[thredds] XML question for WCS THREDDS catalogs
Nathan Potter
ndp at opendap.org
Wed Oct 24 10:50:53 MDT 2007
Ethan and John,
We are having a problem with (what we think is) a (valid) THREDDS
catalog entry causing the THREDDS code to throw a null pointer
exception in. (See the included emails for the background.)
The catalog entry is:
<dataset name="CCEXTTAU-INTEX.Organic+Black.Carbon.Aerosol"
urlPath="wcs/DataFed/NetCDF/CCEXTTAU-INTEX.Organic
+Black.Carbon.Aerosol"
ID="wcs/DataFed/NetCDF/CCEXTTAU-INTEX.Organic
+Black.Carbon.Aerosol" >
<property name="wcs-request" value="http://
webapps.datafed.net/ogc_NASA.wsfl?
SERVICE=WCS&REQUEST=GetCoverage&VERSION=1.0.0&CRS=EPSG:
4326&COVERAGE=GOCART_G_OL.CCEXTTAU&TIME=2007-06-24T23:00:00&
BBOX=-180,-90,180,90,0,0&WIDTH=-1&HEIGHT=-1&DEPTH=-1&FOR
MAT=NetCDF" />
<property name="returnType" value="netCDF" />
<property name="cacheTime" value="600" />
<serviceName>OPeNDAP-Hyrax</serviceName>
</dataset>
The stack trace that I get is:
java.lang.NullPointerException
at thredds.servlet.CatalogServicesServlet.handleCatalogServiceRequest
(CatalogServicesServlet.java:226)
at thredds.servlet.DataRootHandler.processReqForCatalog
(DataRootHandler.java:1117)
at opendap.bes.ThreddsDispatchHandler.handleRequest
(ThreddsDispatchHandler.java:232)
at opendap.coreServlet.DispatchServlet.doGet(DispatchServlet.java:437)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
And it appears to a problem ONLY when there is a plus sign ("+") in
the value of the ID attribute.
Any ideas?
N
Begin forwarded message:
> From: Daniel Holloway <d.holloway at opendap.org>
> Date: October 23, 2007 11:01:37 AM PDT
> To: Nathan Potter <ndp at opendap.org>
> Subject: Re: XML question for WCS THREDDS catalogs
>
>
> On Oct 23, 2007, at 1:53 PM, Nathan Potter wrote:
>
>>
>> On Oct 23, 2007, at 10:01 AM, Daniel Holloway wrote:
>>
>>>
>>> On Oct 23, 2007, at 12:21 PM, Nathan Potter wrote:
>>>
>>>>
>>>> Dan,
>>>>
>>>> Several things strike me as potential problems:
>>>>
>>>> 1) The Exception is being thrown deep in the THREDDS code.
>>>> Disturbingly, it appears to be in a servlert implmentation that
>>>> I am not running in Hyrax. Are you running a TDS too?
>>>
>>> Hi Nathan,
>>>
>>> Thanks for the quick reply. No, I'm not running a TDS on
>>> this platform as well.
>>>
>>>>
>>>> 2) A plus sign in a URL (outside of the constraint expression)
>>>> mught get filtered by the new security features in the PLFS, and
>>>> this would cause trouble!
>>>>
>>> It's not a big problem for me, I was more interested in
>>> knowing where the problem existed and why. If these characters
>>> aren't allowable in XML, or THREDDS, then I need to document that
>>> in the configuration guide for the handler. It seems to me that
>>> these are valid characters, or at least should be able to be
>>> replaced with '&plus' without it causing these problems.
>>>
>>> Anyway, welcome back and thanks for the reply.
>>>
>>> Dan
>>>
>>>
>>> p.s. Should we enter a ticket on this to keep track of the
>>> problem?
>>
>>
>> I think so. I am still pretty non functional from jet lag.... I'll
>> be on my game tomorrow and I'll try to tack it down. Will you send
>> me the THREDDS catalog entry that caused the error?
>>
>
> Nathan,
>
> Here's the dataset element that is causing the problem. The
> best bet is to replace the element in your example catalog.xml with
> this one. The problem seems to be the '+' sign in the ID
> attribute. I've experimented and found that it only fails when the
> '+' sign is in the ID attribute, no idea why.
