Re: [thredds] TDS Catalog Validation Service

• To: Nathan Potter <ndp@xxxxxxxxxxx>
• Subject: Re: [thredds] TDS Catalog Validation Service
• From: Nathan Potter <ndp@xxxxxxxxxxx>
• Date: Tue, 30 Dec 2008 12:55:46 -0800

I have a third question:



3 ---------------

    thredds:service/@base + thredds:datasetScan/@path + "/catalog.xml"


Example: On localhost:8080 we find this catalog:


    <service name="tds" serviceType="OPeNDAP" base="/ncDODS/"/>

        <filter>
            <exclude wildcard=".*" atomic="true" collection="true"/>
            <include wildcard="*"/>
        </filter>
        <addDatasetSize />
    </datasetScan>

So the catalog access URL would be:

    http://localhost:8080/ncDODS/data/catalog.xml

???

N






On Dec 30, 2008, at 10:42 AM, Nathan Potter wrote:

John,

Point me at the crawler code, I'll look and see how it works with thredds:catalogRef elements.

I guess I really have two questions:


1 ------------------

I am looking at the xlink:href attribute of the thredds:catalogRef elements.

Would it be far to say that this example:

<catalogRef xlink:href="CEOP/catalog.xml" xlink:title="CEOP" name="CEOP/"/>

References a file relative to the parent catalogs position in the catalog structure?

Example 1:

So if the catalog containing this thredds:catalogRef was accessed using this URL:

   http://localhost:8080/thredds/data/catalog.xml

Then the above catalogRef should lead you here:

   http://localhost:8080/thredds/data/CEOP/catalog.xml


Example 2:
And on the same server, this example:

<catalogRef xlink:href="/toplevel/path/catalog.xml" xlink:title="catalog" name="catalog"/>

Would lead here:

   http://localhost:8080/toplevel/path/catalog.xml

No matter which catalog this thredds:cataogRef appeared.


Example 3:
And this example:

<catalogRef xlink:href="http://motherlode.ucar.edu:8080/thredds/idd/satellite.xml " xlink:title="Motherlode" name="Motherlode"/>

Would lead here:

   http://motherlode.ucar.edu:8080/thredds/idd/satellite.xml

No matter which catalog this thredds:cataogRef appeared.

Is that the way you see it working?





2 ------------------

Is there a place that describes how data access URL's are too be built from thredds:dataset elements ?

My understanding is that it's like this:

 thredds:service/@base + thredds:dataset/@urlPath

Is that a correct interpretation of the catalog semantics? So if we're on localhost:8080, and the service/@base is "/opendap/" then this catalog snippet:

<service name="hyrax" serviceType="OPeNDAP" base="/opendap/"/>

<dataset name="Datset with a compound service and multiply inherited services." ID="bears" urlPath="bears.nc">

  <serviceName>hyrax</serviceName>
</dataset>

Would produce this base data access URL: http://localhost:8080/opendap/bears.nc and additional service related stuff would get added to that.

Is that right?


Thanks,

Nathan




On Dec 30, 2008, at 9:16 AM, John Caron wrote:

Hi Nathan:

We dont have ready-made code that validates catalogs and follows the catalog refs. However, we do have some generic catalog crawler code, where you get callbacks to your own code to do whatever you want. let me know if thats helpful...

Nathan Potter wrote:

Greetings,

I have a question about validating the semantics of a THREDDS catalog. The attached catalog contains a number of thredds:catalogRef elements. The urlPath attribute for these should be able to be used to resolve the individual catalogs. Is there a validation for that similar to using the built in Catalog Validation service that come rolled in the TDS? I tested the attached catalog against the service at motherload.ucar.edu: http://motherlode.ucar.edu:8080/thredds/catalogServices?cmd=validate&catalog=http://ndp.opendap.org:8080/opendap/data/catalog.xml And it passed, but I don't imagine it attempted to check down the catalog hierarchy.

Any ideas?
Thanks,
Nathan
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= = =
Nathan Potter                        ndp at opendap.org
OPeNDAP, Inc.                        541.752.1852
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Nathan Potter                        ndp at opendap.org
OPeNDAP, Inc.                        541.752.1852

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Nathan Potter                        ndp at opendap.org
OPeNDAP, Inc.                        541.752.1852

• Follow-Ups:
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    • From: Nathan Potter
  • Re: [thredds] TDS Catalog Validation Service
    • From: John Caron
  • Re: [thredds] TDS Catalog Validation Service
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