Serializing an Exception Return a Very Large JSON

Question

I'm migrating an application from full framework to net core. I'm struggling to get the exception manager for the apis to get to work.

I'm currently using a attribute based solution.

I have this class

public class ApiExceptionFilterAttribute : ExceptionFilterAttribute
{
    public override async void OnException(ExceptionContext context)
    {
        context.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
        var ex = context.Exception;
        if (ex == null) return;

        context.HttpContext.Response.ContentType = "application/json";

        using (var writer = new StreamWriter(context.HttpContext.Response.Body))
        {
            var js = new JsonSerializer();
            js.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
            js.Serialize(writer, ex);
            await writer.FlushAsync().ConfigureAwait(false);
        }
    }
}

and I use the corresponding attribute on the desired controller. [ApiExceptionFilter]

The thing is, that when I catch the exception and throw it to the client as a JSON string. I got a 27mb download, and its because it's serializing the TargetSite and within of that it serialize the DefinedTypes which is a list of assemblies and types.

Does somebody know how can I serialize the exception avoiding those properties?

Here is an example of the exception:

{
Id: null,
Message: "Hubo errores en la validación de los parámetros de la operación.",
Data: { },
InnerException: {
Detail: {
Details: [
{
Key: "Cuit",
Message: "The field Cuit must match the regular expression '^[0-9]{11}$'.",
ParameterName: "request"
}
]
},
Action: null,
Code: {
IsPredefinedFault: true,
IsSenderFault: true,
IsReceiverFault: false,
Namespace: "http://schemas.xmlsoap.org/soap/envelope/",
Name: "Client",
SubCode: null
},
Message: "Hubo errores en la validación de los parámetros de la operación.",
Reason: {
Translations: [
{
XmlLang: "en-US",
Text: "Hubo errores en la validación de los parámetros de la operación."
}
]
},
Data: { },
InnerException: null,
TargetSite: {
Name: "HandleReply",
DeclaringType: "System.ServiceModel.Channels.ServiceChannel, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
ReflectedType: "System.ServiceModel.Channels.ServiceChannel, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
MemberType: 8,
MetadataToken: 100671507,
Module: {
MDStreamVersion: 131072,
FullyQualifiedName: "C:\Users\rotha\.nuget\packages\system.private.servicemodel\4.5.3\runtimes\win\lib\netstandard2.0\System.Private.ServiceModel.dll",
ModuleVersionId: "c5851175-5eba-412a-8f03-6cd647a2a897",
MetadataToken: 1,
ScopeName: "System.Private.ServiceModel.dll",
Name: "System.Private.ServiceModel.dll",
Assembly: {
CodeBase: "file:///C:/Users/xxx/.nuget/packages/system.private.servicemodel/4.5.3/runtimes/win/lib/netstandard2.0/System.Private.ServiceModel.dll",
FullName: "System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
EntryPoint: null,
DefinedTypes: [
"FxResources.System.Private.ServiceModel.SR, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
"System.NotImplemented, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
"System.__HResults, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
"System.FxTrace, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
"System.SR, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
"System.Xml.XmlBinaryNodeType, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
"System.Collections.Generic.KeyedByTypeCollection`1, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
"System.Collections.Generic.SynchronizedCollection`1, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
"System.Collections.Generic.SynchronizedKeyedCollection`2, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
"System.Collections.Generic.SynchronizedReadOnlyCollection`1, System.Private.ServiceModel, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a",
..........

this list of defined types, has like a million of items... :(

Its because you are writing the response body to the stream. Instead just pass the info about the exception. — Jaya, Oct 03 '18 at 18:25
i need to send the exception as a json string, i guess i didn't explain that. — Rothariger, Oct 03 '18 at 18:29
Why are you writing the exception to the response? Seems like that would leak details to the consuming application, which doesn't need to know *how* the API failed. Just that it failed. Seems like you should log the error and then write a generic "Something went wrong" response for unhandled exceptions. — mason, Oct 03 '18 at 18:33
but, this i how is working now in full framework, but it doesnt serialize those properties DefinedTypes and TargetSite. — Rothariger, Oct 03 '18 at 18:39
What are the values of [`((DefaultContractResolver)js.ContractResolver).IgnoreSerializableInterface`](https://www.newtonsoft.com/json/help/html/P_Newtonsoft_Json_Serialization_DefaultContractResolver_IgnoreSerializableInterface.htm) and [`((DefaultContractResolver)js.ContractResolver).IgnoreSerializableAttribute`](https://www.newtonsoft.com/json/help/html/P_Newtonsoft_Json_Serialization_DefaultContractResolver_IgnoreSerializableAttribute.htm)? — dbc, Oct 03 '18 at 18:56
Also, what is the type of the exception you are serializing -- i.e. the return of `GetType()`? — dbc, Oct 03 '18 at 19:11
The difference is likely related to [this change](https://stackoverflow.com/a/50881884), but I can't quite pin down where it's happening in the source, since `Exception` is marked as both `[Serializable]` and `ISerializable` in the [.Net core source code](https://github.com/dotnet/coreclr/blob/master/src/System.Private.CoreLib/src/System/Exception.cs) (maybe that's the wrong location for the source?), and I don't have .Net core to debug. Maybe the custom contract resolver from https://stackoverflow.com/a/50881884 will resolve the problem? — dbc, Oct 03 '18 at 19:23
i'm currently trying a System.ServiceModel.EndpointNotFoundException but it could be any exception. — Rothariger, Oct 03 '18 at 19:24
Create a new object with the properties you want. `new { ex.Message, ex.StackTrace, ... }`. — Heretic Monkey, Oct 03 '18 at 23:11
well i have some faultexceptions from WCF services, on those cases that wouldn't work... :( — Rothariger, Oct 03 '18 at 23:16

score 0 · Answer 1 · answered Oct 03 '18 at 22:57

0

There is no need to write it using any writer, just use context.Result:

public class ApiExceptionFilterAttribute : ExceptionFilterAttribute
{
    public override void OnException(ExceptionContext context)
    {
        context.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
        var ex = context.Exception;
        if (ex == null) return;

        context.Result = new JsonResult(ex);
    }
}

answered Oct 03 '18 at 22:57

Alex Riabov

8,655
5
47
48

yes, thanks for the example. But unfortunatelly i'm still getting the 28mb response... :( – Rothariger Oct 03 '18 at 23:10
@Rothariger, well, it means that your serialized exception size is 28mb. Have you configured serializer somewhere? – Alex Riabov Oct 03 '18 at 23:22

score 0 · Answer 2 · answered Dec 14 '18 at 06:49

This should be fixed in Release 12.0.1 of Json.NET:

Change - Excluded TargetSite when serializing Exceptions without SerializableAttribute

The fix was made in commit Exclude TargetSite from non-serializable Exception serialization (#1897) on Oct 27, 2018.

The problem seems to have been introduced in Json.NET 11.0 Release 1:

Change - Types that implement ISerializable but don't have [SerializableAttribute] are not serialized using ISerializable

For discussion about why the change in 11.0.1 was originally made see this answer to Deserializing custom exceptions in Newtonsoft.Json.

Serializing an Exception Return a Very Large JSON

2 Answers2