8.2. Request Parameters

WPS requests must typically be encoded as XML; however, the GeoServer documentation is not always clear about exactly what XML is required. This page explains a few different parameter types, with examples of how to represent them.

8.2.1. Selecting Layers

The primary input of a process is usually a feature collection, representing a layer in GeoServer. A layer can be selected as:

<wps:Input>
   <!-- name of the input parameter from the process definition -->
  <ows:Identifier>features</ows:Identifier>
  <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" xmlns:cabs="cabs">
        <!-- typeName is workspace:layer -->
        <wfs:Query typeName="cabs:Cabs_features"/>
      </wfs:GetFeature>
    </wps:Body>
  </wps:Reference>
</wps:Input>

8.2.2. CQL Filters

CQL filters can be represented as complex XML elements, but it’s often easier to represent them as text strings:

<wps:Input>
  <!-- name of the input parameter from the process definition -->
  <ows:Identifier>filter</ows:Identifier>
  <wps:Data>
    <wps:ComplexData mimeType="text/plain; subtype=cql">
      <!-- filter string, wrapped in a CDATA field to allow special characters like &lt; and &gt; -->
      <![CDATA[INCLUDE]]>
    </wps:ComplexData>
  </wps:Data>
</wps:Input>

In the GeoServer interactive WPS request builder, select TEXT and choose "text/plain; subtype=cql", then enter the query text in the text box.

8.2.3. Other Inputs

Most other inputs (string, integers, Booleans, etc) can be represented as literal data:

<wps:Input>
  <!-- name of the input parameter from the process definition -->
  <ows:Identifier>histogram</ows:Identifier>
  <wps:Data>
    <wps:LiteralData>true</wps:LiteralData>
  </wps:Data>
</wps:Input>

8.2.4. Output Formats

Responses can be rendered in any output format supported by GeoServer; common ones are GeoJSON and GML:

<!-- GeoJSON -->
<wps:ResponseForm>
   <wps:RawDataOutput mimeType="application/json">
      <ows:Identifier>result</ows:Identifier>
   </wps:RawDataOutput>
</wps:ResponseForm>

<!-- GML -->
<wps:ResponseForm>
  <wps:RawDataOutput mimeType="text-xml; subtype=wfs-collection/1.0">
    <ows:Identifier>result</ows:Identifier>
  </wps:RawDataOutput>
</wps:ResponseForm>

In the GeoServer interactive WPS request builder, select VECTOR_LAYER, then choose the layer.