Remove dedicated values from contexts and only provide session items.

Source/MQTTnet.Server/Mqtt/MqttApplicationMessageInterceptor.cs

@@ -22,16 +22,13 @@ namespace MQTTnet.Server.Mqtt
         {
             try
             {
+                var sessionItems = (PythonDictionary)context.SessionItems[MqttServerConnectionValidator.WrappedSessionItemsKey];
+
                 var pythonContext = new PythonDictionary
                 {
                     { "client_id", context.ClientId },
+                    { "session_items", sessionItems },
                     { "retain", context.ApplicationMessage.Retain },
-                    { "username", context.Username },
-                    { "password", context.Password },
-                    { "raw_password", new Bytes(context.RawPassword ?? new byte[0]) },
-                    { "clean_session", context.CleanSession},
-                    { "authentication_method", context.AuthenticationMethod},
-                    { "authentication_data", new Bytes(context.AuthenticationData ?? new byte[0]) },
                     { "accept_publish", context.AcceptPublish },
                     { "close_connection", context.CloseConnection },
                     { "topic", context.ApplicationMessage.Topic },

Source/MQTTnet.Server/Mqtt/MqttServerConnectionValidator.cs

@@ -9,6 +9,8 @@ namespace MQTTnet.Server.Mqtt
 {
     public class MqttServerConnectionValidator : IMqttServerConnectionValidator
     {
+        public const string WrappedSessionItemsKey = "WRAPPED_ITEMS";
+
         private readonly PythonScriptHostService _pythonScriptHostService;
         private readonly ILogger _logger;
 
@@ -22,6 +24,8 @@ namespace MQTTnet.Server.Mqtt
         {
             try
             {
+                var sessionItems = new PythonDictionary();
+
                 var pythonContext = new PythonDictionary
                 {
                     { "endpoint", context.Endpoint },
@@ -33,6 +37,7 @@ namespace MQTTnet.Server.Mqtt
                     { "clean_session", context.CleanSession},
                     { "authentication_method", context.AuthenticationMethod},
                     { "authentication_data", new Bytes(context.AuthenticationData ?? new byte[0]) },
+                    { "session_items", sessionItems },
 
                     { "result", PythonConvert.Pythonfy(context.ReasonCode) }
                 };
@@ -40,6 +45,8 @@ namespace MQTTnet.Server.Mqtt
                 _pythonScriptHostService.InvokeOptionalFunction("on_validate_client_connection", pythonContext);
 
                 context.ReasonCode = PythonConvert.ParseEnum<MqttConnectReasonCode>((string)pythonContext["result"]);
+
+                context.SessionItems[WrappedSessionItemsKey] = sessionItems;
             }
             catch (Exception exception)
             {

Source/MQTTnet.Server/Mqtt/MqttSubscriptionInterceptor.cs

@@ -21,14 +21,16 @@ namespace MQTTnet.Server.Mqtt
         {
             try
             {
+                var sessionItems = (PythonDictionary)context.SessionItems[MqttServerConnectionValidator.WrappedSessionItemsKey];
+
                 var pythonContext = new PythonDictionary
                 {
-                    { "accept_subscription", context.AcceptSubscription },
-                    { "close_connection", context.CloseConnection },
-
                     { "client_id", context.ClientId },
+                    { "session_items", sessionItems },
                     { "topic", context.TopicFilter.Topic },
-                    { "qos", (int)context.TopicFilter.QualityOfServiceLevel }
+                    { "qos", (int)context.TopicFilter.QualityOfServiceLevel },
+                    { "accept_subscription", context.AcceptSubscription },
+                    { "close_connection", context.CloseConnection }
                 };
 
                 _pythonScriptHostService.InvokeOptionalFunction("on_intercept_subscription", pythonContext);

Source/MQTTnet/Server/MqttApplicationMessageInterceptorContext.cs

@@ -1,20 +1,25 @@
 using System.Collections.Generic;
-using MQTTnet.Packets;
 
 namespace MQTTnet.Server
 {
-    public class MqttApplicationMessageInterceptorContext : MqttBaseInterceptorContext
+    public class MqttApplicationMessageInterceptorContext
     {
-        public MqttApplicationMessageInterceptorContext(string clientId, IDictionary<object, object> sessionItems, MqttConnectPacket connectPacket, MqttApplicationMessage applicationMessage) : base(connectPacket, sessionItems)
+        public MqttApplicationMessageInterceptorContext(string clientId, IDictionary<object, object> sessionItems, MqttApplicationMessage applicationMessage)
         {
             ClientId = clientId;
             ApplicationMessage = applicationMessage;
+            SessionItems = sessionItems;
         }
 
