System.Text.Json in SignalR

System.Text.Json is now the default Hub Protocol used by SignalR clients and servers starting in ASP.NET Core 3.0-preview5.

This is my configuration in preview4:

services.AddSignalR().AddNewtonsoftJsonProtocol(options =>
            {
                options.PayloadSerializerSettings.NullValueHandling = NullValueHandling.Ignore;
                options.PayloadSerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
            });

How to migrate this in order to ignore NullValueHandling and ReferenceLoopHandling for SignalR JSON Protocol in preview5?

[BrennanConroy]

I am using https://github.com/dotnet/corefx/issues/36510 to track cyclic references.

You will need to add a reference to “Microsoft.AspNetCore.SignalR.Protocols.NewtonsoftJson” starting in preview5 if you want to continue using Newtonsoft.Json.

[analogrelay]

I believe System.Text.Json does not currently suppport an equivalent to ReferenceLoopHandling and likely won’t support it in 3.0. @joshfree / @ahsonkhan do you know if there’s an issue discussing adding this functionality in the future?

This is a good case where you probably want to continue using Newtonsoft.Json for now. We know that System.Text.Json will not cover all the same cases as Newtonsoft.Json (at least in the initial 3.0 release), so the Newtonsoft.Json package is going to remain in place and fully supported.

For NullValueHandling you can do something similar with this code:

services.AddSignalR()
    .AddJsonProtocol(options => {
        options.PayloadSerializerOptions.IgnoreNullValues = true;
    });