Refresh / Redraw a Layer in OpenLayers (KML) Network-Link Auto Refresh

Question

TLDR I want to refresh a layer on a timer so it plots the new kml data (like update-link / network link)

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So far I have tried action function as follows:

                function RefreshKMLData(layer) {
                    layer.loaded = false;
                    layer.setVisibility(true);
                    layer.redraw({ force: true });
                }

set interval of the function:

                window.setInterval(RefreshKMLData, 5000, KMLLAYER);

the layer itself:

           var KMLLAYER = new OpenLayers.Layer.Vector("MYKMLLAYER", {
               projection: new OpenLayers.Projection("EPSG:4326"),
               strategies: [new OpenLayers.Strategy.Fixed()],
               protocol: new OpenLayers.Protocol.HTTP({
                   url: MYKMLURL,
                   format: new OpenLayers.Format.KML({
                       extractStyles: true,
                       extractAttributes: true
                   })
               })
           });

the url for KMLLAYER with Math random so it doesnt cache:

var MYKMLURL = var currentanchorpositionurl = 'http://' + host + '/data?_salt=' + Math.random();

I would have thought that this would Refresh the layer. As by setting its loaded to false unloads it. Visibility to true reloads it and with the Math random shouldn't allow it to cache? So has anyone done this before or know how I can get this to work?

Answer 1

Figured seen as it was hard enough for me to find information on this I would add this:

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1)

Create the KML Layer:

            //Defiine your KML layer//
            var MyKmlLayer= new OpenLayers.Layer.Vector("This Is My KML Layer", {
                //Set your projection and strategies//
                projection: new OpenLayers.Projection("EPSG:4326"),
                strategies: [new OpenLayers.Strategy.Fixed()],
                //set the protocol with a url//
                protocol: new OpenLayers.Protocol.HTTP({
                    //set the url to your variable//
                    url: mykmlurl,
                    //format this layer as KML//
                    format: new OpenLayers.Format.KML({
                        //maxDepth is how deep it will follow network links//
                        maxDepth: 1,
                        //extract styles from the KML Layer//
                        extractStyles: true,
                        //extract attributes from the KML Layer//
                        extractAttributes: true
                    })
                })
            });

2)

Set the URL for the KML Layer:

//note that I have host equal to location//   //Math.Random will stop caching//
var mykmlurl = 'http://' + host + '/KML?key=' + Math.random();

3)

Set the interval in which to refresh your layer:

           //function called// //timer// //layer to refresh//
window.setInterval(UpdateKmlLayer, 5000, MyKmlLayer);

4)

The function to update the layer:

            function UpdateKmlLayer(layer) {
                //setting loaded to false unloads the layer//
                layer.loaded = false;
                //setting visibility to true forces a reload of the layer//
                layer.setVisibility(true);
                //the refresh will force it to get the new KML data//
                layer.refresh({ force: true, params: { 'key': Math.random()} });
            }

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Hopes this makes it easier for some others out there.