An update on setting the signalR userid

My previous blogpost appeared to be a bit outdated and contained not the most recent information. I stated that custom headers couldn't be used with the SignalR ConnectionHubBuilder (at least, the headers got ignored in older versions), but this isn't the case with more recent ConnectionHubBuilder anymore.

I like the use of a custom header to provide the userID more than the querystring approach, as this querystring might appear in browserhistory and logs, this is less the case with custom headers.

The withUrl method does have an optional IHttpConnectionOptions parameter, which has a few properties, with one of them being the headers?: MessageHeaders. A reference can still be found in the documentation (last javascript example):

The headers could be set explicitly, but for some reason, custom headers were not added. a few versions ago (I really don't know what version) this was fixed. With the javascript below, the custom headers can be send (and thus, the UserID can be provided via a custom header).

let messages = document.querySelector('#messages');
    const apiBaseUrl = window.location.origin;
    const headers = { "userid": "bas" }
    const connection = new signalR.HubConnectionBuilder()
        .withUrl(apiBaseUrl + '/api', { headers })
        .configureLogging(signalR.LogLevel.Information)
        .build();

Accordingly, the azure negotiate function needs to be changed as well:

[FunctionName("negotiate")]
public static SignalRConnectionInfo Negotiate(
    [HttpTrigger(AuthorizationLevel.Anonymous)]HttpRequest req,
    [SignalRConnectionInfo(HubName = "chat", UserId = "{headers.userid}")]SignalRConnectionInfo connectionInfo)
{
    // connectionInfo contains an access key token with a name identifier claim set to the identified user
    return connectionInfo;
}