feature flags (#130)

Signed-off-by: Gabriele Santomaggio <[email protected]>

Author: Gsantomaggio

RabbitMQ.AMQP.Client/FeatureFlags.cs

@@ -0,0 +1,21 @@
+// This source code is dual-licensed under the Apache License, version 2.0,
+// and the Mozilla Public License, version 2.0.
+// Copyright (c) 2017-2024 Broadcom. All Rights Reserved. The term "Broadcom" refers to Broadcom Inc. and/or its subsidiaries.
+
+namespace RabbitMQ.AMQP.Client
+{
+    internal class FeatureFlags
+    {
+        public bool IsSqlFeatureEnabled { get; set; } = false;
+        public bool IsBrokerCompatible { get; set; } = false;
+
+        public void Validate()
+        {
+            if (!IsBrokerCompatible)
+            {
+                throw new ConnectionException("Client not compatible with the broker version. " +
+                                              "The client requires RabbitMQ 4.0 or later.");
+            }
+        }
+    }
+}

RabbitMQ.AMQP.Client/Impl/AmqpConnection.cs

@@ -40,6 +40,7 @@ public class AmqpConnection : AbstractLifeCycle, IConnection
 
         private readonly Dictionary<string, object> _connectionProperties = new();
         private bool _areFilterExpressionsSupported = false;
+        private FeatureFlags _featureFlags = new FeatureFlags();
 
         /// <summary>
         /// _publishersDict contains all the publishers created by the connection.
@@ -90,6 +91,7 @@ public static async Task<IConnection> CreateAsync(ConnectionSettings connectionS
             AmqpConnection connection = new(connectionSettings, metricsReporter);
             await connection.OpenAsync()
                 .ConfigureAwait(false);
+
             return connection;
         }
 
@@ -189,6 +191,7 @@ await OpenConnectionAsync(CancellationToken.None)
                 .ConfigureAwait(false);
             await base.OpenAsync()
                 .ConfigureAwait(false);
+            _featureFlags.Validate();
         }
 
         public override async Task CloseAsync()
@@ -665,10 +668,11 @@ private void HandleProperties(Fields properties)
             }
 
             string brokerVersion = (string)_connectionProperties["version"];
-            if (false == Utils.Is4_0_OrMore(brokerVersion))
-            {
-                // TODO Java client throws exception here
-            }
+            _featureFlags.IsBrokerCompatible = Utils.Is4_0_OrMore(brokerVersion);
+
+            // check if the broker supports filter expressions
+            // this is a feature that was introduced in RabbitMQ 4.2.0
+            _featureFlags.IsSqlFeatureEnabled = Utils.Is4_2_OrMore(brokerVersion);
 
             _areFilterExpressionsSupported = Utils.SupportsFilterExpressions(brokerVersion);
         }

RabbitMQ.AMQP.Client/Utils.cs

@@ -250,6 +250,11 @@ internal static bool Is4_1_OrMore(string brokerVersion)
             return VersionCompare(CurrentVersion(brokerVersion), "4.1.0") >= 0;
         }
 
+        internal static bool Is4_2_OrMore(string brokerVersion)
+        {
+            return VersionCompare(CurrentVersion(brokerVersion), "4.2.0") >= 0;
+        }
+
         private static string CurrentVersion(string currentVersion)
         {
             // versions built from source: 3.7.0+rc.1.4.gedc5d96