retryWhen & catchError

2017 - 08 - 30

演示

出现错误后3次重试 且 每次等待时间加长 出现第四次错误后catch

let retryHandler: (Observable<Error>) -> Observable<Int> = { e in  
    return e.flatMapWithIndex { (err, index) -> Observable<Int> in  
        if index > 2 {  
            return Observable.error("Over").observeOn(MainScheduler.instance)  
        }  
        print(Date(), err)  
        return Observable<Int>.timer(Double(index + 1), scheduler: MainScheduler.instance).take(1)  
    }  
}  

Observable<String>.create { (observer) -> Disposable in  
    num = num + 1  
    observer.onError("No. \(num)")  
    return Disposables.create()  
    }  
    .observeOn(MainScheduler.instance)  
    .retryWhen(retryHandler)  
    .catchError { (err) -> Observable<String> in  
        print("catch: ", err)  
        return Observable.just("Go on")  
    }  
    .subscribe { print("------", $0) }  
    .disposed(by: self.bag)  

// 2017-08-30 06:17:34 +0000 No. 1  
// 2017-08-30 06:17:35 +0000 No. 2  
// 2017-08-30 06:17:37 +0000 No. 3  
// catch:  Over  
// ------ next(Go on)  
// ------ completed

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