New: Switch to ASPNetCore Kestrel and SignalR

Co-Authored-By: ta264 <ta264@users.noreply.github.com>

src/NzbDrone.Host/WebHost/Middleware/SignalRMiddleware.cs

@@ -0,0 +1,72 @@
+using System;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.Extensions.DependencyInjection;
+using NLog;
+using NzbDrone.Common.Composition;
+using NzbDrone.Core.Configuration;
+using NzbDrone.Host.Middleware;
+using NzbDrone.SignalR;
+
+namespace NzbDrone.Host.Middleware
+{
+    public class SignalRMiddleware : IAspNetCoreMiddleware
+    {
+        private readonly IContainer _container;
+        private readonly Logger _logger;
+        private static string API_KEY;
+        public int Order => 1;
+
+        public SignalRMiddleware(IContainer container,
+                                 IConfigFileProvider configFileProvider,
+                                 Logger logger)
+        {
+            _container = container;
+            _logger = logger;
+            API_KEY = configFileProvider.ApiKey;
+        }
+
+        public void Attach(IApplicationBuilder appBuilder)
+        {
+            appBuilder.UseWebSockets();
+
+            appBuilder.Use(async (context, next) =>
+            {
+                if (context.Request.Path.StartsWithSegments("/signalr") &&
+                    !context.Request.Path.Value.EndsWith("/negotiate"))
+                {
+                    if (!context.Request.Query.ContainsKey("access_token") ||
+                        context.Request.Query["access_token"] != API_KEY)
+                    {
+                        context.Response.StatusCode = 401;
+                        await context.Response.WriteAsync("Unauthorized");
+                        return;
+                    }
+                }
+
+                try
+                {
+                    await next();
+                }
+                catch (OperationCanceledException e)
+                {
+                    // Demote the exception to trace logging so users don't worry (as much).
+                    _logger.Trace(e);
+                }
+            });
+
+            appBuilder.UseSignalR(routes =>
+            {
+                routes.MapHub<MessageHub>("/signalr/messages");
+            });
+
+            // This is a side effect of haing multiple IoC containers, TinyIoC and whatever
+            // Kestrel/SignalR is using. Ideally we'd have one IoC container, but that's non-trivial with TinyIoC
+            // TODO: Use a single IoC container if supported for TinyIoC or if we switch to another system (ie Autofac).
+
+            var hubContext = appBuilder.ApplicationServices.GetService<IHubContext<MessageHub>>();
+            _container.Register(hubContext);
+        }
+    }
+}