esri.request - wait till response

AdrianMarsden

Hi

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

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

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

AdrianMarsden

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 maphttps://community.esri.com/thread/65042