modify prompted info when received message can not be found subscriber. #63

src/DotNetCore.CAP/Internal/ISubscriberExecutor.Default.cs

 using System;
+using System.Linq;
 using System.Threading.Tasks;
 using DotNetCore.CAP.Abstractions;
 using DotNetCore.CAP.Models;
@@ -28,22 +29,18 @@ namespace DotNetCore.CAP.Internal
 
         public async Task<OperateResult> ExecuteAsync(CapReceivedMessage receivedMessage)
         {
-            try
+            if (!_selector.TryGetTopicExector(receivedMessage.Name, receivedMessage.Group,
+                out var executor))
             {
-                var executeDescriptorGroup = _selector.GetTopicExector(receivedMessage.Name);
-
-                if (!executeDescriptorGroup.ContainsKey(receivedMessage.Group))
-                {
-                    var error = $"Topic:{receivedMessage.Name}, can not be found subscriber method.";
-                    throw new SubscriberNotFoundException(error);
-                }
-
-                // If there are multiple consumers in the same group, we will take the first
-                var executeDescriptor = executeDescriptorGroup[receivedMessage.Group][0];
-                var consumerContext = new ConsumerContext(executeDescriptor, receivedMessage.ToMessageContext());
+                var error = "this message can not be found subscriber. Message:" + receivedMessage;
+                error += "\r\n  see: https://github.com/dotnetcore/CAP/issues/63";
+                throw new SubscriberNotFoundException(error);
+            }
 
+            var consumerContext = new ConsumerContext(executor, receivedMessage.ToMessageContext());
+            try
+            {
                 var ret = await Invoker.InvokeAsync(consumerContext);
-
                 if (!string.IsNullOrEmpty(ret.CallbackName))
                     await _callbackMessageSender.SendAsync(ret.MessageId, ret.CallbackName, ret.Result);
 

src/DotNetCore.CAP/Internal/MethodMatcherCache.cs

@@ -55,6 +55,29 @@ namespace DotNetCore.CAP.Internal
             return dic;
         }
 
+        /// <summary>
+        /// Attempts to get the topic exector associated with the specified topic name and group name from the <see cref="Entries"/>.
+        /// </summary>
+        /// <param name="topicName">The topic name of the value to get.</param>
+        /// <param name="groupName">The group name of the value to get.</param>
+        /// <param name="matchTopic">topic exector of the value.</param>
+        /// <returns>true if the key was found, otherwise false. </returns>
+        public bool TryGetTopicExector(string topicName, string groupName,
+            out ConsumerExecutorDescriptor matchTopic)
+        {
+            if (Entries == null)
+                throw new ArgumentNullException(nameof(Entries));
+
+            matchTopic = null;
+
+            if (Entries.TryGetValue(groupName, out var groupMatchTopics))
+            {
+                matchTopic = groupMatchTopics.FirstOrDefault(x => x.Attribute.Name == topicName);
+                return matchTopic != null;
+            }
+            return false;
+        }
+
         /// <summary>
         /// Get all subscribe topics name.
         /// </summary>

src/DotNetCore.CAP/Models/CapReceivedMessage.cs

@@ -47,7 +47,7 @@ namespace DotNetCore.CAP.Models
 
         public override string ToString()
         {
-            return "name:" + Name + ", content:" + Content;
+            return "name:" + Name + ", group:" + Group + ", content:" + Content;
         }
     }
 }
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