Winify – Diff between revs 64 and 66

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 ï»¿using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Drawing;
 using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Runtime.Caching;
 using System.Runtime.CompilerServices;
 using System.Security.Authentication;
 using System.Security.Cryptography.X509Certificates;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Threading.Tasks.Dataflow;
 using System.Windows.Forms;
 using Newtonsoft.Json;
+using Org.BouncyCastle.Asn1.Pkcs;
 using Serilog;
 using Servers;
 using WebSocketSharp;
 using WebSocketSharp.Net;
 using Winify.Utilities;
 using ErrorEventArgs = WebSocketSharp.ErrorEventArgs;
 using NetworkCredential = System.Net.NetworkCredential;
 namespace Winify.Gotify
+{
     public class GotifyConnection : IDisposable
+    {
         #region Public Events & Delegates
         public event EventHandler<GotifyNotificationEventArgs> GotifyNotification;
         #endregion
         #region Private Delegates, Events, Enums, Properties, Indexers and Fields
         private readonly Server _server;
         private CancellationToken _cancellationToken;
         private CancellationTokenSource _cancellationTokenSource;
-        private Task _runTask;
+        private Task _heartBeatTask;
         private HttpClient _httpClient;
         private readonly Uri _webSocketsUri;
         private readonly Uri _httpUri;
         private WebSocket _webSocketSharp;
         private readonly Configuration.Configuration _configuration;
-        private Task _initTask;
         private IDisposable _tplRetrievePastMessagesLink;
         private IDisposable _tplWebSocketsBufferBlockTransformLink;
         private IDisposable _tplWebSocketsTransformActionLink;
         private IDisposable _tplWebSocketsTransformActionNullLink;
-        private readonly BufferBlock<byte[]> _webSocketMessageBufferBlock;
+        private readonly BufferBlock<GotifyConnectionData> _webSocketMessageBufferBlock;
         private readonly Stopwatch _webSocketsClientPingStopWatch;
         private readonly ScheduledContinuation _webSocketsServerResponseScheduledContinuation;
+        private Task _retrievePastMessagesTask;
+        private static JsonSerializer _jsonSerializer;
         private readonly MemoryCache _applicationImageCache;
         #endregion
         #region Constructors, Destructors and Finalizers
         private GotifyConnection()
+        {
-            _applicationImageCache = new MemoryCache("GotifyApplicationImageCache");
+            _jsonSerializer = new JsonSerializer();
             _webSocketsServerResponseScheduledContinuation = new ScheduledContinuation();
             _webSocketsClientPingStopWatch = new Stopwatch();
+            _webSocketMessageBufferBlock = new BufferBlock<GotifyConnectionData>(
+                new DataflowBlockOptions
+                {
+                    CancellationToken = _cancellationToken
+                });
-            _webSocketMessageBufferBlock = new BufferBlock<byte[]>(new DataflowBlockOptions { CancellationToken = _cancellationToken });
-            var webSocketTransformBlock = new TransformBlock<byte[], GotifyMessage>(bytes =>
+            var webSocketTransformBlock = new TransformBlock<GotifyConnectionData, GotifyMessage>(data =>
             {
-                if (bytes.Length == 0)
+                if (data.Payload == null || data.Payload.Length == 0)
+                {
                     return null;
+                }
-                var message = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
                 GotifyMessage gotifyNotification;
                 try
+                {
+                    var message = Encoding.UTF8.GetString(data.Payload, 0, data.Payload.Length);
                     gotifyNotification = JsonConvert.DeserializeObject<GotifyMessage>(message);
-                }
-                catch (JsonSerializationException exception)
-                {
-                    Log.Warning($"Could not deserialize notification: {exception.Message}");
+                    if (gotifyNotification == null)
+                    {
-                    return null;
+                        throw new ArgumentNullException();
-                }
+                    }
+                    gotifyNotification.Server = data.Server;
+                }
-                if (gotifyNotification == null)
+                catch (Exception exception)
+                {
-                    Log.Warning($"Could not deserialize gotify notification: {message}");
+                    Log.Warning(exception, "Could not deserialize notification.");
                     return null;
+                }
