How to convert WFS request to GML

Question

I have the following:

 var popProto = new OpenLayers.Protocol.WFS({
    url:  WFS_HOST,
    version: "1.1.0",
    featureType: layerName,
    featureNS: namespace,
    srsName: "EPSG:4326",
    propertyNames: ["grid_code"],
    defaultFilter: popFilter
});

which I wish to convert to GML so that I can chain it to a WPS request. I've been looking around for sometime, but I can't get a way out. Any suggestions on how I can convert this to GML format will be appreciated very much.

UPDATE: Below is my attempt so far:

function createWPSExecuteRequest(namespace, layerName, popFilter) {
    var request = OpenLayers.Format.XML.prototype.write(new OpenLayers.Format.WPSExecute().writeNode('wps:Execute', {
        identifier: 'gs:Aggregate',
        dataInputs: [{
            identifier: 'features',
            reference: {
                mimeType: 'text/xml',
                href: WFS_HOST,
                method: 'POST',
                body: {
                    wfs: {
                        featureType: layerName,
                        version: '1.1.0',
                        featureNS: namespace,
                        srsName: "EPSG:4326",
                        propertyNames: ["grid_code"],
                        defaultFilter: popFilter
                    }
                }
            }, 
            identifier: 'aggregationAttribute',
            data: {literalData: 'grid_code'}
            .....more inputs here....
        }],
        responseForm: {
            rawDataOutput: {
                identifier: 'result'
            }
        }
    }));

    return request;
}

But the identifier: 'aggregationAttribute' and defaultFilter: popFilter is not being included in the generated GML. Anything I may be doing wrong?

Answer 1

If you look at the response in firebug you will see that WFS responds all the features in GML format.

If you just want the GML and not the openlayers features call the WFS (WFS_HOST) rest service directly. much of the response is in GML.