RxSwift Series (eight)

Objective

In this article we will learn RxSwift about error handling, including:

• Catcherrorjustreturn
• Catcherror
• Retry
• Retry (_:)

Catcherrorjustreturn

errorWhen an event is encountered, it returns a value and ends. More details

let disposeBag = DisposeBag()    let sequenceFail = PublishSubject<String>()    sequenceFail.catchErrorJustReturn("??").subscribe(onNext: {print($0)}).disposed(by: disposeBag)    sequenceFail.onNext("??")sequenceFail.onNext("??")sequenceFail.onError(TestError.test)

Operation Result:

??????

Catcherror

The capture error is processed and can be returned sequence to another subscription. More details

let disposeBag = DisposeBag()    let sequenceThatFails = PublishSubject<String>()let recoverySequence = PublishSubject<String>()    sequenceThatFails.catchError {        print("Error:", $0)        return recoverySequence    }.subscribe { print($0) }.disposed(by: disposeBag)    sequenceThatFails.onNext("??")sequenceThatFails.onNext("??")sequenceThatFails.onNext("??")sequenceThatFails.onError(TestError.test)    recoverySequence.onNext("??")

Operation Result:

next(??)next(??)next(??)Error: testnext(??)

Retry

Encountering the error event can be retried, such as a failed network request and can be reconnected. More details

let disposeBag = DisposeBag()var count = 1    let retrySequence = Observable<String>.create { (observer) -> Disposable in    observer.onNext("??")    observer.onNext("??")            if count == 1 {        observer.onError(TestError.test)        print("Error encountered")        count += 1    }            observer.onNext("??")    observer.onNext("??")            return Disposables.create()}    retrySequence.retry().subscribe(onNext: {print($0)}).disposed(by: disposeBag)

Operation Result:

????Error encountered????????

Retry (_:)
And retryIs the same, only the number of retries is specified.

let disposeBag = DisposeBag()var count = 1    let sequenceThatErrors = Observable<String>.create { observer in    observer.onNext("??")    observer.onNext("??")    observer.onNext("??")            if count < 5 {        observer.onError(TestError.test)        print("Error encountered")        count += 1    }            observer.onNext("??")    observer.onNext("??")    observer.onCompleted()            return Disposables.create()}    sequenceThatErrors.retry(3).subscribe(onNext: { print($0) }).disposed(by: disposeBag)

Operation Result:

??????Error encountered??????Error encountered??????Error encounteredReceived unhandled error: Playground.xcplaygroundpage:41:__lldb_expr_18 -> test

Thanks

If you find the wrong place, welcome to comment, thanks!

RxSwift Series (eight)