FarmMapsApiClient/FarmmapsApi/Extensions.cs

using System;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using FarmmapsApi.HttpMessageHandlers;
using FarmmapsApi.Models;
using FarmmapsApi.Services;
using IdentityModel.Client;
using Microsoft.Extensions.DependencyInjection;

namespace FarmmapsApi
{
    public static class Extensions
    {
        public static IServiceCollection AddFarmmapsServices(this IServiceCollection serviceCollection,
            Configuration configuration)
        {
            return serviceCollection
                .AddSingleton(configuration)
                .AddSingleton<IDiscoveryCache>(sp =>
                {
                    var httpFactory = sp.GetRequiredService<IHttpClientFactory>();
                    return new DiscoveryCache(configuration.DiscoveryEndpointUrl,
                        () => httpFactory.CreateClient());
                })
                .AddSingleton<HttpClientSettings>()
                .AddSingleton<FarmmapsEventHub>()
                .AddTransient<OpenIdConnectService>()
                .AddTransient<FarmmapsAuthenticationHandler>()
                .AddHttpClient<FarmmapsApiService>()
                .AddHttpMessageHandler<FarmmapsAuthenticationHandler>()
                .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
                {
                    tokenSource.Cancel();
                }
            } while (!token.IsCancellationRequested);
        }
    }
}