Azure Funxtion - SignalR connection string or endpoints are not set

Question

I want to implement SignalR in C#/.net (3.1) for an Azure Function with an extended negotiate function, so that messages can be send to a specific user.

The basic negotiate for broadcasting is working.

   [FunctionName("negotiate")]
    public static SignalRConnectionInfo GetSignalRInfo(
      [HttpTrigger(AuthorizationLevel.Function, "post")] HttpRequest req,
      [SignalRConnectionInfo(HubName = "myHub")] SignalRConnectionInfo connectionInfo)
    {
        return connectionInfo;
    }

Now I wanted to use the extended Version from the MS documentation:

[FunctionName("negotiate")]
        public static SignalRConnectionInfo GetSignalRInfo(
            [HttpTrigger(AuthorizationLevel.Function, "post")] HttpRequest req,
            [SignalRConnectionInfo(HubName = "myHub", UserId = "{headers.x-ms-client-principal-id}")] SignalRConnectionInfo connectionInfo)
        {
            // connectionInfo contains an access key token with a name identifier claim set to the authenticated user
            return connectionInfo;
        }

This wont work, like discussed in this article: https://charliedigital.com/2019/09/02/azure-functions-signalr-and-authorization/

So I rewrite my negotiate function like this:

[FunctionName("negotiate")]
        public static async Task GetSignalRInfo(ILogger log,
    [HttpTrigger(AuthorizationLevel.Anonymous, "post")] HttpRequest req,
    IBinder binder)
        {
            string userId = req.Headers["x-user-id-header"]; // This value is here, but not available in the binding for the attribute
            string signalREndpoint = Environment.GetEnvironmentVariable("SignalR_ENDPOINT", EnvironmentVariableTarget.Process);

            log.LogInformation("Called negotiate with userID: " + userId + " and SignalR Endpoint: " + signalREndpoint);

            SignalRConnectionInfoAttribute attribute = new SignalRConnectionInfoAttribute
            {
                ConnectionStringSetting = signalREndpoint,
                HubName = "myHub",
                UserId = userId
            };

            // This style is an example of imperative attribute binding; the mechanism for declarative binding described below does not work
            // UserId = "{headers.x-my-custom-header}" https://docs.microsoft.com/en-us/azure/azure-signalr/signalr-concept-serverless-development-config
            SignalRConnectionInfo connection = await binder.BindAsync(attribute);

            return connection;
        }

But now I get the following error:

Executed 'negotiate' (Failed, Id=df9db581-2251-4fb1-b1b5-5f53b173533e, Duration=465ms) [2022-07-13T13:31:00.871Z] System.Private.CoreLib: Exception while executing function: negotiate. Microsoft.Azure.WebJobs.Extensions.SignalRService: The SignalR Service connection string or endpoints are not set.

The Endpoint is correctly read from the local.json and the name of the hub is also correct.

What am I missing here?

Azure Funxtion - SignalR connection string or endpoints are not set

0 Answers