Check in Azure Functions if client is still connected to SignalR Service

Question

I've created negotiate and send message functions in Azure Functions (similar to the samples below) to incorporate the SignalR Service. I'm setting UserId on the SignalRMessage by using a custom authentication mechanism.

https://docs.microsoft.com/en-us/azure/azure-functions/functions-bindings-signalr-service?tabs=csharp

[FunctionName("negotiate")]
public static SignalRConnectionInfo Negotiate(
    [HttpTrigger(AuthorizationLevel.Anonymous)]HttpRequest req, 
    [SignalRConnectionInfo
        (HubName = "chat", 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;
}

[FunctionName("SendMessage")]
public static Task SendMessage(
    [HttpTrigger(AuthorizationLevel.Anonymous, "post")]object message, 
    [SignalR(HubName = "chat")]IAsyncCollector<SignalRMessage> signalRMessages)
{
    return signalRMessages.AddAsync(
        new SignalRMessage 
        {
            // the message will only be sent to this user ID
            UserId = "userId1",
            Target = "newMessage",
            Arguments = new [] { message }
        });
}

I'd like to send a push notification if the client is no longer connected instead of adding a new object to the IAsyncCollector . I've also set up AppCenter push framework properly, but I'm facing an issue. Is there an easy way to find out which UserId is still connected to the hub? This way, I could decide to send a push. What is the recommended Microsoft guidance on this issue?

Answer 1

Have a look at this feature: Azure SignalR Service introduces Event Grid integration feature , where the SignalR Service emits two following event types:

Microsoft.SignalRService.ClientConnectionConnected

Microsoft.SignalRService.ClientConnectionDisconnected

More details here .