                 return gotifyNotification;
             }, new ExecutionDataflowBlockOptions { CancellationToken = _cancellationToken });
             var webSocketActionBlock = new ActionBlock<GotifyMessage>(async message =>
+            {
-                message.Server = _server;
-                var cachedImage = _applicationImageCache.Get($"{message.AppId}");
+                using var imageStream = await RetrieveGotifyApplicationImage(message.AppId, _cancellationToken);
-                if (cachedImage is Stream cachedImageStream)
+                if (imageStream == null || imageStream.Length == 0)
+                {
-                    using var cachedImageMemoryStream = new MemoryStream();
-                    await cachedImageStream.CopyToAsync(cachedImageMemoryStream);
-                    var cachedApplicationImage = new Bitmap(cachedImageMemoryStream);
-                    GotifyNotification?.Invoke(this,
-                        new GotifyNotificationEventArgs(message, cachedApplicationImage));
+                    Log.Warning("Could not find any application image for notification.");
                     return;
+                }
-                using var imageStream = await RetrieveGotifyApplicationImage(message.AppId, _cancellationToken);
-                    if (imageStream == null || imageStream.Length == 0)
-                    {
-                        Log.Warning("Could not find any application image for notification");
-                        return;
-                    }
-                    using var memoryStream = new MemoryStream();
-                    await imageStream.CopyToAsync(memoryStream);
-                    var imageBytes = memoryStream.ToArray();
-                    _applicationImageCache.Add($"{message.AppId}", imageBytes,
-                        new CacheItemPolicy
-                        {
-                            SlidingExpiration = TimeSpan.FromHours(1)
-                        });
-                    var image = new Bitmap(memoryStream);
+                var image = new Bitmap(imageStream);
-                    GotifyNotification?.Invoke(this,
+                GotifyNotification?.Invoke(this,
-                        new GotifyNotificationEventArgs(message, image));
+                    new GotifyNotificationEventArgs(message, image));
                 Log.Debug($"Notification message received: {message.Message}");
             }, new ExecutionDataflowBlockOptions { CancellationToken = _cancellationToken });
             _tplWebSocketsBufferBlockTransformLink = _webSocketMessageBufferBlock.LinkTo(webSocketTransformBlock,
                 new DataflowLinkOptions { PropagateCompletion = true });
             _tplWebSocketsTransformActionLink = webSocketTransformBlock.LinkTo(webSocketActionBlock,
                 new DataflowLinkOptions { PropagateCompletion = true }, message => message != null);
             _tplWebSocketsTransformActionNullLink = webSocketTransformBlock.LinkTo(DataflowBlock.NullTarget<GotifyMessage>(),
                 new DataflowLinkOptions() { PropagateCompletion = true });
+        }
         public GotifyConnection(Server server, Configuration.Configuration configuration) : this()
+        {
             _server = server;
             _configuration = configuration;
             ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
             var httpClientHandler = new HttpClientHandler
+            {
                 // mono does not implement this
                 //SslProtocols = SslProtocols.Tls12
             };
             _httpClient = new HttpClient(httpClientHandler);
             if (_configuration.IgnoreSelfSignedCertificates)
                 httpClientHandler.ServerCertificateCustomValidationCallback =
                     (httpRequestMessage, cert, cetChain, policyErrors) => true;
             if (_configuration.Proxy.Enable)
                 httpClientHandler.Proxy = new WebProxy(_configuration.Proxy.Url, false, new string[] { },
                     new NetworkCredential(_configuration.Proxy.Username, _configuration.Proxy.Password));
             _httpClient = new HttpClient(httpClientHandler);
             if (!string.IsNullOrEmpty(_server.Username) && !string.IsNullOrEmpty(_server.Password))
                 _httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",
                     Convert.ToBase64String(Encoding.Default.GetBytes($"{_server.Username}:{_server.Password}")));
             if (!Uri.TryCreate(_server.Url, UriKind.Absolute, out _httpUri))
+            {
                 Log.Error($"No HTTP URL could be built out of the supplied server URI {_server.Url}");
                 return;
+            }
             // Build the web sockets URI.
