Add SignalR HUB refresh instead of polling.

BlazorApp1.Application/BlazorApp1.Application.csproj

@@ -8,6 +8,8 @@
 
 	<ItemGroup>
 		<PackageReference Include="AutoMapper" Version="12.0.1" />
+		<PackageReference Include="Microsoft.AspNetCore.Components" Version="7.0.11" />
+		<PackageReference Include="Microsoft.AspNetCore.SignalR.Core" Version="1.1.0" />
 	</ItemGroup>
 
 	<ItemGroup>

BlazorApp1.Application/IWeatherForecastService.cs

@@ -5,5 +5,6 @@ namespace BlazorApp1.Application;
 public interface IWeatherForecastService
 {
     Task AddForecast(WeatherForecastDto weatherForecast, CancellationToken cancellationToken = default);
+    ValueTask ProcessSignalRWeatherSummary(CancellationToken cancellationToken);
     ValueTask ProcessWeatherSummary(WeatherForecast forecast, CancellationToken cancellationToken);
 }

BlazorApp1.Application/WeatherForecastService.cs

@@ -3,6 +3,10 @@
 using BlazorApp1.Domain;
 using BlazorApp1.Domain.Abstractions.Repositories;
 using BlazorApp1.Server.Abstractions.Contracts;
+using BlazorApp1.Server.Hubs;
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.EntityFrameworkCore.Metadata.Internal;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 
@@ -14,18 +18,21 @@ public class WeatherForecastService : IWeatherForecastService
     private readonly IWeatherForecastSummaryRepository _weatherForecastSummaryRepository;
     private readonly IMapper _mapper;
     private readonly IBackgroundTaskQueue _backgroundTaskQueue;
+    private readonly IHubContext<WeatherForecastSummaryHub> hubContext;
     private readonly ILogger<WeatherForecastService> _logger;
 
     public WeatherForecastService(IWeatherForecastRepository weatherForecastRepository,
         IWeatherForecastSummaryRepository weatherForecastSummaryRepository,
         IMapper mapper,
         IBackgroundTaskQueue backgroundTaskQueue,
+        IHubContext<WeatherForecastSummaryHub> hubContext,
         ILogger<WeatherForecastService> logger)
     {
         _weatherForecastRepository = weatherForecastRepository;
         _weatherForecastSummaryRepository = weatherForecastSummaryRepository;
         _mapper = mapper;
         _backgroundTaskQueue = backgroundTaskQueue;
+        this.hubContext = hubContext;
         _logger = logger;
     }
 
@@ -35,7 +42,24 @@ public async Task AddForecast(WeatherForecastDto weatherForecast, CancellationTo
 
         await _weatherForecastRepository.AddWeatherForecast(forecast);
 
-        var tasktoDo = _backgroundTaskQueue.QueueBackgroundWorkItemAsync(ProcessWeatherSummary(forecast));
+        await _backgroundTaskQueue.QueueBackgroundWorkItemAsync(ProcessWeatherSummary(forecast));
+    }
+
+    private static Func<IServiceProvider, CancellationToken, ValueTask> ProcessSignalRWeatherSummary(WeatherForecast forecast)
+    {
+        return (serviceProvider, cancellationToken) =>
+        {
+            var service = serviceProvider.GetRequiredService<IWeatherForecastService>();
+            return service.ProcessSignalRWeatherSummary(cancellationToken);
+        };
+    }
+
+    public async ValueTask ProcessSignalRWeatherSummary(CancellationToken cancellationToken)
+    {
+        //TODO: Move to a new RepoMethod.
+        var forecasts = await _weatherForecastSummaryRepository.GetAllForecastSummaries();
+
+        await this.hubContext.Clients.All.SendAsync("ReceiveForecastSummaries", forecasts.ToArray());
     }
 
     private static Func<IServiceProvider, CancellationToken, ValueTask> ProcessWeatherSummary(WeatherForecast forecast)
@@ -70,6 +94,8 @@ public async ValueTask ProcessWeatherSummary(WeatherForecast forecast, Cancellat
             await _weatherForecastSummaryRepository.AddWeatherForecastSummary(forecastSummary);
         }
 
