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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Usage of await operator in the JsonRpcMethod.","articleBody":"Hello. I was wondering if it is possible to use the await operator in `[JsonRpcMethod]` methods?\r\nInside the `[JsonRpcMethod]` I would like to call asynchronous methods and return `Task\u003cT\u003e` from the function. But this approach throws an exception. All I could do was call synchronous versions of the functions and return `Task.FromResult` from the  function.\r\n\r\nSome examples:\r\n\r\n```\r\nusing AustinHarris.JsonRpc;\r\n\r\nobject[] services = new object[] { new ExampleService() };\r\n\r\nfor (string line = Console.ReadLine(); !string.IsNullOrEmpty(line); line = Console.ReadLine())\r\n{\r\n    try\r\n    {\r\n        var response = await JsonRpcProcessor.Process(line);\r\n        Console.WriteLine(response);\r\n    }\r\n    catch(Exception ex)\r\n    {\r\n        Console.WriteLine(ex.ToString());\r\n    }\r\n\r\n}\r\npublic class ExampleService : JsonRpcService\r\n{\r\n    [JsonRpcMethod]\r\n    private async Task\u003cdouble\u003e DoSomethingAsync(double l, double r) // {'method':'DoSomethingAsync','params':[1.0,2.0],'id':1}\r\n    {\r\n        return await Worker.SummAsync(l, r);\r\n    }\r\n}\r\npublic class Worker\r\n{\r\n    public static async Task\u003cdouble\u003e SummAsync(double a, double b)\r\n    {\r\n        await Task.Delay(1000);\r\n        return await Task.FromResult(a + b);\r\n    }\r\n}\r\n```\r\nException:\r\n```\r\nNewtonsoft.Json.JsonSerializationException: Self referencing loop detected for property 'Task' with type 'System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[System.Double,ExampleService+\u003cDoSomethingAsync\u003ed__0]'. Path 'StateMachine.\u003c\u003et__builder'.\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.CheckForCircularReference(JsonWriter writer, Object value, JsonProperty property, JsonContract contract, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.CalculatePropertyValues(JsonWriter writer, Object value, JsonContainerContract contract, JsonProperty member, JsonProperty property, JsonContract\u0026 memberContract, Object\u0026 memberValue)\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType)\r\n   at Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value, Type objectType)\r\n   at Newtonsoft.Json.JsonSerializer.Serialize(JsonWriter jsonWriter, Object value, Type objectType)\r\n   at Newtonsoft.Json.JsonConvert.SerializeObjectInternal(Object value, Type type, JsonSerializer jsonSerializer)\r\n   at Newtonsoft.Json.JsonConvert.SerializeObject(Object value, Type type, JsonSerializerSettings settings)\r\n   at Newtonsoft.Json.JsonConvert.SerializeObject(Object value)\r\n   at AustinHarris.JsonRpc.JsonRpcProcessor.ProcessSync(String sessionId, String jsonRpc, Object jsonRpcContext, JsonSerializerSettings settings)\r\n   at AustinHarris.JsonRpc.JsonRpcProcessor.\u003c\u003ec.\u003cProcess\u003eb__3_0(Object _)\r\n   at System.Threading.Tasks.Task`1.InnerInvoke()\r\n   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)\r\n--- End of stack trace from previous location ---\r\n   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)\r\n   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task\u0026 currentTaskSlot, Thread threadPoolThread)\r\n--- End of stack trace from previous location ---\r\n   at Program.\u003cMain\u003e$(String[] args) in D:\\Work\\other\\JsonRpcNetAsync\\JsonRpcNetAsync\\Program.cs:line 9\r\n\r\n```\r\nWorking example:\r\n```\r\nusing AustinHarris.JsonRpc;\r\n\r\nobject[] services = new object[] { new ExampleService() };\r\n\r\nfor (string line = Console.ReadLine(); !string.IsNullOrEmpty(line); line = Console.ReadLine())\r\n{\r\n    try\r\n    {\r\n        Task\u003cstring\u003e task1 = JsonRpcProcessor.Process(line);\r\n        Task\u003cstring\u003e task2 = JsonRpcProcessor.Process(line);\r\n        Task\u003cstring\u003e task3 = JsonRpcProcessor.Process(line);\r\n        Task\u003cstring\u003e[] tasks = [task1, task2, task3];\r\n        string[] result = await Task.WhenAll(tasks);\r\n        foreach (string res in result) Console.WriteLine(res);\r\n    }\r\n    catch(Exception ex)\r\n    {\r\n        Console.WriteLine(ex.ToString());\r\n    }\r\n\r\n}\r\npublic class ExampleService : JsonRpcService\r\n{\r\n    [JsonRpcMethod]\r\n    private Task\u003cdouble\u003e DoSomethingAsync(double l, double r) // {'method':'DoSomethingAsync','params':[1.0,2.0],'id':1}\r\n    {\r\n        return Task.FromResult(Worker.SummSync(l, r));\r\n    }\r\n}\r\npublic class Worker\r\n{\r\n    public static double SummSync(double a, double b)\r\n    {\r\n        Thread.Sleep(10000);\r\n        return a + b;\r\n    }\r\n}\r\n```\r\nIf I understand correctly, calling `JsonRpcProcessor.Process(line)` runs in a separate thread, so blocking synchronous methods do not block the calling thread. But in the future, I might want to call asynchronous methods, and I was wondering if it is possible to do so using your framework? Thanks a lot for your answer!","author":{"url":"https://github.com/posahok","@type":"Person","name":"posahok"},"datePublished":"2024-09-17T16:31:53.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/147/JSON-RPC.NET/issues/147"}