Listening imap inbox changes with idle client.

Wino.Core/Services/LogInitializer.cs

@@ -26,7 +26,7 @@ namespace Wino.Core.Services
         {
             Log.Logger = new LoggerConfiguration()
                         .MinimumLevel.ControlledBy(_levelSwitch)
-                        .WriteTo.File(fullLogFilePath, retainedFileCountLimit: 3, rollOnFileSizeLimit: true, rollingInterval: RollingInterval.Day)
+                        .WriteTo.File(fullLogFilePath, retainedFileCountLimit: 2, rollOnFileSizeLimit: true, rollingInterval: RollingInterval.Day)
                         .WriteTo.Debug()
                         .Enrich.FromLogContext()
                         .Enrich.WithExceptionDetails()

Wino.Core/Synchronizers/ImapSynchronizer.cs

@@ -1,8 +1,10 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+using CommunityToolkit.Mvvm.Messaging;
 using MailKit;
 using MailKit.Net.Imap;
 using MailKit.Search;
@@ -21,13 +23,14 @@ using Wino.Core.Integration.Processors;
 using Wino.Core.Mime;
 using Wino.Core.Requests;
 using Wino.Core.Requests.Bundles;
+using Wino.Messaging.Server;
 
 namespace Wino.Core.Synchronizers
 {
     public class ImapSynchronizer : BaseSynchronizer<ImapRequest, ImapMessageCreationPackage>
     {
         private CancellationTokenSource idleDoneToken;
-        private CancellationTokenSource cancelInboxListeningToken = new CancellationTokenSource();
+        private CancellationTokenSource cancelInboxListeningToken;
 
         private IMailFolder inboxFolder;
 
@@ -35,6 +38,8 @@ namespace Wino.Core.Synchronizers
         private readonly ImapClientPool _clientPool;
         private readonly IImapChangeProcessor _imapChangeProcessor;
 
+        public bool IsChangeListeningActive { get; set; }
+
         // Minimum summary items to Fetch for mail synchronization from IMAP.
         private readonly MessageSummaryItems mailSynchronizationFlags =
             MessageSummaryItems.Flags |
@@ -47,12 +52,6 @@ namespace Wino.Core.Synchronizers
             MessageSummaryItems.References |
             MessageSummaryItems.ModSeq;
 
-        /// <summary>
-        /// Timer that keeps the <see cref="InboxClient"/> alive for the lifetime of the pool.
-        /// Sends NOOP command to the server periodically.
-        /// </summary>
-        private Timer _noOpTimer;
-
         /// <summary>
         /// ImapClient that keeps the Inbox folder opened all the time for listening notifications.
         /// </summary>
@@ -65,44 +64,69 @@ namespace Wino.Core.Synchronizers
         {
             _clientPool = new ImapClientPool(Account.ServerInformation);
             _imapChangeProcessor = imapChangeProcessor;
-
-            idleDoneToken = new CancellationTokenSource();
         }
 
-        // TODO
-        // private async void NoOpTimerTriggered(object state) => await AwaitInboxIdleAsync();
-
         private async Task AwaitInboxIdleAsync()
         {
             if (_inboxIdleClient == null)
             {
-                _logger.Warning("InboxClient is null. Cannot send NOOP command.");
+                _logger.Warning("InboxClient is null. Cannot send IDLE command.");
                 return;
             }
 
+            if (inboxFolder == null)
+            {
+                _logger.Warning("Inbox folder is null. Cannot listen for changes.");
+                return;
+            }
+
+            idleDoneToken ??= new CancellationTokenSource();
+            cancelInboxListeningToken ??= new CancellationTokenSource();
+
             await _clientPool.EnsureConnectedAsync(_inboxIdleClient);
             await _clientPool.EnsureAuthenticatedAsync(_inboxIdleClient);
 
             try
             {
-                if (inboxFolder == null)
+                if (!inboxFolder.IsOpen)
                 {
-                    inboxFolder = _inboxIdleClient.Inbox;
                     await inboxFolder.OpenAsync(FolderAccess.ReadOnly, cancelInboxListeningToken.Token);
                 }
 
-                idleDoneToken = new CancellationTokenSource();
+                if (!_inboxIdleClient.IsIdle)
+                {
+                    idleDoneToken = new CancellationTokenSource();
 
