add helper method.

src/DotNetCore.CAP/Infrastructure/Helper.cs

@@ -46,6 +46,7 @@ namespace DotNetCore.CAP.Infrastructure
             return (long)elapsedTime.TotalSeconds;
         }
 
+
         public static DateTime FromTimestamp(long value)
         {
             // ReSharper disable once ImpureMethodCallOnReadonlyValueField
@@ -72,24 +73,38 @@ namespace DotNetCore.CAP.Infrastructure
             return !CanConvertFromString(type);
         }
 
-		public static string AddJsonProperty(string json, IList<KeyValuePair<string, string>> properties)
+        public static JObject ToJObject(Exception exception)
         {
-			var jObj = JObject.Parse(json);
-			foreach (var property in properties)
+            return new JObject(new
             {
-				if (jObj.TryGetValue(property.Key, out var _))
+                Source = exception.Source,
+                Message = exception.Message,
+                InnerMessage = exception.InnerException?.Message
+            });
+        }
+
+        public static string AddJsonProperty(string json, string propertyName, JObject propertyValue)
         {
-					jObj[property.Key] = property.Value;
+            var jObj = JObject.Parse(json);
+
+            if (jObj.TryGetValue(propertyName, out var _))
+            {
+                jObj[propertyName] = propertyValue;
             }
             else
             {
-					jObj.Add(new JProperty(property.Key, property.Value));
-				}
+                jObj.Add(new JProperty(propertyName, propertyValue));
             }
 
             return jObj.ToString();
         }
 
+        public static string AddExceptionProperty(string json, Exception exception)
+        {
+            var jObject = ToJObject(exception);
+            return AddJsonProperty(json, "ExceptionMessage", jObject);
+        }
+
         private static bool CanConvertFromString(Type destinationType)
         {
             destinationType = Nullable.GetUnderlyingType(destinationType) ?? destinationType;