esri.request - wait till response

AdrianMarsden — Sun, 12 Dec 2021 00:01:43 GMT

I have an awful web app that is mainly legacy code I wrote many years back, but functions and the users use it all the time

WE're moving stuff around and at the moment the desktops are at a different site to the data so I'm hitting latency issues.

I have this code

            //return the layer descriptions and © text into arrays - we use this later for the info dialog to generate hyperlinks and © text
            dojo.forEach(dynamicMapServiceLayer.layerInfos, function (layer) {
                var requestHandle = esri.request({
                    url: mapservice2 + "/" + layer.id + "?f=json",
                    handleAs: "json",
                    load: function (data) {
                        LayerAttach[layer.id] = data.hasAttachments;
                        console.debug(dynamicMapServiceLayer.layerInfos[layer.id])
                        LayerDescriptions[layer.id] = data.description;
                    
                        dynamicMapServiceLayer.layerInfos[layer.id].copyrightText = data.copyrightText;
                        
                    },
                }, { useProxy: true });
            });‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Which I have on the Onload event of the main dynamic map It reads extra stuff from the rest data of the service that I use to create hyperlinks (as good old ArcIMS did)

All worked fine until this latency hit. I have a sub-site that on start up takes a feature passed in the URL, finds the extent of that feature, then passes that into a ID task on the main service. The output uses the arrays/data produced in the above routine. With the latency I am getting results of the ID task back before I get all the info from the above code.

I have vague knowledge of defers and the like so surely I should add to each loop above a wait until the data is back until stepping forward, or a wait until everything is back

Any advice welcomed.

In the short term I've given those users who use this sub-site Chrome, which can handle things faster and not get caught up.

Cheers

ACM

Re: esri.request - wait till response

RobertScheitlin__GISP — Sun, 12 Dec 2021 00:01:46 GMT

Adrian,

To work with deferred you use .then to execute something after the deferred is returned:

requestHandle.then(function(evt){
   //now do something
});

you also may want to consider dojo/promise/all if that is available in the version of the API you are using

dojo/promise/all — The Dojo Toolkit - Reference Guide

Re: esri.request - wait till response

AdrianMarsden — Mon, 13 Mar 2017 10:44:33 GMT

Thanks - that is helpful and it helps me understand a bit more. However, I really need to wrap the entire onLoad function up to give it a "then" - I've got to move onto other stuff right now, but I've just found this post https://community.esri.com/thread/30458 which looks super useful. This one also looks promising Connect to onExtentChange with deferred web map https://community.esri.com/thread/65042

topic Re: esri.request - wait till response in ArcGIS JavaScript Maps SDK Questions

esri.request - wait till response

Re: esri.request - wait till response

Re: esri.request - wait till response