-                await _inboxIdleClient.IdleAsync(idleDoneToken.Token, cancelInboxListeningToken.Token);
+                    IsChangeListeningActive = true;
+
+                    await _inboxIdleClient.IdleAsync(idleDoneToken.Token, cancelInboxListeningToken.Token);
+                }
+            }
+            catch (ImapProtocolException)
+            {
+                await ReconnectAsync();
+            }
+            catch (IOException)
+            {
+                await ReconnectAsync();
+            }
+            catch (Exception exception)
+            {
+                Logger.Error(exception, "Error occured while listening for Inbox changes.");
             }
             finally
             {
-                idleDoneToken.Dispose();
-                idleDoneToken = null;
+                IsChangeListeningActive = false;
             }
         }
 
-        private async Task StopInboxListeningAsync()
+        private async Task ReconnectAsync()
+        {
+            await _clientPool.EnsureConnectedAsync(_inboxIdleClient);
+            await _clientPool.EnsureAuthenticatedAsync(_inboxIdleClient);
+        }
+
+        public async Task StopInboxListeningAsync()
         {
             if (inboxFolder != null)
             {
@@ -111,12 +135,6 @@ namespace Wino.Core.Synchronizers
                 inboxFolder.MessageFlagsChanged -= InboxFolderMessageFlagsChanged;
             }
 
-            if (_noOpTimer != null)
-            {
-                _noOpTimer.Dispose();
-                _noOpTimer = null;
-            }
-
             if (idleDoneToken != null)
             {
                 idleDoneToken.Cancel();
@@ -124,9 +142,19 @@ namespace Wino.Core.Synchronizers
                 idleDoneToken = null;
             }
 
+            if (cancelInboxListeningToken != null)
+            {
+                cancelInboxListeningToken.Cancel();
+                cancelInboxListeningToken.Dispose();
+                cancelInboxListeningToken = null;
+            }
+
+            IsChangeListeningActive = false;
+
             if (_inboxIdleClient != null)
             {
                 await _inboxIdleClient.DisconnectAsync(true);
+
                 _inboxIdleClient.Dispose();
                 _inboxIdleClient = null;
             }
@@ -136,20 +164,14 @@ namespace Wino.Core.Synchronizers
         /// Tries to connect & authenticate with the given credentials.
         /// Prepares synchronizer for active listening of Inbox folder.
         /// </summary>
-        public async Task StartInboxListeningAsync()
+        public async Task<bool> StartInboxListeningAsync()
         {
             _inboxIdleClient = await _clientPool.GetClientAsync();
 
-            // Run it every 8 minutes after 1 minute delay.
-            // _noOpTimer = new Timer(NoOpTimerTriggered, null, 60000, 8 * 60 * 1000);
-
-            await _clientPool.EnsureConnectedAsync(_inboxIdleClient);
-            await _clientPool.EnsureAuthenticatedAsync(_inboxIdleClient);
-
             if (!_inboxIdleClient.Capabilities.HasFlag(ImapCapabilities.Idle))
             {
                 _logger.Information("Imap server does not support IDLE command. Listening live changes is not supported for {Name}", Account.Name);
-                return;
+                return false;
             }
 
             inboxFolder = _inboxIdleClient.Inbox;
@@ -157,35 +179,62 @@ namespace Wino.Core.Synchronizers
             if (inboxFolder == null)
             {
                 _logger.Information("Inbox folder is null. Cannot listen for changes.");
-                return;
+
+                return false;
             }
 
             inboxFolder.CountChanged += InboxFolderCountChanged;
             inboxFolder.MessageExpunged += InboxFolderMessageExpunged;
             inboxFolder.MessageFlagsChanged += InboxFolderMessageFlagsChanged;
 
-            while (!cancelInboxListeningToken.IsCancellationRequested)
+            try
             {
-                await AwaitInboxIdleAsync();
+                while (true)
+                {
+                    await AwaitInboxIdleAsync();
+                }
+            }
+            catch (OperationCanceledException)
+            {
+                Log.Information("Listening Inbox changes for IMAP is canceled.");
+            }
+            catch (Exception ex)
+            {
+                Log.Error(ex, "Error occured while listening for Inbox changes.");
+                return false;
             }
 
