How to "get to know" an undocumented SignalR server?

Question

I am writing a c# console client to connect to SignalR service of a server. Using a bit of Wiresharking, Firebugging and examining the .../signalr/hubs document on the server, I was able to connect on the default "/signalr" URL:

    var connection = new HubConnection("https://www.website.com");
    var defaultHub = connection.CreateHubProxy("liveOfferHub");

    connection.Start().ContinueWith(task =>
    {
        if (task.IsFaulted)
        {
            Console.WriteLine("Error opening the connection:" + task.Exception.GetBaseException());
        }
        else
        {
            Console.WriteLine("SignalR Connected");
        }
    }).Wait();

Now I need to find out

• What hubs are there available on the server to connect to? (ask for a list of them)
• What methods can I invoke on the hub? (ask for a list of them)
• What services can I subscribe to? And what will be the names of the events I will be handling, and the classes of the objects I will be receiving?

The IHubManager interface or HubManagerExtensions class look promising, but I was not even able to find out, what classes implement it and how to use it. Asp.net/signalr offers only basic documentation and tutorials.

Thanks in advance for pointing me in the right direction!

Answer 1

I think what you are looking for is something like a WSDL for SignalR.

No, SignalR doesn't have something that complex. What you can get, manually, is from the SignalR proxy: ./signalr/hubs.

If you look at this code from the proxy

proxies.chatHub = this.createHubProxy('chatHub'); //hub name
proxies.chatHub.client = { };
proxies.chatHub.server = {
    serverMethod: function (firstParameter, secondParameter, thridParameter) { //hub method and number of parameters
        return proxies.chatHub.invoke.apply(proxies.chatHub, $.merge(["ServerMethod"], $.makeArray(arguments)));
     }
};

you get only:
- hub names (chatHub)
- server methods and number of parameters (serverMethod, 3 parameters)

So, the only info is that your hub looks something like this:

[HubName("chatHub")]
public class ?? : Hub
{
    public ?? ServerMethod(?? firstParameter, ?? secondParameter, ?? thridParameter)
    {
        ??
    }
}

The client methods are not really in any list and are used on the fly. You can catch them with Fiddler.