[Geoserver-users] WFS reference in WPS request

Bartosz_Sreba · February 2, 2012, 5:19pm

I want to make the following request (generated from WPS Request Builder ):

    <wps:Input>
      <ows:Identifier>features</ows:Identifier>
      <wps:Reference mimeType="application/wfs-collection-1.0"
xlink:href="http://**.**.**.**:8080/geoserver/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=rysy:ULICA"
method="GET"/>
    </wps:Input>

or

   <wps:Reference mimeType="text/xml; subtype=wfs-collection/1.0"
link:href="http://geoserver/wfs" method="POST">
                  <wps:Body>
                    <wfs:GetFeature service="WFS" version="1.0.0"
outputFormat="GML2">
                      <wfs:Query typeName="rysy:ULICA"/>
                    </wfs:GetFeature>
                  </wps:Body>
                </wps:Reference>

    <wps:Input>
      <ows:Identifier>buffer</ows:Identifier>
      <wps:Data>
        <wps:LiteralData>100</wps:LiteralData>
      </wps:Data>
    </wps:Input>
  </wps:DataInputs>
  <wps:ResponseForm>
    <wps:RawDataOutput mimeType="text/xml; subtype=wfs-collection/1.0">
      <ows:Identifier>result</ows:Identifier>
    </wps:RawDataOutput>
  </wps:ResponseForm>
</wps:Execute>

Unfortunately, request hangs up. WPS and WFS are on the same server. What is
wrong? Thanks for help.

Best regards,
Bartosz

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Andrea_Aime4 · February 2, 2012, 6:33pm

On Thu, Feb 2, 2012 at 6:19 PM, sbartosz <bartosz.sreba@anonymised.com> wrote:

I want to make the following request (generated from WPS Request Builder ):

<?xml version="1.0" encoding="UTF-8"?><wps:Execute version="1.0.0"
service="WPS" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.opengis.net/wps/1.0.0"
xmlns:wfs="http://www.opengis.net/wfs"
xmlns:wps="http://www.opengis.net/wps/1.0.0"
xmlns:ows="http://www.opengis.net/ows/1.1"
xmlns:gml="http://www.opengis.net/gml"
xmlns:ogc="http://www.opengis.net/ogc"
xmlns:wcs="http://www.opengis.net/wcs/1.1.1"
xmlns:xlink="http://www.w3.org/1999/xlink"
xsi:schemaLocation="http://www.opengis.net/wps/1.0.0
http://schemas.opengis.net/wps/1.0.0/wpsAll.xsd">
<ows:Identifier>gt:BufferFeatureCollection</ows:Identifier>
<wps:DataInputs>

<wps:Input>
<ows:Identifier>features</ows:Identifier>
<wps:Reference mimeType="application/wfs-collection-1.0"
xlink:href="http://**.**.**.**:8080/geoserver/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=rysy:ULICA"
method="GET"/>
</wps:Input>

or

<wps:Reference mimeType="text/xml; subtype=wfs-collection/1.0"
link:href="http://geoserver/wfs" method="POST">
<wps:Body>
<wfs:GetFeature service="WFS" version="1.0.0"
outputFormat="GML2">
<wfs:Query typeName="rysy:ULICA"/>
</wfs:GetFeature>
</wps:Body>
</wps:Reference>

<wps:Input>
<ows:Identifier>buffer</ows:Identifier>
<wps:Data>
<wps:LiteralData>100</wps:LiteralData>
</wps:Data>
</wps:Input>
</wps:DataInputs>
<wps:ResponseForm>
<wps:RawDataOutput mimeType="text/xml; subtype=wfs-collection/1.0">
<ows:Identifier>result</ows:Identifier>
</wps:RawDataOutput>
</wps:ResponseForm>
</wps:Execute>

Unfortunately, request hangs up. WPS and WFS are on the same server. What is
wrong? Thanks for help.

Not sure, it may be that the wfs schema locks prevent wfs feature
collection parsing
and generation at the same time (just a guess, could be wrong here).

If you need to pull data from inside GeoServer it's much better to use the
xlink:href="http://geoserver/wfs" url, which is a fake one GeoServer
will recognize
and will make it so that the data is fed into the process directly
from the source,
without going through parsing and encoding of the GML

Cheers
Andrea

--
-------------------------------------------------------
Ing. Andrea Aime
GeoSolutions S.A.S.
Tech lead

Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy

phone: +39 0584 962313
fax: +39 0584 962313
mob: +39 339 8844549

http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://www.youtube.com/user/GeoSolutionsIT
http://www.linkedin.com/in/andreaaime
http://twitter.com/geowolf

-------------------------------------------------------

Bartosz_Sreba · February 3, 2012, 12:35pm

Thanks for replay.

geowolf wrote

Not sure, it may be that the wfs schema locks prevent wfs feature
collection parsing
and generation at the same time (just a guess, could be wrong here).

Could you explain it more fully? Why does processing freeze? No exception is
thrown.

geowolf wrote

If you need to pull data from inside GeoServer it's much better to use the
xlink:href="http://geoserver/wfs" url, which is a fake one GeoServer
will recognize
and will make it so that the data is fed into the process directly
from the source,
without going through parsing and encoding of the GML

<wps:Reference mimeType="text/xml; subtype=wfs-collection/1.0"
xlink:href="http://geoserver/wfs" method="POST">
<wps:Body>
    <wfs:GetFeature service="WFS" version="1.0.0" outputFormat="GML2">
        <wfs:Query typeName="emuia_rysy:EMT_ULICA"/>
    </wfs:GetFeature>
</wps:Body>
</wps:Reference>

Is this ok?

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Andrea_Aime4 · February 3, 2012, 1:21pm

On Fri, Feb 3, 2012 at 1:35 PM, sbartosz <bartosz.sreba@anonymised.com> wrote:

Not sure, it may be that the wfs schema locks prevent wfs feature
collection parsing
and generation at the same time (just a guess, could be wrong here).

Could you explain it more fully? Why does processing freeze? No exception is
thrown.

The xml parsing/encoding subsystem is a complex and fragile piece of software
that has to deal with schemas that were not known about when the code is
compiled, so it has to build knowledge about them at runtime instead.
This "schema cache" is not thread safe and needs to be locked, when one
portion of GeoServer needs to update it the others have to wait.
What I imagine is going on is that the wps parsing and the wfs encoding
there are happening at the same time, generating a deadlock.
But I'm not sure, it's just a guess.

geowolf wrote

If you need to pull data from inside GeoServer it's much better to use the
xlink:href="http://geoserver/wfs" url, which is a fake one GeoServer
will recognize
and will make it so that the data is fed into the process directly
from the source,
without going through parsing and encoding of the GML

<wps:Reference mimeType="text/xml; subtype=wfs-collection/1.0"
xlink:href="http://geoserver/wfs" method="POST">
<wps:Body>
<wfs:GetFeature service="WFS" version="1.0.0" outputFormat="GML2">
<wfs:Query typeName="emuia_rysy:EMT_ULICA"/>
</wfs:GetFeature>
</wps:Body>
</wps:Reference>

Is this ok?

Yes