-            await StopInboxListeningAsync();
+            return true;
+        }
+
+        /// <summary>
+        /// When a change occurs in the Inbox folder, this method is called to force synchronization.
+        /// Quueing new sync is ignored if the synchronizer is already in a synchronization process.
+        /// </summary>
+        private void ForceInboxIdleSynchronization()
+        {
+            // Do not try to synchronize if we're already in a synchronization process.
+
+            if (State == AccountSynchronizerState.Idle)
+            {
+                var options = new SynchronizationOptions()
+                {
+                    Type = SynchronizationType.Inbox,
+                    AccountId = Account.Id
+                };
+
+                WeakReferenceMessenger.Default.Send(new NewSynchronizationRequested(options, SynchronizationSource.Server));
+            }
         }
 
         private void InboxFolderMessageFlagsChanged(object sender, MessageFlagsChangedEventArgs e)
-        {
-            Console.WriteLine("Flags have changed for message #{0} ({1}).", e.Index, e.Flags);
-        }
+            => ForceInboxIdleSynchronization();
 
         private void InboxFolderMessageExpunged(object sender, MessageEventArgs e)
-        {
-            _logger.Information("Inbox folder message expunged");
-        }
+            => ForceInboxIdleSynchronization();
 
         private void InboxFolderCountChanged(object sender, EventArgs e)
-        {
-            _logger.Information("Inbox folder count changed.");
-        }
+            => ForceInboxIdleSynchronization();
 
         /// <summary>
         /// Parses List of string of mail copy ids and return valid uIds.
@@ -998,5 +1047,21 @@ namespace Wino.Core.Synchronizers
         /// <param name="remoteFolder">Remote folder</param>
         /// <param name="localFolder">Local folder.</param>
         public bool ShouldUpdateFolder(IMailFolder remoteFolder, MailItemFolder localFolder) => remoteFolder.Name != localFolder.FolderName;
+
+        /// <summary>
+        /// 1. Stops active inbox listening.
+        /// 2. Disconnects client pool with all clients.
+        /// 3. Disposes everything gracefully.
+        ///
+        /// Usefull for killing server scenario where nothing is needed to be connected to IMAP server anymore.
+        /// </summary>
+        public async Task KillAsync()
+        {
+            Log.Debug("Killing ImapSynchronizer for {Name}", Account.Name);
+
+            await StopInboxListeningAsync();
+
+            _clientPool.Dispose();
+        }
     }
 }

Wino.Messages/Server/NewSynchronizationRequested.cs

@@ -8,5 +8,5 @@ namespace Wino.Messaging.Server
     /// Triggers a new synchronization if possible.
     /// </summary>
     /// <param name="Options">Options for synchronization.</param>
-    public record NewSynchronizationRequested(SynchronizationOptions Options, SynchronizationSource Source) : IClientMessage;
+    public record NewSynchronizationRequested(SynchronizationOptions Options, SynchronizationSource Source) : IClientMessage, IUIMessage;
 }

Wino.Server/ServerContext.cs

@@ -13,6 +13,7 @@ using Wino.Core.Domain.Models.Requests;
 using Wino.Core.Domain.Models.Synchronization;
 using Wino.Core.Integration.Json;
 using Wino.Core.Services;
+using Wino.Core.Synchronizers;
 using Wino.Messaging;
 using Wino.Messaging.Client.Authorization;
 using Wino.Messaging.Enums;
@@ -40,7 +41,8 @@ namespace Wino.Server
         IRecipient<AccountSynchronizerStateChanged>,
         IRecipient<RefreshUnreadCountsMessage>,
         IRecipient<ServerTerminationModeChanged>,
-        IRecipient<AccountSynchronizationProgressUpdatedMessage>
+        IRecipient<AccountSynchronizationProgressUpdatedMessage>,
+        IRecipient<NewSynchronizationRequested>
     {
         private readonly System.Timers.Timer _timer;
         private static object connectionLock = new object();
@@ -57,6 +59,8 @@ namespace Wino.Server
             TypeInfoResolver = new ServerRequestTypeInfoResolver()
         };
 