         public string ClientId { get; }
 
         public MqttApplicationMessage ApplicationMessage { get; set; }
 
+        /// <summary>
+        /// Gets or sets a key/value collection that can be used to share data within the scope of this session.
+        /// </summary>
+        public IDictionary<object, object> SessionItems { get; }
+
         public bool AcceptPublish { get; set; } = true;
 
         public bool CloseConnection { get; set; }

Source/MQTTnet/Server/MqttBaseInterceptorContext.cs

@@ -1,54 +0,0 @@
-using System.Collections.Generic;
-using System.Text;
-using MQTTnet.Packets;
-
-namespace MQTTnet.Server
-{
-    public class MqttBaseInterceptorContext
-    {
-        private readonly MqttConnectPacket _connectPacket;
-
-        protected MqttBaseInterceptorContext(MqttConnectPacket connectPacket, IDictionary<object, object> sessionItems)
-        {
-            _connectPacket = connectPacket;
-            SessionItems = sessionItems;
-        }
-
-        public string Username => _connectPacket?.Username;
-
-        public byte[] RawPassword => _connectPacket?.Password;
-
-        public string Password => Encoding.UTF8.GetString(RawPassword ?? new byte[0]);
-
-        public MqttApplicationMessage WillMessage => _connectPacket?.WillMessage;
-
-        public bool? CleanSession => _connectPacket?.CleanSession;
-
-        public ushort? KeepAlivePeriod => _connectPacket?.KeepAlivePeriod;
-
-        public List<MqttUserProperty> UserProperties => _connectPacket?.Properties?.UserProperties;
-
-        public byte[] AuthenticationData => _connectPacket?.Properties?.AuthenticationData;
-
-        public string AuthenticationMethod => _connectPacket?.Properties?.AuthenticationMethod;
-
-        public uint? MaximumPacketSize => _connectPacket?.Properties?.MaximumPacketSize;
-
-        public ushort? ReceiveMaximum => _connectPacket?.Properties?.ReceiveMaximum;
-
-        public ushort? TopicAliasMaximum => _connectPacket?.Properties?.TopicAliasMaximum;
-
-        public bool? RequestProblemInformation => _connectPacket?.Properties?.RequestProblemInformation;
-
-        public bool? RequestResponseInformation => _connectPacket?.Properties?.RequestResponseInformation;
-
-        public uint? SessionExpiryInterval => _connectPacket?.Properties?.SessionExpiryInterval;
-
-        public uint? WillDelayInterval => _connectPacket?.Properties?.WillDelayInterval;
-
-        /// <summary>
-        /// Gets or sets a key/value collection that can be used to share data within the scope of this session.
-        /// </summary>
-        public IDictionary<object, object> SessionItems { get; }
-    }
-}

Source/MQTTnet/Server/MqttClientSession.cs

@@ -54,7 +54,7 @@ namespace MQTTnet.Server
 
         public async Task SubscribeAsync(ICollection<TopicFilter> topicFilters, MqttRetainedMessagesManager retainedMessagesManager)
         {
-            await SubscriptionsManager.SubscribeAsync(topicFilters, null).ConfigureAwait(false);
+            await SubscriptionsManager.SubscribeAsync(topicFilters).ConfigureAwait(false);
 
             var matchingRetainedMessages = await retainedMessagesManager.GetSubscribedMessagesAsync(topicFilters).ConfigureAwait(false);
             foreach (var matchingRetainedMessage in matchingRetainedMessages)

Source/MQTTnet/Server/MqttClientSessionsManager.cs

@@ -290,7 +290,7 @@ namespace MQTTnet.Server
 
         private async Task<MqttConnectionValidatorContext> ValidateConnectionAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter channelAdapter)
         {
-            var context = new MqttConnectionValidatorContext(connectPacket, channelAdapter);
+            var context = new MqttConnectionValidatorContext(connectPacket, channelAdapter, new ConcurrentDictionary<object, object>());
 
             var connectionValidator = _options.ConnectionValidator;
 
@@ -372,23 +372,20 @@ namespace MQTTnet.Server
 
             string senderClientId;
             IDictionary<object, object> sessionItems;
-            MqttConnectPacket connectPacket;
 
             var messageIsFromServer = senderConnection == null;
             if (messageIsFromServer)
             {
                 senderClientId = _options.ClientId;
                 sessionItems = _serverSessionItems;
-                connectPacket = null;
             }
             else
             {
                 senderClientId = senderConnection.ClientId;
                 sessionItems = senderConnection.Session.Items;
-                connectPacket = senderConnection.ConnectPacket;
             }
 
-            var interceptorContext = new MqttApplicationMessageInterceptorContext(senderClientId, sessionItems, connectPacket, applicationMessage);
+            var interceptorContext = new MqttApplicationMessageInterceptorContext(senderClientId, sessionItems, applicationMessage);
             await interceptor.InterceptApplicationMessagePublishAsync(interceptorContext).ConfigureAwait(false);
             return interceptorContext;
         }

