Add support for retained application messages

2026-10-16 17:23:04 +08:00 · 2017-09-30 18:42:41 +02:00
parent 3cce33415d
commit 862f76fea2
24 changed files with 454 additions and 235 deletions
@@ -0,0 +1,90 @@
+using System;
+using System.Collections.Concurrent;
+using System.Threading;
+using System.Threading.Tasks;
+using MQTTnet.Core.Adapter;
+using MQTTnet.Core.Diagnostics;
+using MQTTnet.Core.Exceptions;
+using MQTTnet.Core.Packets;
+using MQTTnet.Core.Protocol;
+
+namespace MQTTnet.Core.Server
+{
+    public sealed class MqttClientPendingMessagesQueue
+    {
+        private readonly BlockingCollection<MqttPublishPacket> _pendingPublishPackets = new BlockingCollection<MqttPublishPacket>();
+        private readonly MqttClientSession _session;
+        private readonly MqttServerOptions _options;
+
+        public MqttClientPendingMessagesQueue(MqttServerOptions options, MqttClientSession session)
+        {
+            _session = session ?? throw new ArgumentNullException(nameof(session));
+            _options = options ?? throw new ArgumentNullException(nameof(options));
+        }
+
+        public void Start(IMqttCommunicationAdapter adapter, CancellationToken cancellationToken)
+        {
+            if (adapter == null) throw new ArgumentNullException(nameof(adapter));
+
+            Task.Run(() => SendPendingPublishPacketsAsync(adapter, cancellationToken), cancellationToken);
+        }
+
+        public void Enqueue(MqttPublishPacket publishPacket)
+        {
+            if (publishPacket == null) throw new ArgumentNullException(nameof(publishPacket));
+
+            _pendingPublishPackets.Add(publishPacket);
+        }
+
+        private async Task SendPendingPublishPacketsAsync(IMqttCommunicationAdapter adapter, CancellationToken cancellationToken)
+        {
+            try
+            {
+                while (!cancellationToken.IsCancellationRequested)
+                {
+                    await SendPendingPublishPacketAsync(adapter, cancellationToken);
+                }
+            }
+            catch (OperationCanceledException)
+            {
+            }
+            catch (Exception exception)
+            {
+                MqttTrace.Error(nameof(MqttClientPendingMessagesQueue), exception, "Unhandled exception while sending pending publish packets.");
+            }
+        }
+
+        private async Task SendPendingPublishPacketAsync(IMqttCommunicationAdapter adapter, CancellationToken cancellationToken)
+        {
+            var packet = _pendingPublishPackets.Take(cancellationToken);
+
+            try
+            {
+                await adapter.SendPacketsAsync(_options.DefaultCommunicationTimeout, cancellationToken, packet).ConfigureAwait(false);
+            }
+            catch (Exception exception)
+            {
+                if (exception is MqttCommunicationTimedOutException)
+                {
+                    MqttTrace.Warning(nameof(MqttClientPendingMessagesQueue), exception, "Sending publish packet failed due to timeout.");
+                }
+                else if (exception is MqttCommunicationException)
+                {
+                    MqttTrace.Warning(nameof(MqttClientPendingMessagesQueue), exception, "Sending publish packet failed due to communication exception.");
+                }
+                else
+                {
+                    MqttTrace.Error(nameof(MqttClientPendingMessagesQueue), exception, "Sending publish packet failed.");
+                }
+
+                if (packet.QualityOfServiceLevel > MqttQualityOfServiceLevel.AtMostOnce)
+                {
+                    packet.Dup = true;
+                    _pendingPublishPackets.Add(packet, cancellationToken);
+                }
+
+                _session.Stop();
+            }
+        }
+    }
+}