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Diffstat (limited to 'FireBase/Extensions/ObservableExtensions.cs')
-rw-r--r-- | FireBase/Extensions/ObservableExtensions.cs | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/FireBase/Extensions/ObservableExtensions.cs b/FireBase/Extensions/ObservableExtensions.cs new file mode 100644 index 0000000..12cd5f3 --- /dev/null +++ b/FireBase/Extensions/ObservableExtensions.cs @@ -0,0 +1,40 @@ +namespace Firebase.Database.Extensions +{ + using System; + using System.Reactive.Linq; + + public static class ObservableExtensions + { + /// <summary> + /// Returns a cold observable which retries (re-subscribes to) the source observable on error until it successfully terminates. + /// </summary> + /// <param name="source">The source observable.</param> + /// <param name="dueTime">How long to wait between attempts.</param> + /// <param name="retryOnError">A predicate determining for which exceptions to retry. Defaults to all</param> + /// <returns> + /// A cold observable which retries (re-subscribes to) the source observable on error up to the + /// specified number of times or until it successfully terminates. + /// </returns> + public static IObservable<T> RetryAfterDelay<T, TException>( + this IObservable<T> source, + TimeSpan dueTime, + Func<TException, bool> retryOnError) + where TException: Exception + { + int attempt = 0; + + return Observable.Defer(() => + { + return ((++attempt == 1) ? source : source.DelaySubscription(dueTime)) + .Select(item => new Tuple<bool, T, Exception>(true, item, null)) + .Catch<Tuple<bool, T, Exception>, TException>(e => retryOnError(e) + ? Observable.Throw<Tuple<bool, T, Exception>>(e) + : Observable.Return(new Tuple<bool, T, Exception>(false, default(T), e))); + }) + .Retry() + .SelectMany(t => t.Item1 + ? Observable.Return(t.Item2) + : Observable.Throw<T>(t.Item3)); + } + } +} |