Sending a message to an Azure SignalR service from an Azure Function

Question

User-1202235188 posted

Hi All,

I'm having some trouble getting my head round/finding an example on how to do this.

Currently I've got an Azure SignalR service that is working when triggered from my front end javascript as such;

notifications.server.sendMessage(userId, "Message");

I now have the need for my Azure Function to send messages to the SignalR service too and this is where I'm struggling.

With the following approach I get a 404 error, but I'm convinced the URL, hub name and method name are correct;

public static async void Run([QueueTrigger("signalr-messages", Connection = "Azure.Storage.Main")]string myQueueItem, ILogger log)
{
    Message message = DeserialiseQueueMessage(myQueueItem);

    HubConnection hub = new HubConnection("https://xxxxxxx.service.signalr.net/AzureSignalrPath", false);
    var proxy = hub.CreateHubProxy("BaseHub");
    await hub.Start();
    await proxy.Invoke("SayAnything");
}

With this next approach I'm unsure as to what I should be passing into the function (Obviously the "null" Im currently passing is wrong)

public static async void Run([QueueTrigger("signalr-messages", Connection = "Azure.Storage.Main")]string myQueueItem, ILogger log)
{
    Message message = DeserialiseQueueMessage(myQueueItem);
    SendMessage(null);
}

public static Task SendMessage([SignalR(HubName = "baseHub")]IAsyncCollector<SignalRMessage> signalRMessages)
{
    return signalRMessages.AddAsync(
    new SignalRMessage
    {
        Target = "sendMessage"
    });
}

The last approach I've attempted is using the AzureSignalR class, however I also can't get this to work.

private static async Task SendMessage(Message message)
{
    var signalR = new AzureSignalR(Environment.GetEnvironmentVariable("AzureSignalRConnectionString"));
    await signalR.SendAsync("baseHub", "SayAnything");
}

Does anyone have any experience with these approaches, or can suggest something to point me in the right direction?

Many Thanks,

Tom

Answer 1

User283571144 posted

Hi Tom Kirkland,

Tom Kirkland

HubConnection hub = new HubConnection("https://xxxxxxx.service.signalr.net/AzureSignalrPath", false);

Could you please tell me where you hosted your signalr hub? In local IIS ? or Azure web app?

Best Regards,

Brando

Answer 2

User-1202235188 posted

Brando!

Thank you, you've just solved the issue for me.

HubConnection hub = new HubConnection("URL to signalr service");
var proxy = hub.CreateHubProxy("BaseHub");
hub.Start().Wait();
proxy.Invoke("Send", message.MessageText);

The above was failing me for me, until I I saw your comment and changed it to be;

HubConnection hub = new HubConnection("http://localhost:57690/");
var proxy = hub.CreateHubProxy("BaseHub");
hub.Start().Wait();
proxy.Invoke("Send", message.MessageText);

I figured I would send message to the SignalR service, not to the application which would THEN send to the SignalR service

Thank you!