+        await _backgroundTaskQueue.QueueBackgroundWorkItemAsync(ProcessSignalRWeatherSummary(forecast));
+
         _logger.LogInformation($"Processing ForecastSummary and added {forecast.Date}");
     }
 }

BlazorApp1.Application/WeatherForecastSummaryHub.cs

@@ -0,0 +1,13 @@
+using BlazorApp1.Domain;
+using BlazorApp1.Server.Abstractions.Contracts;
+using Microsoft.AspNetCore.SignalR;
+
+namespace BlazorApp1.Server.Hubs;
+
+public class WeatherForecastSummaryHub : Hub
+{
+    public async Task SendWeatherforecastSummaries(WeatherForecastSummaryDto[] summaries)
+    {
+        await Clients.All.SendAsync("ReceiveForecastSummaries", summaries);
+    }
+}

BlazorApp1/Client/Pages/FetchData.razor

@@ -4,6 +4,8 @@
 @using BlazorApp1.Domain
 @using BlazorApp1.Server.Abstractions.Contracts
 @using System.Text.Json.Serialization;
+@using Microsoft.AspNetCore.SignalR.Client;
+@inject NavigationManager Navigation
 @inject HttpClient Http
 
 <PageTitle>Weather forecast</PageTitle>
@@ -74,7 +76,7 @@ else
     private WeatherForecastDto[]? forecasts;
     private WeatherForecastSummary[]? forecastSummaries;
     private WeatherForecastDto? forecastToAdd;
-    private static System.Timers.Timer _timer;
+    private HubConnection? hubConnection;
 
     protected override async Task OnInitializedAsync()
     {
@@ -84,28 +86,28 @@ else
                 Date = DateTime.Now
             };
 
-        _timer = new System.Timers.Timer(5000);
-        _timer.Elapsed += CountDownTimer;
-        _timer.Enabled = true;
-    }
 
-    public async void CountDownTimer(Object source, System.Timers.ElapsedEventArgs e)
-    {
-        forecastSummaries = await Http.GetFromJsonAsync<WeatherForecastSummary[]>("WeatherForecastSummary");
+        hubConnection = new HubConnectionBuilder()
+           .WithUrl(Navigation.ToAbsoluteUri("/weatherforecastsummaryhub"))
+           .Build();
 
-        await InvokeAsync(async () =>
+        hubConnection.On<WeatherForecastSummary[]>("ReceiveForecastSummaries", (summaries) =>
         {
+            forecastSummaries = summaries;
             StateHasChanged();
         });
+
+        await hubConnection.StartAsync();
     }
+
     private async Task AddForecast()
     {
         if (forecastToAdd != null)
         {
             var response = await Http.PostAsJsonAsync<WeatherForecastDto>("WeatherForecast", forecastToAdd, WeatherForecastDtoJsonContext.Default.WeatherForecastDto);
         }
 
-        await ReloadDataAsync();
+        forecasts = await Http.GetFromJsonAsync<WeatherForecastDto[]>("WeatherForecast", WeatherForecastDtoJsonContext.Default.WeatherForecastDtoArray);
     }
 
     private async Task ReloadDataAsync()

BlazorApp1/Server/Program.cs

@@ -6,7 +6,6 @@
 using BlazorApp1.Server.Profiles;
 using Microsoft.AspNetCore.ResponseCompression;
 using Microsoft.EntityFrameworkCore;
-using System.Text.Encodings.Web;
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -65,6 +64,7 @@
 app.MapControllers();
 
 app.MapHub<ChatHub>("/chathub");
+app.MapHub<WeatherForecastSummaryHub>("/weatherforecastsummaryhub");
 
 app.MapFallbackToFile("index.html");