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<p style="margin-bottom: 0in">Hello List,</p>
<p style="margin-bottom: 0in">at first i wanna thanks for the great work your team is doing. I really enjoy using OpenLayers and his nice features to create a good user experience. Right now i am building a sdi for a big amount of raster data. I publish the raster data via WMS (their access is right now restricted). At the client side i am using OpenLayers for displaying the data. This runs in most cases quite good. But sometimes and especially in Chromium i run in some timeout issues.</p>
<p style="margin-bottom: 0in"><u><strong>The Case:</strong></u></p>
<p style="margin-bottom: 0in">OpenLayers try to send the WMS Request to server.</p>
<p style="margin-bottom: 0in"><strong>Request URL:</strong></p>
<p style="margin-bottom: 0in"><a href="http://194.95.145.43/cgi-bin/sachsen_wms?LAYERS=sachsen-default&TYPE=png&FORMAT=image%2Fpng&TRANSPARENT=true&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A900913&BBOX=1586191.7052772,6531373.4798253,1742734.7391834,6687916.5137316&WIDTH=256&HEIGHT=256R">service_url?LAYERS=sachsen-default&TYPE=png&FORMAT=image%2Fpng&TRANSPARENT=true&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A900913&BBOX=1586191.7052772,6531373.4798253,1742734.7391834,6687916.5137316&WIDTH=256&HEIGHT=256</a></p>
<p style="margin-bottom: 0in"><strong>Request Headers:</strong></p>
<p style="margin-bottom: 0in">Cache-Control: no-cache</p>
<p style="margin-bottom: 0in">Pragma: no-cache</p>
<p style="margin-bottom: 0in">Referer: <a href="http://localhost/client.html">http://localhost/client.html</a></p>
<p style="margin-bottom: 0in">User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.22 (KHTML, like Gecko) Ubuntu Chromium/25.0.1364.160 Chrome/25.0.1364.160 Safari/537.22</p>
<p style="margin-bottom: 0in"><strong>Query String Parameters:</strong></p>
<p style="margin-bottom: 0in">LAYERS: sachsen-default</p>
<p style="margin-bottom: 0in">TYPE: png</p>
<p style="margin-bottom: 0in">FORMAT: image/png</p>
<p style="margin-bottom: 0in">TRANSPARENT: true</p>
<p style="margin-bottom: 0in">SERVICE: WMS</p>
<p style="margin-bottom: 0in">VERSION: 1.1.1</p>
<p style="margin-bottom: 0in">REQUEST: GetMap</p>
<p style="margin-bottom: 0in">STYLES:</p>
<p style="margin-bottom: 0in">SRS: EPSG:900913</p>
<p style="margin-bottom: 0in">BBOX: 1586191.7052772,6531373.4798253,1742734.7391834,6687916.5137316</p>
<p style="margin-bottom: 0in">WIDTH: 256</p>
<p style="margin-bottom: 0in">HEIGHT: 256</p>
<p style="margin-bottom: 0in">This request seems to timeout than (server log: serverip - - [09/Jul/2013:19:58:24 +0200] "-" 408 0 "-" "-" ) and openlayers displays than pink tiles. I was able to handle this by setting up the OpenLayers parameter “OpenLayers.IMAGE_RELOAD_ATTEMPTS” to 5. After that modification OpenLayers is getting the map tiles through a new request-attempt after a timeout. This solution works, but it extremly slows down the hole application in cases of timeout issues.</p>
<p style="margin-bottom: 0in">This timeout issues appear consistently often in Chromium. In Firefox they seem to disappear. My question is now, if anybody knows this problem and if there exist a solution for it.</p>
<p style="margin-bottom: 0in">In case of question, here are some code snippets about my OpenLayers (Version: http://openlayers.org/api/OpenLayers.js) application:</p>
<p style="margin-bottom: 0in">var options = {</p>
<p style="margin-bottom: 0in">projection: new OpenLayers.Projection("EPSG:900913"),</p>
<p style="margin-bottom: 0in">displayProjection: new OpenLayers.Projection("EPSG:4326"),</p>
<p style="margin-bottom: 0in">units: "m",</p>
<p style="margin-bottom: 0in">maxResolution: 4891.9698093750003,</p>
<p style="margin-bottom: 0in">maxExtent: bounds,</p>
<p style="margin-bottom: 0in">controls: [</p>
<p style="margin-bottom: 0in">new OpenLayers.Control.Navigation(),</p>
<p style="margin-bottom: 0in">new OpenLayers.Control.LayerSwitcher(),</p>
<p style="margin-bottom: 0in">new OpenLayers.Control.PanZoomBar(),</p>
<p style="margin-bottom: 0in">new OpenLayers.Control.Attribution(),</p>
<p style="margin-bottom: 0in">new OpenLayers.Control.MousePosition(),</p>
<p style="margin-bottom: 0in">//new OpenLayers.Control.ScaleLine({geodesic:true})</p>
<p style="margin-bottom: 0in">]</p>
<p style="margin-bottom: 0in">};</p>
<p style="margin-bottom: 0in">map = new OpenLayers.Map('mapdiv', options);</p>
<p style="margin-bottom: 0in"> </p>
<p style="margin-bottom: 0in">layerSachsen_default = new OpenLayers.Layer.WMS("Sachsen (default)",</p>
<p style="margin-bottom: 0in">"wms_url",</p>
<p style="margin-bottom: 0in">{</p>
<p style="margin-bottom: 0in">layers: "sachsen-default",</p>
<p style="margin-bottom: 0in">type: "png",</p>
<p style="margin-bottom: 0in">format: "image/png",</p>
<p style="margin-bottom: 0in">transparent: 'true'</p>
<p style="margin-bottom: 0in">},{</p>
<p style="margin-bottom: 0in">isBaseLayer: false,</p>
<p style="margin-bottom: 0in">opacity: 0.85,</p>
<p style="margin-bottom: 0in">visibility: true</p>
<p style="margin-bottom: 0in">}</p>
<p style="margin-bottom: 0in">);</p>
<p style="margin-bottom: 0in"> </p>
<p style="margin-bottom: 0in">Kind regards,</p>
<p style="margin-bottom: 0in">JM</p>
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