Microsoft Reciprocal License (Ms-RL)
- corlib - main library
To get started:
Install-Package corlib
Included in the CorLib.Threading namspace, the ToObservable extension method converts a CancellationToken into an IObservable stream that represents the exact same states as a CancellationToken as shown in the extension method's implementation:
public static IObservable<Unit> ToObservable (this CancellationToken cancellationToken, bool onCompleted = false) {
if (cancellationToken.IsCancellationRequested) {
if (onCompleted)
return Observable.Empty<Unit> ();
else
return Observable.Throw<Unit> (new OperationCanceledException ());
}
else if (!cancellationToken.CanBeCanceled)
return Observable.Never<Unit> ();
else
if (onCompleted)
return Observable.Create<Unit> (observer =>
cancellationToken.Register (observer.OnCompleted));
else
return Observable.Create<Unit> (observer =>
cancellationToken.Register (() =>
observer.OnError (new OperationCanceledException ())));
// note that CancellationToken.Register() returns an IDisposable which is disposed of
// when the result observable is unsubscribed from
}Calling Observable.Defer delays exceptions thrown from the abstract method to the Rx sequence which is subsequently picked up by the ToTask extension method who's Result property or Wait method is called from the End APM method, will propragate the exception
using System;
using System.Reactive;
using System.Reactive.Linq;
using System.Web;
namespace CorLib.Web {
/// <summary>
/// Defines the base implementation of Rx HTTP asynchronous handler objects
/// </summary>
public abstract class ObservableHttpHandler : IHttpAsyncHandler {
/// <summary>
/// Async handler implementation
/// </summary>
/// <param name="context">current HTTP context</param>
/// <returns>an observable sequence that signals completion or an error</returns>
protected abstract IObservable<Unit> ProcessRequestAsync (HttpContext context);
/// <remarks>deferrs exceptions to End APM method</remarks>
IAsyncResult IHttpAsyncHandler.BeginProcessRequest (HttpContext context, AsyncCallback cb, object extraData) {
return Observable.Defer<Unit> (() =>
ProcessRequestAsync (context)).ToTask<Unit> (asyncCallback: cb, state: extraData);
}
void IHttpAsyncHandler.EndProcessRequest (IAsyncResult result) {
var task = (Task)result;
task.Wait ();
}
bool IHttpHandler.IsReusable {
get { return true; }
}
void IHttpHandler.ProcessRequest (HttpContext context) {
ProcessRequestAsync (context).ForEach (_ => { });
}
}
}