Source/MQTTnet/Server/MqttClientSubscriptionsManager.cs

@@ -40,7 +40,7 @@ namespace MQTTnet.Server
 
             foreach (var originalTopicFilter in subscribePacket.TopicFilters)
             {
-                var interceptorContext = await InterceptSubscribeAsync(originalTopicFilter, connectPacket).ConfigureAwait(false);
+                var interceptorContext = await InterceptSubscribeAsync(originalTopicFilter).ConfigureAwait(false);
 
                 var finalTopicFilter = interceptorContext.TopicFilter;
 
@@ -74,13 +74,13 @@ namespace MQTTnet.Server
             return result;
         }
 
-        public async Task SubscribeAsync(IEnumerable<TopicFilter> topicFilters, MqttConnectPacket connectPacket)
+        public async Task SubscribeAsync(IEnumerable<TopicFilter> topicFilters)
         {
             if (topicFilters == null) throw new ArgumentNullException(nameof(topicFilters));
 
             foreach (var topicFilter in topicFilters)
             {
-                var interceptorContext = await InterceptSubscribeAsync(topicFilter, connectPacket).ConfigureAwait(false);
+                var interceptorContext = await InterceptSubscribeAsync(topicFilter).ConfigureAwait(false);
                 if (!interceptorContext.AcceptSubscription)
                 {
                    continue;
@@ -195,9 +195,9 @@ namespace MQTTnet.Server
             }
         }
 
-        private async Task<MqttSubscriptionInterceptorContext> InterceptSubscribeAsync(TopicFilter topicFilter, MqttConnectPacket connectPacket)
+        private async Task<MqttSubscriptionInterceptorContext> InterceptSubscribeAsync(TopicFilter topicFilter)
         {
-            var context = new MqttSubscriptionInterceptorContext(_clientSession.ClientId, topicFilter, connectPacket, _clientSession.Items);
+            var context = new MqttSubscriptionInterceptorContext(_clientSession.ClientId, topicFilter, _clientSession.Items);
             if (_serverOptions.SubscriptionInterceptor != null)
             {
                 await _serverOptions.SubscriptionInterceptor.InterceptSubscriptionAsync(context).ConfigureAwait(false);

Source/MQTTnet/Server/MqttConnectionValidatorContext.cs

@@ -1,7 +1,7 @@
 using System;
-using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Security.Cryptography.X509Certificates;
+using System.Text;
 using MQTTnet.Adapter;
 using MQTTnet.Formatter;
 using MQTTnet.Packets;
@@ -9,15 +9,16 @@ using MQTTnet.Protocol;
 
 namespace MQTTnet.Server
 {
-    public class MqttConnectionValidatorContext : MqttBaseInterceptorContext
+    public class MqttConnectionValidatorContext
     {
         private readonly MqttConnectPacket _connectPacket;
         private readonly IMqttChannelAdapter _clientAdapter;
 
-        public MqttConnectionValidatorContext(MqttConnectPacket connectPacket, IMqttChannelAdapter clientAdapter) : base(connectPacket, new ConcurrentDictionary<object, object>())
+        public MqttConnectionValidatorContext(MqttConnectPacket connectPacket, IMqttChannelAdapter clientAdapter, IDictionary<object, object> sessionItems)
         {
             _connectPacket = connectPacket;
             _clientAdapter = clientAdapter ?? throw new ArgumentNullException(nameof(clientAdapter));
+            SessionItems = sessionItems;
         }
 
         public string ClientId => _connectPacket.ClientId;
@@ -29,7 +30,44 @@ namespace MQTTnet.Server
         public X509Certificate2 ClientCertificate => _clientAdapter.ClientCertificate;
 
