Invalid typenames in WFS:GetFeatures POST?

I'm trying to get even the simplest WFS HTTP_POST request to work, against a GeoServer WFS endpoint.

This HTTP_GET request works, and returns what I expect (newlines inserted for clarity):

http://mygeoserver.com/geoserver/ows?
    service=wfs&
    version=2.0.0&
    request=getfeature&
    count=3&
    typenames=mynamespace:myfeaturetype&
    cql_filter=dccode=%27XYZ%27

I'd expect this HTTP_POST request:

http://mygeoserver.com/geoserver/ows

with this request body:

<GetFeature
    version="2.0.0"
    service="WFS"
    count="3"
    xmlns="http://www.opengis.net/wfs/2.0"
    xmlns:fes="http://www.opengis.net/fes/2.0"
    xmlns:gsml="http://xmlns.geosciml.org/GeoSciML-Core/3.2"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.opengis.net/wfs/2.0
    http://schemas.opengis.net/wfs/2.0/wfs.xsd"
    >

    <Query
        typeNames="mynamespace:myfeaturetype"
        >
        <Filter  
            xmlns="http://www.opengis.net/fes/2.0" 
            xmlns:xlink="http://www.w3.org/1999/xlink" 
            xmlns:gsml="http://xmlns.geosciml.org/GeoSciML-Core/3.2" >
            <PropertyIsEqualTo>
                <ValueReference>dccode</ValueReference>
                <Literal>XYZ</Literal>
            </PropertyIsEqualTo>
        </Filter>
    </Query>
</GetFeature>

to return the same.

Instead I get an error:

    cvc-datatype-valid.1.2.3: 'mynamespace:myfeaturetype' is not a valid value of union type 'TypeNamesType'.

    cvc-attribute.3: The value 'mynamespace:myfeaturetype' of attribute 'typeNames' on element 'Query' is not valid with respect to its type, 'TypeNamesListType'.

What's throwing me for a loop is that the very same value that works for the typeNames parameter in the HTTP_GET throws an error in the HTTP_POST.

The problem seems to be that I need to specify a namespace definition in the XML for "mynamespace".

<Query
    typeNames="mynamespace:myfeaturetype"
    xmlns:mynamespace="http://????"
    >

I'm assuming that this is available, somewhere within my GeoServer installation. But where?

Solution

It will be whatever you set as the URI of the workspace mynamespace. You can look it using a describeFeature request. So for example:

curl http://localhost:8080/geoserver/wfs\?service=wfs\&version=1.1.0\&request=DescribeFeatureType\&typeName=topp:states

gives:

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:gml="http://www.opengis.net/gml" 
   xmlns:topp="http://www.openplans.org/topp" 
   xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
   elementFormDefault="qualified" 
   targetNamespace="http://www.openplans.org/topp">
  <xsd:import namespace="http://www.opengis.net/gml" schemaLocation="http://localhost:8080/geoserver/schemas/gml/3.1.1/base/gml.xsd"/>
  <xsd:complexType name="statesType">
    <xsd:complexContent>
     [....]