Ansynchronous HTTP 202 support + user cancellation

CHANGES.md

@@ -6,6 +6,7 @@ Change Log
 * Fixed a bug that could cause tiles to be missing from the globe surface, especially when starting with the camera zoomed close to the surface.
 * Added support for refreshing expired tokens for `ArcGisMapServerImageryProvider` via callback registered with `options.requestNewToken` in constructor.
 * Added support for `parameters` to `ArcGisMapServerImageryProvider`.
+* Added Support for HTTP 202 headers, and cancelling them if the request object is marked as cancelled.
 
 ### 1.46 - 2018-06-01
 

Source/Core/Resource.js

@@ -1260,10 +1260,11 @@ define([
  var timeout = options.timeout;
  var data = options.data;
  var deferred = when.defer();
- var xhr = Resource._Implementations.loadWithXhr(resource.url, responseType, method, data, headers, deferred, overrideMimeType, timeout);
+ var xhr = Resource._Implementations.loadWithXhr(resource.url, responseType, method, data, headers, deferred, overrideMimeType, timeout, request);
  if (defined(xhr) && defined(xhr.abort)) {
  request.cancelFunction = function() {
  xhr.abort();
+ request.cancel();
  };
  }
  return deferred.promise;
@@ -1893,7 +1894,7 @@ define([
  }).end();
  }
 
- Resource._Implementations.loadWithXhr = function(url, responseType, method, data, headers, deferred, overrideMimeType, timeout) {
+ Resource._Implementations.loadWithXhr = function(url, responseType, method, data, headers, deferred, overrideMimeType, timeout, request) {
  var dataUriRegexResult = dataUriRegex.exec(url);
  if (dataUriRegexResult !== null) {
  deferred.resolve(decodeDataUri(dataUriRegexResult, responseType));
@@ -1969,6 +1970,31 @@ define([
  if (xhr.status === 204) {
  // accept no content
  deferred.resolve();
+ } else if (xhr.status === 202) {
+ //HTTP 202 is for a process that can take a while
+ //contains at minimum a location to get the 
+ //completed resource from
+ //and the permission to read the location
+ var newURL = xhr.getResponseHeader('Location');
+ if (newURL === undefined || newURL === null || newURL === "") {
+ deferred.reject(new RuntimeError("HTTP 202 header with no Location.\n Contact the service owner directly about this misconfiguration.\n Using HTTP 202 responses requires 'Location' and 'Access-Control-Expose-Headers: Location' headers in the response"));
+ return;
+ }
+ //if request still valid change url and call this function
+ if (!request.cancelled) {
+ var newXHR;
+ setTimeout(function(){
+ if (!request.cancelled){
+ newXHR = Resource._Implementations.loadWithXhr.call(this,newURL, responseType, method, data, headers, deferred, overrideMimeType, timeout, request);
+ } else {
+ //user cancel request after waking from sleep
+ return;
+ }
+ },10000);
+ return newXHR
+ } else {
+ return;//request has been cancelled by user before sleep
+ }
  } else if (defined(xhr.response) && (!defined(responseType) || (browserResponseType === responseType))) {
  deferred.resolve(response);
  } else if ((responseType === 'json') && typeof response === 'string') {