OpenLayers + Geoserver: how to dynamically retrieve the "geometryName" of a feature layer in GeoServer

Question

I am trying to get the list of feature layers on GeoServer and then user can add layers into map at anytime they want. my question is: when using OpenLayers.Protocol.WFS loading a layer, is "geometryName" required?

since from the response of "WFSGetCapabilities" request to Geoserver, for each featureType, there are only "name, title, srsName, and featureNS". If “geometryName” is required, I have to retrive this from "DescribeFeatureType" request by enumerating the feature's properties . however, these two requests are asynchronous, I am not sure how to load this layer without user's interaction input.

anybody helps? appreciated!!

Answer 1

Even better you might not have to retrieve it at all, but it depends very much on the OpenLayers version.

2.10: geometryName is not required. If a value is not provided it will default to 'the_geom' which might not work for you, but that also depends on the WFS version you are using. If using geoserver as a backend I would try the default.

2.11 (currently in dev): no more required and (here's the great news) for WFS versions > 1 OL should figure it out by itself as per the documentation on the OL WFS proto:

http://dev.openlayers.org/docs/files/OpenLayers/Protocol/WFS/v1-js.html#OpenLayers.Protocol.WFS.v1.geometryName

Answer 2

I suppose you can do a nested async call. The outer one would be a DescribeFeatureType and the inner one would be the OpenLayers.Protocol.WFS call.

Something like (not tested):

var request = OpenLayers.Request.GET({
    url: 'http://myGeoserver:8080/geoserver/wfs?service=wfs&version=1.1.0&request=DescribeFeatureType',
    success: function (response) {

        var myGeometryName = parseResponseForgeometryName(response);

        var protocol = new OpenLayers.Protocol.WFS({
            version: "1.1.0",
            EndPointURL: "http://myGeoserver:8080/geoserver/wfs",
            featurePrefix: "catalog", //worspace 
            featureType: "myLayer", // Layer Name
            featureNS: "http://mydomain.com/catalog", // Edit Workspace Namespace URI
            geometryName: myGeometryName,
            srsName: myProjections.Mercator
        });

        var response = protocol.read({
            maxFeatures: 500,
            callback: function () {
                alert('complete');
            }
        });

    }
});