added fromWMSLayer convenience function to Protocol.WFS. Thanks tschaub

for the improved patch. r=tschaub (closes #1937)


git-svn-id: http://svn.openlayers.org/trunk/openlayers@8993 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Protocol/WFS.js

@@ -20,6 +20,44 @@ OpenLayers.Protocol.WFS = function(options) {
     return new cls(options);
 };
 
+/**
+ * Function: OpenLayers.Protocol.WFS.fromWMSLayer
+ * Convenience function to create a WFS protocol from a WMS layer.  This makes
+ *     the assumption that a WFS requests can be issued at the same URL as
+ *     WMS requests and that a WFS featureType exists with the same name as the
+ *     WMS layer.
+ *     
+ * This function is designed to auto-configure <url>, <featureType>,
+ *     <featurePrefix> and <srsName> for WFS <version> 1.1.0. Note that
+ *     srsName matching with the WMS layer will not work with WFS 1.0.0..
+ * 
+ * Parameters:
+ * layer - {<OpenLayers.Layer.WMS>} WMS layer that has a matching WFS
+ *     FeatureType at the same server url with the same typename.
+ * options - {Object} Default properties to be set on the protocol.
+ *
+ */
+OpenLayers.Protocol.WFS.fromWMSLayer = function(layer, options) {
+    var typeName, featurePrefix;
+    var param = layer.params["LAYERS"];
+    var parts = (param instanceof Array ? param[0] : param).split(":");
+    if(parts.length > 1) {
+        featurePrefix = parts[0];
+    }
+    typeName = parts.pop();
+    var protocolOptions = {
+        url: layer.url,
+        featureType: typeName,
+        featurePrefix: featurePrefix,
+        srsName: layer.projection && layer.projection.getCode() ||
+                 layer.map && layer.map.getProjectionObject().getCode(),
+        version: "1.1.0"
+    };
+    return new OpenLayers.Protocol.WFS(OpenLayers.Util.applyDefaults(
+        options, protocolOptions
+    ));
+};
+
 /**
  * Constant: OpenLayers.Protocol.WFS.DEFAULTS
  */

tests/Protocol/WFS.html

@@ -187,6 +187,30 @@
         t.eq(aborted, true, "abort called on response.priv");
 
     }
+    
+    function test_fromWMSLayer(t) {
+        t.plan(8);
+        var map = new OpenLayers.Map("map", {
+            projection: "EPSG:1234"
+        });
+        var layer = new OpenLayers.Layer.WMS("foo", "htttp://foo/ows",
+            {layers: "topp:states"}
+        );
+        map.addLayer(layer);
+        var protocol = OpenLayers.Protocol.WFS.fromWMSLayer(layer);
+        t.eq(protocol.url, "htttp://foo/ows", "url taken from wms layer");
+        t.eq(protocol.featurePrefix, "topp", "feature prefix correctly extracted");
+        t.eq(protocol.featureType, "states", "typeName correctly extracted");
+        t.eq(protocol.srsName, "EPSG:1234", "srsName set correctly");
+        t.eq(protocol.version, "1.1.0", "version set correctly");
+        
+        layer.params["LAYERS"] = ["topp:street_centerline", "topp:states"];
+        layer.projection = new OpenLayers.Projection("EPSG:900913");
+        protocol = OpenLayers.Protocol.WFS.fromWMSLayer(layer);
+        t.eq(protocol.featurePrefix, "topp", "featurePrefix from layer param array");
+        t.eq(protocol.featureType, "street_centerline", "first layer from layer param array as featureType"); 
+        t.eq(protocol.srsName, "EPSG:900913", "projection from layer preferred"); 
+    }
 
     function readXML(id) {
         var xml = document.getElementById(id).firstChild.nodeValue;