Write an Rx “RetryAfter” extension method

Question

In the book IntroToRx the author suggest to write a \"smart\" retry for I/O which retry an I/O request, like a network request, after a period of time.

Here is the e

Answer 1

Here's the one I came up with.

Didn't want to concatenate the items of individual retries into one sequence, but emit the source sequence as a whole on each retry - so the operator returns an IObservable>. If this is not desired, it can simply be Switch()ed back into one sequence.

(Background: in my use case the source is a hot hot sequence, which I GroupByUntilan item appears that closes the group. If this item is lost between two retries, the group is never closed, resulting in a memory leak. Having a sequence of sequences allows for grouping on the inner sequences only (or exception handling or ...).)

/// 

/// Repeats  in individual windows, with  time in between.
/// 
public static IObservable> RetryAfter(this IObservable source, TimeSpan interval, IScheduler scheduler = null)
{
    if (scheduler == null) scheduler = Scheduler.Default;
    return Observable.Create>(observer =>
    {
        return scheduler.Schedule(self =>
        {
            observer.OnNext(Observable.Create(innerObserver =>
            {
                return source.Subscribe(
                    innerObserver.OnNext,
                    ex => { innerObserver.OnError(ex); scheduler.Schedule(interval, self); },
                    () => { innerObserver.OnCompleted(); scheduler.Schedule(interval, self); });
            }));
        });
    });
}