Check if WMS layer is queryable in OpenLayers?

Question

I'm running a map with lots of different WMS layers published by GeoServer. Some of them are queryable, some of them are not. How can I tell that with OpenLayers API?

I'm requesting GetFeatureInfo and I need to request only the queryable layers, layers with queryable param set to false always return "Layer is not queryable" when requested - and that's what I want to hide from users. I looked into OpenLayers.Map.layers and found no "queryable" property.

UPDATE (to the first comment): This works fine as long as I use it with localhost:8080/geoserver/wms?service=WMS&version=1.1.1&request=GetCapabilities&. When I tried to get capabilities from http://www.edpp.cz:8080/geoserver/wms?service=WMS&version=1.1.1&request=GetCapabilities&, I got empty array of layers as a result.

I'm trying it with the following code:

function getCapabilities(offline) {
 var url = '';
 if (offline) {
 url = 'localhost:8080/geoserver/wms?service=WMS&version=1.1.1&request=GetCapabilities&';
 }
 else {
 url = 'http://www.edpp.cz:8080/geoserver/wms?service=WMS&version=1.1.1&request=GetCapabilities&'
 }
 var layers = []
 ,result
 ,request = OpenLayers.Request.GET({
 url: url
 ,success: function(response) {
 var format = new OpenLayers.Format.XML()
 ,xml = format.read(response.responseText)
 ,text = format.write(xml)
 ,CAPformat = new OpenLayers.Format.WMSCapabilities()
 ,cap = CAPformat.read(xml);
 if (cap.capability) {
 for (var len = cap.capability.layers.length-1; len >= 0; len -= 1) {
 if (cap.capability.layers[len].queryable) {
 layers.push(cap.capability.layers[len].name);
 }
 }
 }
 }
 });
 return layers; //ARRAY
}

Answer 1

The queriable information is contained in the WMS capabilities document, the one that gets returned when you hit http://host:port/geoserver/ows?request=GetCapabilities&service=WMS

OpenLayers has this class to parse it: http://dev.openlayers.org/docs/files/OpenLayers/Format/WMSCapabilities-js.html

• Michal Zimmermann: Hi, this works fine as long as I use it with localhost:8080/geoserver/…. When I tried to get capabilities from edpp.cz:8080/geoserver/…, i got empty array of layers as a result.
• Tommaso: You need a proxy to perform ajax calls outside the domain of your page Same origin policy - wikipedia.