+        private Task imapIdleTask = null;
+
         public ServerContext(IDatabaseService databaseService,
                              IApplicationConfiguration applicationFolderConfiguration,
                              ISynchronizerFactory synchronizerFactory,
@@ -171,7 +175,11 @@ namespace Wino.Server
 
             AppServiceConnectionStatus status = await connection.OpenAsync();
 
-            if (status != AppServiceConnectionStatus.Success)
+            if (status == AppServiceConnectionStatus.Success)
+            {
+                imapIdleTask = RegisterImapSynchronizerChangesAsync();
+            }
+            else
             {
                 Log.Error("Opening server connection failed. Status: {status}", status);
 
@@ -179,6 +187,53 @@ namespace Wino.Server
             }
         }
 
+        private async Task PerformForAllImapSynchronizers(Action<ImapSynchronizer> action)
+        {
+            var allAccounts = await _accountService.GetAccountsAsync().ConfigureAwait(false);
+
+            var imapAccounts = allAccounts.FindAll(a => a.ProviderType == MailProviderType.IMAP4);
+
+            foreach (var account in imapAccounts)
+            {
+                var synchronizer = await _synchronizerFactory.GetAccountSynchronizerAsync(account.Id).ConfigureAwait(false);
+
+                if (synchronizer == null) continue;
+                if (synchronizer is not ImapSynchronizer accountImapSynchronizer)
+                {
+                    Log.Warning("Account '{Name}' has IMAP4 type but synchronizer is not ImapSynchronizer.", account.Name);
+                    continue;
+                }
+
+                action(accountImapSynchronizer);
+            }
+        }
+
+        /// <summary>
+        /// Hooks all ImapSynchronizer instances to listen for changes like new mail, folder rename etc.
+        /// </summary>
+        private Task RegisterImapSynchronizerChangesAsync()
+            => PerformForAllImapSynchronizers(async accountImapSynchronizer =>
+            {
+                // First make sure that listening is stopped.
+
+                await accountImapSynchronizer.StopInboxListeningAsync();
+
+                var startListeningTask = accountImapSynchronizer.StartInboxListeningAsync();
+
+                await Task.Delay(10000); // Wait for 10 seconds.
+
+                if (startListeningTask.Exception == null)
+                {
+                    Log.Information("IMAP change listening started for account '{Name}'.", accountImapSynchronizer.Account.Name);
+                }
+            });
+
+        public Task DisposeActiveImapConnectionsAsync()
+            => PerformForAllImapSynchronizers(async accountImapSynchronizer =>
+            {
+                await accountImapSynchronizer.KillAsync();
+            });
+
         /// <summary>
         /// Disposes current connection to UWP app service.
         /// </summary>
@@ -337,5 +392,10 @@ namespace Wino.Server
 
             App.Current.ChangeNotifyIconVisiblity(isServerTrayIconVisible);
         }
+
+        public async void Receive(NewSynchronizationRequested message)
+        {
+            await ExecuteServerMessageSafeAsync(null, message);
+        }
     }
 }

Wino.Server/ServerViewModel.cs

@@ -26,6 +26,8 @@ namespace Wino.Server
         [RelayCommand]
         public Task LaunchWinoAsync()
         {
+            // Stop listening active imap synchronizer changes and disconnect gracefully.
+            return Context.DisposeActiveImapConnectionsAsync();
             //var opt = new SynchronizationOptions()
             //{
             //    Type = Wino.Core.Domain.Enums.SynchronizationType.Full,
@@ -37,7 +39,7 @@ namespace Wino.Server
 
             // return Task.CompletedTask;
 
-            return Launcher.LaunchUriAsync(new Uri($"{App.WinoMailLaunchProtocol}:")).AsTask();
+            // return Launcher.LaunchUriAsync(new Uri($"{App.WinoMailLaunchProtocol}:")).AsTask();
             //await _notificationBuilder.CreateNotificationsAsync(Guid.Empty, new List<IMailItem>()
             //{
             //    new MailCopy(){  UniqueId = Guid.Parse("8f25d2a0-4448-4fee-96a9-c9b25a19e866")}
@@ -71,6 +73,9 @@ namespace Wino.Server
                 }
             }
 
+            // Stop listening active imap synchronizer changes and disconnect gracefully.
+            await Context.DisposeActiveImapConnectionsAsync();
+
             Application.Current.Shutdown();
         }