polling for task status.

FarmmapsApi/Extensions.cs

@@ -1,4 +1,7 @@
+using System;
 using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
 using FarmmapsApi.HttpMessageHandlers;
 using FarmmapsApi.Models;
 using FarmmapsApi.Services;
@@ -9,7 +12,8 @@ namespace FarmmapsApi
 {
     public static class Extensions
     {
-        public static IServiceCollection AddFarmmapsServices(this IServiceCollection serviceCollection, Configuration configuration)
+        public static IServiceCollection AddFarmmapsServices(this IServiceCollection serviceCollection,
+            Configuration configuration)
         {
             return serviceCollection
                 .AddSingleton(configuration)
@@ -23,7 +27,26 @@ namespace FarmmapsApi
                 .AddTransient<FarmmapsAuthenticationHandler>()
                 .AddHttpClient<FarmmapsApiService>()
                 .AddHttpMessageHandler<FarmmapsAuthenticationHandler>()
-                .Services;;
+                .Services;
+            ;
+        }
+
+        public static async Task PollTask(TimeSpan retryTime, Func<CancellationTokenSource, Task> callback)
+        {
+            var tokenSource = new CancellationTokenSource();
+            var token = tokenSource.Token;
+            do
+            {
+                try
+                {
+                    await callback(tokenSource);
+                    await Task.Delay(retryTime, token);
+                }
+                catch
+                {
+                    // ignored
+                }
+            } while (!token.IsCancellationRequested);
         }
     }
 }