SignalR.Client.TypedHubProxy

SignalR.Client.TypedHubProxy is a library which extends the SignalR.Client components.

What can it be used for?

One thing that really bugged me out about SignalR is the lack of strongly typed hub proxies. This library will enable this feature via interface implementations.

Get it on NuGet!

https://www.nuget.org/packages/SignalR.Client.TypedHubProxy

or

Install-Package SignalR.Client.TypedHubProxy

LICENSE

Apache 2.0 License

Example

First of all we have to declare the interfaces:

public interface IServerHub
{
    void DoSomething();
    void DoSomethingWithParam(int id);
    int DoSomethingWithParamAndResult(int id);
}

public interface IClientContract
{
    void SomeInformation();
    void SomeInformationWithParam(int id);
}

After that, we have to implement the ServerHub which implements IServerHub and uses IClientContract:

public class ServerHub : Microsoft.AspNet.SignalR.Hub<IClientContract>, IServerHub
{
    public void DoSomething()
    {
        System.Console.WriteLine("DoSomething called.");
    }

    public void DoSomethingWithParam(int id)
    {
        System.Console.WriteLine("DoSomethingWithParam called.");
    }

    public int DoSomethingWithParamAndResult(int id)
    {
        System.Console.WriteLine("DoSomethingWithParamAndResult called.");
        return id;
    }
}

At the client, we have to set up the connection:

var hubConnection = new Microsoft.AspNet.SignalR.Client.HubConnection("http://localhost:1337/signalr");

Invocations

The next part is the interesting one - The usage of the strongly typed HubProxy. To understand exactly what the TypedHubProxy does, here an example of how it is used normally:

Microsoft.AspNet.SignalR.Client.IHubProxy hubProxy = hubConnection.CreateHubProxy("serverHub");
hubProxy.Invoke("DoSomething", new object[0]);

What really bugged me out was the lack of strongly typed invocation. So SignalR.Client.TypedHubProxy enables strongly typed invocation and much more. The following code sample shows you exactly what can it be used for:

IHubProxy<IServerHub, IClientContract> hubProxy = hubConnection.CreateHubProxy<IServerHub, IClientContract>("serverHub");

// Here you can define the method which should be called - strongly typed.
hubProxy.Call(hub => hub.DoSomething());

// For methods with parameters, just handover the parameter.
hubProxy.Call(hub => hub.DoSomethingWithParam(5));

// For methods with a result, you can receive it as expected.
int result = hubProxy.Call<int>(hub => hub.DoSomethingWithParamAndResult(5));

Async calls are also possible:

hubProxy.CallAsync(hub => hub.DoSomething());
hubProxy.CallAsync(hub => hub.DoSomethingWithParam(5));
System.Threading.Tasks.Task<int> asyncResult = hubProxy.CallAsync(hub => hub.DoSomethingWithParamAndResult(5));
int result = asyncResult.Result; // or just: int result = hubProxy.CallAsync(hub => hub.DoSomethingWithParamAndResult(5)).Result;

Subscriptions

The old way:

Microsoft.AspNet.SignalR.Client.IHubProxy hubProxy = hubConnection.CreateHubProxy("serverHub");
hubProxy.On<int>("SomeInformationWithParam", i => System.Console.WriteLine("Got new information: {0}", i));

And the new way with SignalR.Client.TypedHubProxy:

IHubProxy<IServerHub, IClientContract> hubProxy = hubConnection.CreateHubProxy<IServerHub, IClientContract>("serverHub");
hubProxy.SubscribeOn(hub => hub.SomeInformation, () => System.Console.WriteLine("Got some new information."));
hubProxy.SubscribeOn<int>(hub => hub.SomeInformationWithParam, i => System.Console.WriteLine("Got new information: {0}", i));

It's also possible to define a condition on the subscription, so that you will be only called if the condition is true:

IHubProxy<IServerHub, IClientContract> hubProxy = hubConnection.CreateHubProxy<IServerHub, IClientContract>("serverHub");
hubProxy.SubscribeOn<int>(hub => hub.SomeInformationWithParam, i => i == 5, i => System.Console.WriteLine("Got new information where data == 5"));

Observable

System.IObservable<int> observableResult = hubProxy.Observe<int>(hub => hub.SomeInformationWithParam);