             var webSocketsUriBuilder = new UriBuilder(_httpUri);
             switch (webSocketsUriBuilder.Scheme.ToUpperInvariant())
+            {
                 case "HTTP":
                     webSocketsUriBuilder.Scheme = "ws";
                     break;
                 case "HTTPS":
                     webSocketsUriBuilder.Scheme = "wss";
                     break;
+            }
-            try
-            {
-                webSocketsUriBuilder.Path = Path.Combine(webSocketsUriBuilder.Path, "stream");
-            }
-            catch (ArgumentException exception)
+            if (!Uri.TryCreate(webSocketsUriBuilder.Uri, "stream", out var combinedUri))
-            {
-                Log.Error(
+            {
-                    $"No WebSockets URL could be built from the provided URL {_server.Url} due to {exception.Message}");
+                Log.Error($"No WebSockets URL could be built from the provided URL {_server.Url}.");
             }
-            _webSocketsUri = webSocketsUriBuilder.Uri;
+            _webSocketsUri = combinedUri;
+        }
         public void Dispose()
+        {
             if (_cancellationTokenSource != null)
+            {
                 _cancellationTokenSource.Dispose();
                 _cancellationTokenSource = null;
+            }
             if (_tplWebSocketsBufferBlockTransformLink != null)
+            {
                 _tplWebSocketsBufferBlockTransformLink.Dispose();
                 _tplWebSocketsBufferBlockTransformLink = null;
+            }
             if (_tplWebSocketsTransformActionLink != null)
+            {
                 _tplWebSocketsTransformActionLink.Dispose();
                 _tplWebSocketsTransformActionLink = null;
+            }
             if (_tplWebSocketsTransformActionNullLink != null)
+            {
                 _tplWebSocketsTransformActionNullLink.Dispose();
                 _tplWebSocketsTransformActionNullLink = null;
+            }
             if (_tplRetrievePastMessagesLink != null)
+            {
                 _tplRetrievePastMessagesLink.Dispose();
                 _tplRetrievePastMessagesLink = null;
+            }
             if (_webSocketSharp != null)
+            {
                 _webSocketSharp.Close();
                 _webSocketSharp = null;
+            }
             if (_httpClient != null)
+            {
                 _httpClient.Dispose();
                 _httpClient = null;
+            }
+        }
         #endregion
         #region Public Methods
         public void Start()
+        {
             if (_webSocketsUri == null || _httpUri == null)
+            {
                 Log.Error("Could not start connection to server due to unreadable URLs");
                 return;
+            }
             _cancellationTokenSource = new CancellationTokenSource();
             _cancellationToken = _cancellationTokenSource.Token;
-            Connect();
-            if (_configuration.RetrievePastNotificationHours != 0)
+            if (_webSocketSharp != null)
             {
-                _initTask = RetrievePastMessages(_cancellationToken);
+                return;
-            }
-            _runTask = HeartBeat(_cancellationToken);
-        }
         private void Connect()
             _webSocketSharp = new WebSocket(_webSocketsUri.AbsoluteUri);
             _webSocketSharp.EmitOnPing = true;
             _webSocketSharp.WaitTime = TimeSpan.FromMinutes(1);
             _webSocketSharp.SslConfiguration = new ClientSslConfiguration(_webSocketsUri.Host,
                 new X509CertificateCollection(new X509Certificate[] { }), SslProtocols.Tls12, false);
             if (_configuration.Proxy.Enable)
                 _webSocketSharp.SetProxy(_configuration.Proxy.Url, _configuration.Proxy.Username,
                     _configuration.Proxy.Password);
             if (!string.IsNullOrEmpty(_server.Username) && !string.IsNullOrEmpty(_server.Password))
                 _webSocketSharp.SetCredentials(_server.Username, _server.Password, true);
             if (_configuration.IgnoreSelfSignedCertificates)
                 _webSocketSharp.SslConfiguration.ServerCertificateValidationCallback +=
                     (sender, certificate, chain, errors) => true;
             _webSocketSharp.Log.Output = (logData, s) =>
+            {
                 Log.Information($"WebSockets low level logging reported: {logData.Message}");
             };
             _webSocketSharp.OnMessage += WebSocketSharp_OnMessage;
             _webSocketSharp.OnError += WebSocketSharp_OnError;
             _webSocketSharp.OnOpen += WebSocketSharp_OnOpen;
             _webSocketSharp.OnClose += WebSocketSharp_OnClose;
+            _webSocketSharp.Connect();
+            _heartBeatTask = HeartBeat(_cancellationToken);
+            if (_configuration.RetrievePastNotificationHours != 0)
+            {
+                _retrievePastMessagesTask = RetrievePastMessages(_cancellationToken);
             _webSocketSharp.ConnectAsync();
+        }
         private void WebSocketSharp_OnClose(object sender, CloseEventArgs e)
+        {
             Log.Information(
                 $"WebSockets connection to server {_webSocketsUri.AbsoluteUri} closed with reason {e.Reason}");
+        }
         private void WebSocketSharp_OnOpen(object sender, EventArgs e)
+        {
