SignalR Client C# - Custom Auth Scheme

Is your feature request related to a problem? Please describe.

I’m trying to override the Authorization scheme for C# SignalR Client e.g. not Bearer, however its doesn’t seems possible as it seems to be hardcoded in https://github.com/aspnet/AspNetCore/blob/master/src/SignalR/clients/csharp/Http.Connections.Client/src/Internal/WebSocketsTransport.cs#L116

Describe the solution you’d like

Ability to override the auth shceme, such as

new HubConnectionBuilder()
	.WithUrl(url, opts =>
	{
		opts.AuthScheme = "Secret";
		opts.AccessTokenProvider = () => Task.FromResult("XXX");
	})

Describe alternatives you’ve considered

Another option would be to pass the auth scheme in the AccessTokenProvider itself but might be breaking depends on how it’s handled

[BrennanConroy]

One major issue is that browsers do not allow setting headers on websocket connections. This means we have to send the token in the query string which breaks your auth header logic.

Because we’ve already used access_token for BEARER, and you would need some way to distinguish what the scheme is, we would have to come up with some sort of identifier. Like myscheme_access_token=<token>, or access_token=<token>&scheme=myscheme

[analogrelay]

You can’t include the auth scheme in the AccessTokenProvider, we’ll put Bearer in front of it. So using FooScheme Token would produce a header like Bearer FooScheme Token.

We have some thoughts on custom authentication providers, but until then you can achieve this by adding the header manually and/or using a custom HttpClientHandler. See the SignalR Client Configuration doc for more details.

Backlogging for now as we do think custom authentication is a valuable scenario, we just don’t have capacity in 3.0 for it.