Access-Control-Allow-Origin Error in Chorme Console

Question

I'm finding that when using 2.0, I get the following error:

MLHttpRequest cannot load http://......../DotNet/proxy.ashx?http://......../ArcGIS/rest/services/Qars/MapServer/0/query. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.

above error shown in chrome and Firefox  Console but work fine in internet explorer.

Can someone please provide me some guidance here?

Thanks!

BhavinSanghani · Answer

Jimmi,

You should be able to see ArcGIS server version on the map service rest endpoint.

As Adrian mentioned, add your arcgis server to esri.config.defaults.io.corsEnabledServers and then the error should go away.

Latest browsers support CORS so, we don't need to do anything for client. To support CORS on arcgis server, you may need to ask your provider to support CORS. What kind of infrastructure they have then accordingly they will have to enable CORS on it. e.g. provider is running arcgis server on windows machine and IIS is the webserver. Then some IIS configuration is required to update (as mentioned on enable-cors.org) so, arcgis server can be enabled for CORS.

I think, with ArcGIS 10.1 onwards we don't need proxy. I have no idea of older versions of arcgis server. You are using old ArcGIS API 2.0 and it might have limited support (not sure). Did you try the same code with the latest version of the API? If no errors with the latest api + same code then I would suspect on the API code.

AdrianMarsden · Answer

This one has cursed me for years - I've still not really sorted it

adding

require(["esri/config"], function (esriConfig) {
            esri.config.defaults.io.corsEnabledServers.push("eddc-gis2");
        });

helps for files that use the API - but I still get it when I create simple pages - the problem is no-one has given me an answer in simple terms what to check for - plus there is at least one Chrome issue logged that indicates this is a misleading error message.

jimmiraza · Answer

Thank You Bhavin for quick response here is your question answers 1) 2.0 means i am using Arcgis javascript 2.0 version 2) yes i am using proxy. without using proxy its work fine 3) arcgis server ( We have purchased services from third party, i am not sure which arcgis server version they are using ) 4) I Am using chorme 41 version and IE 11 version I Am using proxy url. when I am sending post request from chorme or firefox then it shows Access control Allow error. but work fine in internet explorer. Can you please guide me how to send CORS request with proxy url, is it possible? And also guide me how to enable CORS in chrome and firefox. Here is my code. var rings = ring[0]; dojo.parser.parse(); var queryTask = new esri.tasks.QueryTask(url_QARS_Search); esri.config.defaults.io.proxyUrl = url_Proxy; esri.config.defaults.io.alwaysUseProxy = false; //build query filter var query = new esri.tasks.Query(); query.returnGeometry = true; query.outFields = ["*"]; query.geometryType = rings.type; query.geometry = rings; //query.where = search; console.log(query); dojo.connect(queryTask, "onComplete", function (results) { debugger; alert("onComplete"); if (!results) { return; } debugger; var loadGraphics = appLayers.map.graphics.graphics.length == 0; var features = results.features; var infoTemplate = new esri.InfoTemplate("ObjectID : ${OBJECTID}", "${*}"); //add table in div var html = ""; html += ""; html += " "; html += ""; html += ""; html += ""; html += ""; html += " "; //loop thru each graphic feature setting symbols and info templates appLayers.map.centerAt(results.features[0].geometry); dojo.forEach(results.features, function (results) { var graphic = results; var attrs = graphic.attributes; if (true) { debugger; var symbol = new esri.symbol.PictureMarkerSymbol( { "angle": 10, "xoffset": 0, "yoffset": 0, "type": "esriPMS", "url": "img/pin.png", "contentType": "image/png", "width": 30, "height": 30 }); appLayers.map.infoWindow.resize(300, 300); graphic.setInfoTemplate(infoTemplate); graphic.setSymbol(symbol); appLayers.map.graphics.add(graphic); html += " "; html += ""; html += ""; html += ""; html += ""; html += " "; } }); html += "

OBJECTID	ZONE_NO	STREET_NO	BUILDING_NO
" + attrs.OBJECTID + "	" + attrs.ZONE_NO + "	" + attrs.STREET_NO + "	" + attrs.BUILDING_NO + "

"; document.getElementById("gvlandmark").innerHTML = html; }); dojo.connect(queryTask, "onError", function (errorRes) { alert("erro" + errorRes); }); //execute the query queryTask.execute(query);