             Log.Information($"WebSockets connection to server {_webSocketsUri.AbsoluteUri} is now open");
             _webSocketsServerResponseScheduledContinuation.Schedule(TimeSpan.FromMinutes(1), OnUnresponsiveServer, _cancellationToken);
+        }
         private void OnUnresponsiveServer()
+        {
             Log.Warning($"Server {_server} has not responded in a long while...");
+        }
         private async void WebSocketSharp_OnError(object sender, ErrorEventArgs e)
+        {
             Log.Error(
                 $"Connection to WebSockets server {_webSocketsUri.AbsoluteUri} terminated unexpectedly with message {e.Message}",
                 e.Exception);
-            if (_cancellationToken.IsCancellationRequested)
-            {
-                Stop();
-                return;
-            }
             await Task.Delay(TimeSpan.FromSeconds(1), _cancellationToken);
             Log.Information($"Reconnecting to websocket server {_webSocketsUri.AbsoluteUri}");
-            Connect();
+            await Stop().ContinueWith(task => Start(), CancellationToken.None);
+        }
         private async void WebSocketSharp_OnMessage(object sender, MessageEventArgs e)
+        {
             if (e.IsPing)
+            {
                 Log.Information($"Server {_server} sent PING message");
                 _webSocketsServerResponseScheduledContinuation.Schedule(TimeSpan.FromMinutes(1), OnUnresponsiveServer, _cancellationToken);
                 return;
+            }
-            await _webSocketMessageBufferBlock.SendAsync(e.RawData, _cancellationToken);
+            await _webSocketMessageBufferBlock.SendAsync(new GotifyConnectionData(e.RawData, _server), _cancellationToken);
         }
+        public async Task Stop()
-        public void Stop()
+        {
+            if (_webSocketSharp == null || _cancellationTokenSource == null)
+            {
                 return;
+            }
+            _cancellationTokenSource.Cancel();
+            await _heartBeatTask;
+            await _retrievePastMessagesTask;
+            if (_webSocketSharp != null)
+            {
+                _webSocketSharp.OnMessage -= WebSocketSharp_OnMessage;
+                _webSocketSharp.OnError -= WebSocketSharp_OnError;
+                _webSocketSharp.OnOpen -= WebSocketSharp_OnOpen;
+                _webSocketSharp.OnClose -= WebSocketSharp_OnClose;
+                _webSocketSharp.Close();
+                _webSocketSharp = null;
+            }
             if (_cancellationTokenSource == null) return;
             _cancellationTokenSource.Dispose();
-            _cancellationTokenSource.Cancel();
+            _cancellationTokenSource = null;
+        }
         #endregion
         #region Private Methods
         private async Task RetrievePastMessages(CancellationToken cancellationToken)
+        {
-            var messageUriBuilder = new UriBuilder(_httpUri);
-            var gotifyApplicationBufferBlock = new BufferBlock<GotifyApplication>(new DataflowBlockOptions { CancellationToken = cancellationToken });
+            var gotifyApplicationBufferBlock = new BufferBlock<GotifyConnectionApplication>(new DataflowBlockOptions { CancellationToken = cancellationToken });
-            var gotifyApplicationActionBlock = new ActionBlock<GotifyApplication>(async application =>
+            var gotifyApplicationActionBlock = new ActionBlock<GotifyConnectionApplication>(async gotifyConnectionApplication =>
+            {
-                try
-                {
-                    messageUriBuilder.Path = Path.Combine(messageUriBuilder.Path, "application", $"{application.Id}",
+                if (!Uri.TryCreate(_httpUri, $"application/{gotifyConnectionApplication.Application.Id}/message", out var combinedUri))
-                        "message");
-                }
-                catch (ArgumentException exception)
+                {
-                    Log.Error($"No application URL could be built for {_server.Url} due to {exception.Message}");
+                    Log.Error($"Could not get application message Uri {gotifyConnectionApplication.Application.Id}.");
                     return;
+                }
-                HttpResponseMessage messagesResponse;
+                GotifyMessageQuery gotifyMessageQuery;
                 try
                 {
+                    using var messageStream = await _httpClient.GetStreamAsync(combinedUri);
+                    using var streamReader = new StreamReader(messageStream);
+                    using var jsonTextReader = new JsonTextReader(streamReader);
-                    messagesResponse = await _httpClient.GetAsync(messageUriBuilder.Uri, cancellationToken);
+                    gotifyMessageQuery = _jsonSerializer.Deserialize<GotifyMessageQuery>(jsonTextReader);
                 }
-                catch (Exception exception)
+                catch (HttpRequestException exception)
                 {
-                    Log.Error($"Could not get application {application.Id} due to {exception.Message}");
+                    Log.Warning(exception, $"Could not get application {gotifyConnectionApplication.Application.Id}.");
                     return;
+                }
-                var messages = await messagesResponse.Content.ReadAsStringAsync();
-                GotifyMessageQuery gotifyMessageQuery;
