Missing async versions for Bind<T> and BindAndValidate<T>

From version 10.0 Newtonsoft.Json supports async serialization and deserialization from streams using JToken (and derived).

Would be useful to add the async versions for Bind<T> and BindAndValidate<T> extension methods, which will read the request body in a fully async manner:

var model = await req.BindAsync<MyModel>();
await res.Negotiate(model);

If interested I may send a PR.

[jchannon]

Ah good spot! Thanks.

For asp.net core 3 we will probably move to the new json serializer that comes with it

On Tue, 16 Jul 2019 at 10:17, Stephen Pope [e-mail] wrote:

This seemed the most logical place to put this … I can open up a seperate issue if needed.

I was starting to use Carter (4.2.0) with Netcore 3.0 Preview 6 (3.0.100-preview6-12264).

When trying to call BindAndValidate I get the following error …

System.InvalidOperationException: Synchronous operations are disallowed. Call ReadAsync or set AllowSynchronousIO to true instead. at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpRequestStream.Read(Byte[] buffer, Int32 offset, Int32 count) at System.IO.StreamReader.ReadBuffer(Span1 userBuffer, Boolean& readToUserBuffer) at System.IO.StreamReader.ReadSpan(Span1 buffer) at System.IO.StreamReader.Read(Char[] buffer, Int32 index, Int32 count) at Newtonsoft.Json.JsonTextReader.ReadData(Boolean append, Int32 charsRequired) at Newtonsoft.Json.JsonTextReader.ParseValue() at Newtonsoft.Json.JsonReader.ReadAndMoveToContent() at Newtonsoft.Json.JsonReader.ReadForType(JsonContract contract, Boolean hasConverter) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType) at Newtonsoft.Json.JsonSerializer.Deserialize(JsonReader reader, Type objectType) at Newtonsoft.Json.JsonSerializer.Deserialize[T](JsonReader reader) at Carter.ModelBinding.BindExtensions.Bind[T](HttpRequest request) at Carter.ModelBinding.BindExtensions.BindAndValidate[T](HttpRequest request)

It seems to relate to this announcement -> aspnet/AspNetCore#7644 https://github.com/aspnet/AspNetCore/issues/7644 … that synchronousIO is disallowed by default in NetCore 3.

Adding :

var syncIOFeature = req.HttpContext.Features.Get<IHttpBodyControlFeature>();

if (syncIOFeature != null) { syncIOFeature.AllowSynchronousIO = true; }

… before calling it solves the issue. But it seems that BindAndValidate method is going to blow up by default from NetCore 3 onwards.

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[davidfowl]

Memory stream is a bad idea that’s why we don’t do that 🙂.