Its possible to catch ServiceException in Openlayers?

Question

Im trying to catch exception in OpenLayers using vector layers in conjunction with http protocol, its possible to intercept an ServiceException from geoserver ... it will be great to display some kinda of error message when it happens.

here my snippet:

var layer = new OpenLayers.Layer.Vector("Foo", {
  projection: new OpenLayers.Projection("EPSG:4326"),
  strategies: [new OpenLayers.Strategy.Fixed()],
  reportError: true,
  protocol: new OpenLayers.Protocol.HTTP({
    url: "/geoserver/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=ns:foo&outputFormat=json&viewparams=foo:var;",
    format: new OpenLayers.Format.GeoJSON()
  })
});

ideas ??

thks !

Answer 1

Try using the callback and see what it returns:

var layer = new OpenLayers.Layer.Vector("Foo", {
  projection: new OpenLayers.Projection("EPSG:4326"),
  strategies: [new OpenLayers.Strategy.Fixed()],
  reportError: true,
  protocol: new OpenLayers.Protocol.HTTP({
    url: "/geoserver/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=ns:foo&outputFormat=json&viewparams=foo:var;",
    format: new OpenLayers.Format.GeoJSON()
    callback: function(e) { 
       alert('Did at least something happen?'); 
       console.log(e);
    }
  })
});

Answer 2

the issue comes from "OpenLayers.Strategy.Fixed" this strategy overrides callback method, soo ... i create a fork from openlayers and implements event listeners for strategies ... take a look:

var fixed = new OpenLayers.Strategy.Fixed();

fixed.events.register("fail", this, function (response) {
  console.info("Fail.")
});

var layer = new OpenLayers.Layer.Vector("Foo", {
  projection: new OpenLayers.Projection("EPSG:4326"),
  strategies: [fixed],
  protocol: new OpenLayers.Protocol.HTTP({
    url: "/geoserver/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=ns:foo&outputFormat=json&viewparams=foo:var;",
    format: new OpenLayers.Format.GeoJSON()
  })
});