-                try
-                {
-                    gotifyMessageQuery =
-                        JsonConvert.DeserializeObject<GotifyMessageQuery>(messages);
-                }
                 catch (JsonSerializationException exception)
+                {
-                    Log.Warning($"Could not deserialize the message response: {exception.Message}");
+                    Log.Warning(exception,$"Could not deserialize the message response for application {gotifyConnectionApplication.Application.Id}.");
                     return;
+                }
-                foreach (var message in gotifyMessageQuery.Messages.Where(message => message.Date >= DateTime.Now - TimeSpan.FromHours(_configuration.RetrievePastNotificationHours)))
+                if (gotifyMessageQuery == null || gotifyMessageQuery.Messages == null)
-                {
-                    message.Server = _server;
+                {
-                    var cachedImage = _applicationImageCache.Get($"{message.AppId}");
-                    if (cachedImage is Stream cachedImageStream)
-                    {
-                        using var cachedImageMemoryStream = new MemoryStream();
-                        await cachedImageStream.CopyToAsync(cachedImageMemoryStream);
+                    Log.Warning("Invalid application messages deserialized deserialized.");
-                        var cachedApplicationImage = new Bitmap(cachedImageMemoryStream);
+                    return;
+                }
+                foreach (var message in gotifyMessageQuery.Messages)
-                        GotifyNotification?.Invoke(this,
+                {
-                            new GotifyNotificationEventArgs(message, cachedApplicationImage));
+                    if (message.Date < DateTime.Now - TimeSpan.FromHours(_configuration.RetrievePastNotificationHours))
+                    {
-                        return;
+                        continue;
-                    }
+                    }
                     using var imageStream = await RetrieveGotifyApplicationImage(message.AppId, _cancellationToken);
+                    using var imageStream = await RetrieveGotifyApplicationImage(message.AppId, _cancellationToken);
+                    if (imageStream == null || imageStream.Length == 0)
                     if (imageStream == null || imageStream.Length == 0)
                         Log.Warning("Could not find any application image for notification.");
                         Log.Warning("Could not find any application image for notification");
                         continue;
+                    }
-                    using var memoryStream = new MemoryStream();
-                    await imageStream.CopyToAsync(memoryStream);
-                    var imageBytes = memoryStream.ToArray();
-                    _applicationImageCache.Add($"{message.AppId}", imageBytes,
-                        new CacheItemPolicy
-                        {
-                            SlidingExpiration = TimeSpan.FromHours(1)
-                        });
+                    var image = new Bitmap(imageStream);
-                    var image = new Bitmap(memoryStream);
+                    message.Server = gotifyConnectionApplication.Server;
                     GotifyNotification?.Invoke(this,
                         new GotifyNotificationEventArgs(message, image));
+                }
             }, new ExecutionDataflowBlockOptions { CancellationToken = cancellationToken });
             gotifyApplicationBufferBlock.LinkTo(gotifyApplicationActionBlock,
                 new DataflowLinkOptions { PropagateCompletion = true });
             var tasks = new ConcurrentBag<Task>();
             await foreach (var application in RetrieveGotifyApplications(cancellationToken))
+            {
-            {
+                var gotifyConnectionApplication = new GotifyConnectionApplication(_server, application);
-                await gotifyApplicationBufferBlock.SendAsync(application, cancellationToken);
+                tasks.Add(gotifyApplicationBufferBlock.SendAsync(gotifyConnectionApplication, cancellationToken));
+            }
             await Task.WhenAll(tasks);
             gotifyApplicationBufferBlock.Complete();
             await gotifyApplicationActionBlock.Completion;
+        }
         private async Task HeartBeat(CancellationToken cancellationToken)
+        {
             try
+            {
                 do
+                {
                     await Task.Delay(TimeSpan.FromMinutes(1), cancellationToken);
                     _webSocketsClientPingStopWatch.Restart();
                     if (!_webSocketSharp.Ping())
+                    {
                         Log.Warning($"Server {_server} did not respond to PING message.");
                         continue;
+                    }
                     var delta = _webSocketsClientPingStopWatch.ElapsedMilliseconds;
                     Log.Information($"PING response latency for {_server} is {delta}ms");
                     _webSocketsServerResponseScheduledContinuation.Schedule(TimeSpan.FromMinutes(1), OnUnresponsiveServer, _cancellationToken);
                 } while (!cancellationToken.IsCancellationRequested);
+            }
             catch (Exception exception) when (exception is OperationCanceledException ||
