSize:12;forceLabels:on
> </dct:references>
>    <dct:references scheme="OGC:WMS">
> http://localhost:8080/geoserver/geonode/wms</dct:references>
>    <dct:references scheme="OGC:WFS">
> http://localhost:8080/geoserver/geonode/wfs</dct:references>
> ...
>
> (full XML here https://pastebin.com/Wu0vm79B)
>
> Seems to be good right? *Wrong!* There some important things missing here:
>
> 1. It is not possible to recognize the layer name at all; The element
> "title" is mapped to the resource title, meaning that whenever I change it
> on the metadata into a human readable fashion, I lose the layer name forever
>

You should use ISO instead?  See below comment.

> 2. Layer qualified name is missing; if the name had a namespace, like on
> GeoServer, it is not possible to know which is at all
>
> 3. WMS and WFS links cannot be used at all, since the layer name cannot be
> retrieved anywhere
>

Anyone who wants to do tight coupling to OWS resources via CSW search
workflows needs to use the ISO output, which provides the bare URL
as well as the given Layer/FeatureType/Coverage.

Otherwise, the Dublin Core approach allows for discovery followed by
the client doing a full round trip (GetCapabilities, etc.) to be able
to find the layer again.  This is not optimal, which is exactly why
the CSW ISO Application Profile was created to help tight couplling
workflows.

If there are issues in the ISO output then let's tackle those?

> *Proposal*
>
> Following the notes written by Stephen Richard here
> https://github.com/geopython/pycsw/wiki/Geonode-notes
>
> the proposal here would be to add more references
>
> OGC:WMS-1.1.1-http-get-capabilities
> OGC:WMS-1.3.0-http-get-capabilities
> OGC:WMS-1.1.1-http-get-map
> OGC:WMS-1.3.0-http-get-map
> OGC:WMS-1.1.1-http-get-featureinfo
> OGC:WMS-1.3.0-http-get-featureinfo
>
> OGC:WFS-1.0.0-http-get-capabilities
> OGC:WFS-1.0.0-http-describe-feature
> OGC:WFS-1.0.0-http-get-feature
>
> OGC:WCS-1.1.0-http-get-capabilities
> OGC:WCS-1.1.0-http-describe-coverage
> OGC:WCS-1.1.0-http-get-coverage
> ...

Note that we promoted this into a canonical lookup at:

https://github.com/OSGeo/Cat-Interop/blob/master/LinkPropertyLookupTable.csv

>
> in order to let CSW being able to send correct links to the clients.
>
> If there are no objections, I will create a PR accordingly related to the
> following ISSUE
>
> https://github.com/GeoNode/geonode/issues/2720#issuecomment-262829872
>
> Please comment on this.
>
>
> Regards,
>
> Alessio Fabiani
>
> ==
> GeoServer Professional Services from the experts! Visit http://goo.gl/it488V
> for more information.
> ==
>
> Ing. Alessio Fabiani
>
> @alfa7691
> Founder/Technical Lead
>
>
> GeoSolutions S.A.S.
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