Nuqleon.Runtime.Remoting.Tasks

Provides Task<T>-based async support for .NET Remoting including support for cancellation.

Note: .NET Remoting is considered a legacy technology. However, Nuqleon has a so-called "remoting stack" that's been used extensively for testing. This assembly provides base functionality to implement this "remoting stack".

RemoteServiceBase

RemoteServiceBase provides a base class for .NET Remoting services (i.e. a MarshalByRefObject) that support async methods. It contains a single Invoke method for use by derived types. An example of a simple service is shown below:

class CalcService : RemoteServiceBase
{
    public IDisposable Add(int x, int y, IObserver<int> reply) => Invoke(token => AddAsync(x, y, token), reply);

    private async Task<int> AddAsync(int x, int y, CancellationToken token)
    {
        await Task.Delay(5000, token);
        return x + y;
    }
}

Publicly exposed methods use a signature of the form IDisposable Operation(/*args*/, IObserver<T> reply):

• The IDisposable returned will be a MarshalByRefObject that allows the client to cancel the running operation, which gets mapped to a signal on the CancellationToken supplied by Invoke.
• The IObserver<T> passed in will be a MarshalByRefObject for the reply channel that has been manufactured by the client. It's used to flow either a result of type R or an Exception.

The Invoke method converts a Task<T>-based async method with CancellationToken support to this calling convention.

RemoteProxyBase

RemoteProxyBase provides a base class for .NET Remoting clients ("proxies") for corresponding RemoteServiceBase-derived serivces. It contains a single Invoke method for use by derived type. An example of a proxy for the service shown earlier:

class CalcProxy : RemoteProxyBase
{
    private readonly CalcService _svc;

    public TestProxy(CalcService svc)
    {
        _svc = svc;
    }

    public Task<int> AddAsync(int x, int y, CancellationToken token) => Invoke<int>(observer => _svc.Add(x, y, observer), token);
}

The cancellation support supplied via the CancellationToken parameter supports deep cancellation all the way to the corresponding service-side AddAsync method invocation.