Remove the blocking call to Wait in PrepareUpdateServiceAsync

Author: sharwell

src/OpenStack.Net/OpenStack/Services/ContentDelivery/V1/ContentDeliveryClient.cs

@@ -174,40 +174,35 @@ public virtual Task<UpdateServiceApiCall> PrepareUpdateServiceAsync(ServiceId se
             if (serviceId == null)
                 throw new ArgumentNullException("serviceId");
 
-
-
             // At this point, the serviceData parameter contains the NEW (AFTER) version
             // of the service data. Now, we need to retrieve the current (BEFORE) version,
             // then use those to calculate the difference, i.e. the JSON Patch document.
-            var getServiceTask = ContentDeliveryServiceExtensions.GetServiceAsync(this, serviceId, cancellationToken);
-            getServiceTask.Wait();
-            ServiceData originalServiceData = getServiceTask.Result;
-
-
+            return this.GetServiceAsync(serviceId, cancellationToken)
+                .Then(task => PrepareUpdateServiceFromExistingAsync(serviceId, updatedServiceData, task.Result, cancellationToken));
+        }
 
+        protected virtual Task<UpdateServiceApiCall> PrepareUpdateServiceFromExistingAsync(ServiceId serviceId, ServiceData updatedServiceData, ServiceData originalServiceData, CancellationToken cancellationToken)
+        {
             // Here's a serious HACK: Because the current ServiceData includes properties
             // that are not part of a new instance of ServiceData (such as "Id", "Status" and others)
             // we need to create a new instance using the data from the current ServiceData object.
             // That way, when we perform the "DIFF" operation to calculate the JSon Patch object,
             // the extra properties won't interfere.
             ServiceData tempServiceData = new ServiceData(originalServiceData.Name, originalServiceData.FlavorId, originalServiceData.Domains, originalServiceData.Origins, originalServiceData.CachingRules, originalServiceData.Restrictions);
 
-
-
             // Calculate the Json Patch document
             var beforeUpdate = JToken.Parse(JsonConvert.SerializeObject(tempServiceData));
             var afterUpdate = JToken.Parse(JsonConvert.SerializeObject(updatedServiceData));
             var patchDoc = new JsonDiffer().Diff(beforeUpdate, afterUpdate);
 
-
             // Another Hack: For some reason (TODO: which needs to be investigated and fixed),
             // we need to deserialize the document in order for it to render a proper Json object.
             var jsonPatchDocument = JsonConvert.DeserializeObject(patchDoc.ToString());
 
-
             // Now we can call the PATCH method to update the ServiceData on the server.
             UriTemplate template = new UriTemplate("services/{service_id}");
             Dictionary<string, string> parameters = new Dictionary<string, string> { { "service_id", serviceId.Value } };
+
             return GetBaseUriAsync(cancellationToken)
                 .Then(PrepareRequestAsyncFunc(new HttpMethod("PATCH"), template, parameters, jsonPatchDocument, cancellationToken))
                 .Select(