>
> --------
> <dataset name="CCEXTTAU-INTEX.Organic
> +Black.Carbon.Aerosol"
> urlPath="wcs/DataFed/NetCDF/CCEXTTAU-
> INTEX.Organic+Black.Carbon.Aerosol"
> ID="wcs/DataFed/NetCDF/CCEXTTAU-INTEX.Organic
> +Black.Carbon.Aerosol" >
> <property name="wcs-request" value="http://
> webapps.datafed.net/ogc_NASA.wsfl?
> SERVICE=WCS&REQUEST=GetCoverage&VERSION=1.0.0&CRS=EPSG:
> 4326&COVERAGE=GOCART_G_OL.CCEXTTAU&TIME=2007-06-24T23:00:00&am
> p;BBOX=-180,-90,\
> 180,90,0,0&WIDTH=-1&HEIGHT=-1&DEPTH=-1&FORMAT=NetCDF"
> />
> <property name="returnType" value="netCDF" />
> <property name="cacheTime" value="600" />
> <serviceName>OPeNDAP-Hyrax</serviceName>
> </dataset>
>
> -------
>
> Dan
>
>> N
>>
>>
>>
>>>
>>>> N
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Oct 23, 2007, at 8:52 AM, Daniel Holloway wrote:
>>>>
>>>>> Nathan,
>>>>>
>>>>> I've been playing with the configuration of a Hyrax server
>>>>> using the latest OLFS/BES code. There is/was a dataset that
>>>>> has a '+' sign in the name. I get an error from the OLFS when
>>>>> using this string in the ID attribute of the dataset element.
>>>>> As follows:
>>>>> ------
>>>>> <dataset name="CCEXTTAU-INTEX.Organic
>>>>> +Black.Carbon.Aerosol"
>>>>> urlPath="wcs/DataFed/NetCDF/CCEXTTAU-
>>>>> INTEX.Organic+Black.Carbon.Aerosol"
>>>>> ID="wcs/DataFed/NetCDF/CCEXTTAU-
>>>>> INTEX.Organic+Black.Carbon.Aerosol" >
>>>>> <property name="wcs-request" value="http://
>>>>> webapps.datafed.net/ogc_NASA.wsfl?
>>>>> SERVICE=WCS&REQUEST=GetCoverage&VERSION=1.0.0&CRS=EPSG
>>>>> :
>>>>> 4326&COVERAGE=GOCART_G_OL.CCEXTTAU&TIME=2007-06-24T23:00:0
>>>>> 0&BBOX=-180,-90,\
>>>>> 180,90,0,0&WIDTH=-1&HEIGHT=-1&DEPTH=-1&FORMAT=NetC
>>>>> DF" />
>>>>> <property name="returnType" value="netCDF" />
>>>>> <property name="cacheTime" value="600" />
>>>>> <serviceName>OPeNDAP-Hyrax</serviceName>
>>>>> </dataset>
>>>>> -------
>>>>>
>>>>> The error is:
>>>>> -------
>>>>> Error { code = -1; message = "java.lang.NullPointerException:
>>>>> null [CatalogServicesServlet.java - line 226]"; };
>>>>> -------
>>>>>
>>>>> I only get an error if the '+' sign is used in the 'ID'
>>>>> attribute, the others don't seem to make any difference. I've
>>>>> tried replacing the '+' with a + but that breaks the
>>>>> server's access to the catalog completely. Not exactly sure
>>>>> why but if I use a + in the XML I get a 'Resource Not
>>>>> Found' response from the server when trying to open the catalog.
>>>>>
>>>>> Anyway, figured I'd ask before submitting a Trac ticket.
>>>>>
>>>>> Dan
>>>>>
>>>>
>>>> = = =
>>>> Nathan Potter ndp at opendap.org
>>>> OPeNDAP, Inc. 541.752.1852
>>>>
>>>
>>
>> = = =
>> Nathan Potter ndp at opendap.org
>> OPeNDAP, Inc. 541.752.1852
>>
>
= = =
Nathan Potter ndp at opendap.org
OPeNDAP, Inc. 541.752.1852
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