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Unable to send SignalR message to group via [SignalROutput] output binding

See original GitHub issue

In the negotiate, I add the current user to a group. When I trigger a message to all users, the message is received and displayed successfully in my PoC HTML/JS client. When I trigger a message to a specific group, no message is received. Even though each connection should have been added to the group.

My Poc Client

    [Function("index")]
    public static HttpResponseData GetWebPage([HttpTrigger(AuthorizationLevel.Anonymous)] HttpRequestData req)
    {
        var response = req.CreateResponse(HttpStatusCode.OK);
        response.WriteString(File.ReadAllText("content/index.html"));
        response.Headers.Add("Content-Type", "text/html");
        return response;
    }

Client html (taken from Sample)

<html>

<body>
  <h1>Azure SignalR Serverless Sample</h1>
  <div id="messages"></div>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/microsoft-signalr/3.1.7/signalr.min.js"></script>
  <script>
    let messages = document.querySelector('#messages');
    const apiBaseUrl = window.location.origin;
    const connection = new signalR.HubConnectionBuilder()
        .withUrl(apiBaseUrl + '/api')
        .configureLogging(signalR.LogLevel.Information)
        .build();
      connection.on('newMessage', (message) => {
        document.getElementById("messages").innerHTML = message;
      });

      connection.start()
        .catch(console.error);
  </script>
</body>

</html>

My Azure Functions

     [Function("negotiate")]
    public async Task<NegotiateGroupAction> Negotiate(
        [HttpTrigger(AuthorizationLevel.Anonymous)] HttpRequestData req,
        [SignalRConnectionInfoInput(HubName = "hub")] SignalRConnectionInfo connectionInfo)
    {
        var signalRGroupAction = new SignalRGroupAction(SignalRGroupActionType.Add)
        {
            GroupName = "testGroup",
            UserId = "user1" 
        };

        var httpResponse = req.CreateResponse(HttpStatusCode.OK);
        await httpResponse.WriteAsJsonAsync(connectionInfo);
        
        return new NegotiateGroupAction
        {
            SignalRGroupAction = signalRGroupAction,
            HttpResponseData = httpResponse  
        };
    }

    [Function(nameof(SendToGroup))]
    [SignalROutput(HubName = "hub")]
    public async Task<SignalRMessageAction> SendToGroup([HttpTrigger(AuthorizationLevel.Anonymous, "post")] HttpRequestData req)
    {
        return new SignalRMessageAction("newMessage")
        {
            GroupName = "testGroup",
            Arguments = new[] { await req.ReadAsStringAsync() },
        };
    }
    
    [Function(nameof(Broadcast))]
    [SignalROutput(HubName = "hub")]
    public async Task<SignalRMessageAction> Broadcast([HttpTrigger(AuthorizationLevel.Anonymous, "post")] HttpRequestData req)
    {
        return new SignalRMessageAction("newMessage")
        {
            Arguments = new[] { await req.ReadAsStringAsync() },
        };
    }


// POCO to support multiple output bindings, in this case, HttpResponseData + SignalRGroupAction
public class NegotiateGroupAction
{
    [SignalROutput(HubName = "deploymentlogs", ConnectionStringSetting = "AzureSignalRConnectionString")]
    public SignalRGroupAction SignalRGroupAction { get; set; }
    public HttpResponseData HttpResponseData { get; set; }
}

When changing the log level to TRACE I can see the calls to the SignalR Service api are there and getting OK responses. So the output bindings do work. Still, no message is received when sending a message to a group.

Issue Analytics

State:
Created 2 months ago
Comments:5 (3 by maintainers)

Top GitHub Comments

1reaction

Y-Sindocommented, Aug 3, 2023

@vlflorian at the point of negotiation, the SignalR client connection is not established yet. Therefore, it’s no way for SignalR service to know that the current client who makes the HTTP request is linked to the user ‘user1’. By specifying a user ID in the negotiation, a claim indicating the username is set in the JWT access token returned to the client. Only in this way, when the client comes to the service and establishes a SignalR connection with the JWT, the service will link the SignalR connection with that user name.

0reactions

vlfloriancommented, Aug 3, 2023

@Y-Sindo thank you for the explanation, that makes sense.

I would suggest this to be added somewhere in the documentation, though. It’s hard enough already to find usable docs and actual samples for SignalR with Azure Functions dotnet isolated, and even then basic things like these aren’t mentioned anywhere.