                                               exception is ObjectDisposedException)
+            {
+            }
             catch (Exception exception)
+            {
                 Log.Warning(exception, $"Heartbeat for server {_server} has failed due to {exception.Message}");
+            }
+        }
         private async IAsyncEnumerable<GotifyApplication> RetrieveGotifyApplications([EnumeratorCancellation] CancellationToken cancellationToken)
+        {
-            var applicationsUriBuilder = new UriBuilder(_httpUri);
+            if (!Uri.TryCreate(_httpUri, "application", out var combinedUri))
-            try
-            {
-                applicationsUriBuilder.Path = Path.Combine(applicationsUriBuilder.Path, "application");
-            }
-            catch (ArgumentException exception)
+            {
-                Log.Error($"No application URL could be built for {_server.Url} due to {exception}");
+                Log.Error($"No application URL could be built for {_server.Url}.");
                 yield break;
+            }
-            HttpResponseMessage applicationsResponse;
             GotifyApplication[] gotifyApplications;
             try
             {
-                applicationsResponse = await _httpClient.GetAsync(applicationsUriBuilder.Uri, cancellationToken);
-            }
+                using var messageStream = await _httpClient.GetStreamAsync(combinedUri);
-            catch (Exception exception)
-            {
+                using var streamReader = new StreamReader(messageStream);
-                Log.Error($"Could not retrieve applications: {exception.Message}");
+                using var jsonTextReader = new JsonTextReader(streamReader);
-                yield break;
-            }
-            var applications = await applicationsResponse.Content.ReadAsStringAsync();
+                gotifyApplications = _jsonSerializer.Deserialize<GotifyApplication[]>(jsonTextReader);
-            GotifyApplication[] gotifyApplications;
+                if (gotifyApplications == null)
-            try
+                {
-                gotifyApplications =
+                    throw new ArgumentNullException();
                     JsonConvert.DeserializeObject<GotifyApplication[]>(applications);
             }
-            catch (JsonSerializationException exception)
+            catch (Exception exception)
+            {
-                Log.Warning($"Could not deserialize the list of applications from the server: {exception}");
+                Log.Warning(exception,"Could not deserialize the list of applications from the server.");
                 yield break;
+            }
             foreach (var application in gotifyApplications)
+            {
                 yield return application;
+            }
+        }
         private async Task<Stream> RetrieveGotifyApplicationImage(int appId, CancellationToken cancellationToken)
+        {
             await foreach (var application in RetrieveGotifyApplications(cancellationToken))
+            {
-                if (application.Id != appId) continue;
+                if (application.Id != appId)
+                {
+                    continue;
+                }
                 if (!Uri.TryCreate(Path.Combine($"{_httpUri}", $"{application.Image}"), UriKind.Absolute, out var applicationImageUri))
+                {
                     Log.Warning("Could not build URL path to application icon");
                     continue;
+                }
-                HttpResponseMessage imageResponse;
                 try
                 {
+                    var imageResponse = await _httpClient.GetAsync(applicationImageUri, cancellationToken);
+                    var memoryStream = new MemoryStream();
+                    await imageResponse.Content.CopyToAsync(memoryStream);
-                    imageResponse = await _httpClient.GetAsync(applicationImageUri, cancellationToken);
+                    return memoryStream;
+                }
                 catch (Exception exception)
+                {
                     Log.Error($"Could not retrieve application image: {exception.Message}");
-                    return new MemoryStream();
+                }
+            }
+            return new MemoryStream();
-                var memoryStream = new MemoryStream();
+        }
+        #endregion
+        private class GotifyConnectionApplication
+        {
+            public GotifyApplication Application { get; }
-                await imageResponse.Content.CopyToAsync(memoryStream);
+            public Server Server { get; }
             public GotifyConnectionApplication(Server server, GotifyApplication application)
-                memoryStream.Position = 0L;
                 return memoryStream;
+                Server = server;
+                Application = application;
+            }
+        }
+        private class GotifyConnectionData
-            }
+        {
+            public byte[] Payload { get; }
+            public Server Server { get; }
+            public GotifyConnectionData(byte[] payload, Server server)
+            {
-            return new MemoryStream();
+                Payload = payload;
                 Server = server;
+            }
         #endregion
+    }
+}
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