MvcOptions.InputFormatters doesn't work on asp.net vnext beta7

Question

My application stopped working after migrating to beta 6/7, after investigating, I have found that my json deserializer is no more used ( Jil ), it's called for writing but not for reading.

It has been now 3 days that I'm searching forums and reading aspnet code but I haven't found the issue.

I noticed that JSON.net is used everywhere in beta 6, a little bit less in beta 7.

Here is my code :

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvcCore(options =>
        {
            var jilFormatter = new JilMediaTypeFormatter();
            options.OutputFormatters.Clear();
            options.OutputFormatters.Add(jilFormatter);
            options.InputFormatters.Clear();
            options.InputFormatters.Add(jilFormatter);

            options.FormatterMappings.SetMediaTypeMappingForFormat("json", MediaTypeHeaderValue.Parse("application/json"));

            options.ModelBinders.Add(new DocumentModelBinder());
            options.ModelBinders.Add(new DataTablesBinder());
        });
        services.AddDataProtection();
        services.AddWebEncoders();

    }

Even if I do just InputFormatters.Clear() without adding an object, it keeps deserializing the requests, I have no idea how it does it.

And my JIL InputFormatter/OutputFormatter ( the ouputformatter works, I can break in the CanWrite, but nothing happens for CanRead )

internal class JilMediaTypeFormatter : IOutputFormatter, IInputFormatter
{
    private static readonly string [] _readableTypes = new[] { "application/json", "text/json", "text/javascript" };
    private static readonly Task<bool> _done = Task.FromResult(true);

    private readonly Options _options = Options.RFC1123ExcludeNullsIncludeInherited;


    public bool CanWriteResult(OutputFormatterContext context, Microsoft.Net.Http.Headers.MediaTypeHeaderValue contentType)
    {
        return contentType ==null || _readableTypes.Contains(contentType.MediaType.ToLowerInvariant());
    }

    public Task WriteAsync(OutputFormatterContext context)
    {
        context.HttpContext.Response.ContentType = "application/json";
        using (var writer = new StreamWriter(context.HttpContext.Response.Body))
        {
            JSON.Serialize(context.Object, writer, _options);
            writer.Flush();
            return _done;
        }
    }

    public bool CanRead(InputFormatterContext context)
    {
        return _readableTypes.Contains(context.HttpContext.Request.ContentType);
    }

    public Task<object> ReadAsync(InputFormatterContext context)
    {
        var reader = new StreamReader(context.HttpContext.Request.Body);
        var result = JSON.Deserialize(reader, context.ModelType, _options);
        return Task.FromResult(result);
    }
}

Answer 1

InputFormatters are used only when [FromBody] is used in the parameter's list of the action.