         public MqttProtocolVersion ProtocolVersion => _clientAdapter.PacketFormatterAdapter.ProtocolVersion;
-        
+
+        public string Username => _connectPacket?.Username;
+
+        public byte[] RawPassword => _connectPacket?.Password;
+
+        public string Password => Encoding.UTF8.GetString(RawPassword ?? new byte[0]);
+
+        public MqttApplicationMessage WillMessage => _connectPacket?.WillMessage;
+
+        public bool? CleanSession => _connectPacket?.CleanSession;
+
+        public ushort? KeepAlivePeriod => _connectPacket?.KeepAlivePeriod;
+
+        public List<MqttUserProperty> UserProperties => _connectPacket?.Properties?.UserProperties;
+
+        public byte[] AuthenticationData => _connectPacket?.Properties?.AuthenticationData;
+
+        public string AuthenticationMethod => _connectPacket?.Properties?.AuthenticationMethod;
+
+        public uint? MaximumPacketSize => _connectPacket?.Properties?.MaximumPacketSize;
+
+        public ushort? ReceiveMaximum => _connectPacket?.Properties?.ReceiveMaximum;
+
+        public ushort? TopicAliasMaximum => _connectPacket?.Properties?.TopicAliasMaximum;
+
+        public bool? RequestProblemInformation => _connectPacket?.Properties?.RequestProblemInformation;
+
+        public bool? RequestResponseInformation => _connectPacket?.Properties?.RequestResponseInformation;
+
+        public uint? SessionExpiryInterval => _connectPacket?.Properties?.SessionExpiryInterval;
+
+        public uint? WillDelayInterval => _connectPacket?.Properties?.WillDelayInterval;
+
+        /// <summary>
+        /// Gets or sets a key/value collection that can be used to share data within the scope of this session.
+        /// </summary>
+        public IDictionary<object, object> SessionItems { get; }
+
         /// <summary>
         /// This is used for MQTTv3 only.
         /// </summary>

Source/MQTTnet/Server/MqttSubscriptionInterceptorContext.cs

@@ -1,21 +1,25 @@
-using System;
+using System.Collections.Generic;
-using System.Collections.Generic;
-using MQTTnet.Packets;
 
 namespace MQTTnet.Server
 {
-    public class MqttSubscriptionInterceptorContext : MqttBaseInterceptorContext
+    public class MqttSubscriptionInterceptorContext
     {
-        public MqttSubscriptionInterceptorContext(string clientId, TopicFilter topicFilter, MqttConnectPacket connectPacket, IDictionary<object, object> sessionItems) : base(connectPacket, sessionItems)
+        public MqttSubscriptionInterceptorContext(string clientId, TopicFilter topicFilter, IDictionary<object, object> sessionItems)
         {
             ClientId = clientId;
-            TopicFilter = topicFilter ?? throw new ArgumentNullException(nameof(topicFilter));
+            TopicFilter = topicFilter;
+            SessionItems = sessionItems;
         }
 
         public string ClientId { get; }
 
         public TopicFilter TopicFilter { get; set; }
 
+        /// <summary>
+        /// Gets or sets a key/value collection that can be used to share data within the scope of this session.
+        /// </summary>
+        public IDictionary<object, object> SessionItems { get; }
+
         public bool AcceptSubscription { get; set; } = true;
 
         public bool CloseConnection { get; set; }

Tests/MQTTnet.Core.Tests/Session_Tests.cs

@@ -0,0 +1,61 @@
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using MQTTnet.Client;
+using MQTTnet.Client.Subscribing;
+using MQTTnet.Server;
+using MQTTnet.Tests.Mockups;
+
+namespace MQTTnet.Tests
+{
+    [TestClass]
+    public class Session_Tests
+    {
+        [TestMethod]
+        public async Task Set_Session_Item()
+        {
+            using (var testEnvironment = new TestEnvironment())
+            {
+                var serverOptions = new MqttServerOptionsBuilder()
+                    .WithConnectionValidator(delegate (MqttConnectionValidatorContext context)
+                    {
+                        // Don't validate anything. Just set some session items.
+                        context.SessionItems["can_subscribe_x"] = true;
+                        context.SessionItems["default_payload"] = "Hello World";
+                    })
+                    .WithSubscriptionInterceptor(delegate (MqttSubscriptionInterceptorContext context)
+                    {
+                        if (context.TopicFilter.Topic == "x")
+                        {
+                            context.AcceptSubscription = context.SessionItems["can_subscribe_x"] as bool? == true;
+                        }
+                    })
+                    .WithApplicationMessageInterceptor(delegate (MqttApplicationMessageInterceptorContext context)
+                    {
+                        context.ApplicationMessage.Payload = Encoding.UTF8.GetBytes(context.SessionItems["default_payload"] as string);
+                    });
+
+                await testEnvironment.StartServerAsync(serverOptions);
+
+                string receivedPayload = null;
+
+                var client = await testEnvironment.ConnectClientAsync();
+                client.UseApplicationMessageReceivedHandler(delegate(MqttApplicationMessageReceivedEventArgs args)
+                {
+                    receivedPayload = args.ApplicationMessage.ConvertPayloadToString();
+                });
+
+                var subscribeResult = await client.SubscribeAsync("x");
+
+                Assert.AreEqual(MqttClientSubscribeResultCode.GrantedQoS0, subscribeResult.Items[0].ResultCode);
+
+                var client2 = await testEnvironment.ConnectClientAsync();
+                await client2.PublishAsync("x");
+
+                await Task.Delay(1000);
+
+                Assert.AreEqual("Hello World", receivedPayload);
+            }
+        }
+    }
+}