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Merge pull request #240 from tangem/IOS-2715_increase_idle_timeout
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IOS-2715 Resolve NFC issues
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@tureck1y
tureck1y authored Dec 14, 2022
2 parents 652d8f6 + 30a2d37 commit 18f73db
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Showing 2 changed files with 103 additions and 83 deletions.
2 changes: 2 additions & 0 deletions TangemSdk/TangemSdk/Common/Core/CardSession.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -165,6 +165,8 @@ public class CardSession {
reader.viewEventsPublisher //Subscription for reader's view events and invoke viewDelegate
.dropFirst()
.removeDuplicates()
.receive(on: DispatchQueue.main)
.debounce(for: 0.2, scheduler: DispatchQueue.main)
.sink(receiveValue: { [unowned self] event in
switch event {
case .none:
Expand Down
184 changes: 101 additions & 83 deletions TangemSdk/TangemSdk/Common/NFC/NFCReader.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -157,10 +157,10 @@ extension NFCReader: CardReader {
self.tag.send(completion: .failure(error))
self.tag = .init(.none)
} else {
self.tag.send(.none)
self.tagDidDisconnect()
}
isSessionReady = false

self.isSessionReady = false
}
.store(in: &bag)

Expand All @@ -183,36 +183,6 @@ extension NFCReader: CardReader {
}
.store(in: &bag)

//handle tag events
tag
.receive(on: queue)
.dropFirst()
.sink { _ in }
receiveValue: {[unowned self] tag in
if tag != .none {
Log.nfc("Received tag: \(String(describing: tag))")
self.startTagTimer()
if case .tag = tag {
self.startIdleTimer()
}
} else {
Log.nfc("Handle tag lost, cleaning resources: \(String(describing: tag))")
self.tagTimerCancellable = nil
self.idleTimerCancellable = nil
self.searchTimerCancellable = nil
connectedTag = nil
}

if !isPaused && !isSilentRestartPolling {
viewEventsPublisher.send(tag == .none ? .tagLost : .tagConnected)
}

if isSilentRestartPolling && tag != .none { //reset silent mode
isSilentRestartPolling = false
}
}
.store(in: &bag)

restartPollingPublisher //handle restart polling events
.receive(on: queue)
.dropFirst()
Expand All @@ -224,7 +194,7 @@ extension NFCReader: CardReader {

self.isSilentRestartPolling = isSilent
Log.nfc("Restart polling invoked")
self.tag.send(.none)
self.tagDidDisconnect()
session.restartPolling()

if isSilent {
Expand Down Expand Up @@ -265,56 +235,74 @@ extension NFCReader: CardReader {
/// - Parameter completion: result with ResponseApdu or NFCError otherwise
func sendPublisher(apdu: CommandApdu) -> AnyPublisher<ResponseApdu, TangemSdkError> {
Log.nfc("Send publisher invoked")
idleTimerCancellable = nil

guard let connectedTag = self.connectedTag else {
return Empty(completeImmediately: false).eraseToAnyPublisher() //wait for tag
}

guard case let .iso7816(iso7816tag) = connectedTag else {
return Fail(error: TangemSdkError.unsupportedCommand).eraseToAnyPublisher()
} //todo: handle tag lost

let requestTimestamp = Date()
Log.apdu("SEND --> \(apdu)")
return iso7816tag
.sendCommandPublisher(cApdu: apdu)
.combineLatest(cancellationPublisher)
.map { return $0.0 }
.tryCatch{[weak self] error -> AnyPublisher<Result<ResponseApdu, TangemSdkError>, TangemSdkError> in

return Just(())
.setFailureType(to: TangemSdkError.self)
.receive(on: queue)
.handleEvents(receiveOutput: { [weak self] _ in
self?.idleTimerCancellable = nil
})
.flatMap { [weak self] _ -> AnyPublisher<ResponseApdu, TangemSdkError> in
guard let self = self else {
return Empty(completeImmediately: true).eraseToAnyPublisher()
}

if case .userCancelled = error {
return Just(.failure(error))
return Empty()
.setFailureType(to: TangemSdkError.self)
.eraseToAnyPublisher()
}

let distance = requestTimestamp.distance(to: Date())
if distance > Constants.timestampTolerance || self.sendRetryCount <= 0 { //retry to fix old device issues
Log.nfc("Invoke restart polling on error")
self.sendRetryCount = Constants.retryCount
self.restartPolling(silent: true)
return Empty(completeImmediately: false).eraseToAnyPublisher()
} else {
self.sendRetryCount -= 1
Log.nfc("Retry send. distance: \(distance)")
throw error

guard let connectedTag = self.connectedTag else {
return Empty(completeImmediately: false)
.setFailureType(to: TangemSdkError.self)
.eraseToAnyPublisher() //wait for tag
}

guard case let .iso7816(iso7816tag) = connectedTag else {
return Fail(error: TangemSdkError.unsupportedCommand).eraseToAnyPublisher()
} //todo: handle tag lost

let requestTimestamp = Date()
Log.apdu("SEND --> \(apdu)")
return iso7816tag
.sendCommandPublisher(cApdu: apdu)
.combineLatest(self.cancellationPublisher)
.map { return $0.0 }
.receive(on: self.queue)
.tryCatch{[weak self] error -> AnyPublisher<Result<ResponseApdu, TangemSdkError>, TangemSdkError> in
guard let self = self else {
return Empty(completeImmediately: true).eraseToAnyPublisher()
}

if case .userCancelled = error {
return Just(.failure(error))
.setFailureType(to: TangemSdkError.self)
.eraseToAnyPublisher()
}

let distance = requestTimestamp.distance(to: Date())
let isDistanceTooLong = distance > Constants.timestampTolerance
if isDistanceTooLong || self.sendRetryCount <= 0 { //retry to fix old device issues
Log.nfc("Invoke restart polling on error")
self.sendRetryCount = Constants.retryCount
self.restartPolling(silent: !isDistanceTooLong) //Use silent mode only if retries are empty
return Empty(completeImmediately: false).eraseToAnyPublisher()
} else {
self.sendRetryCount -= 1
Log.nfc("Retry send. distance: \(distance)")
throw error
}
}
.retry(Constants.retryCount)
.handleEvents (receiveOutput: {[weak self] rApdu in
guard let self = self else { return }

Log.nfc("Success response from card received")
Log.apdu(rApdu)
self.sendRetryCount = Constants.retryCount
self.startIdleTimer()
})
.tryMap { try $0.getResponse() }
.mapError { $0.toTangemSdkError() }
.eraseToAnyPublisher()
}
.retry(Constants.retryCount)
.handleEvents (receiveOutput: {[weak self] rApdu in
guard let self = self else { return }

Log.nfc("Success response from card received")
Log.apdu(rApdu)
self.sendRetryCount = Constants.retryCount
self.startIdleTimer()
})
.tryMap { try $0.getResponse() }
.mapError { $0.toTangemSdkError() }
.eraseToAnyPublisher()
}

Expand Down Expand Up @@ -402,6 +390,39 @@ extension NFCReader: CardReader {
tagTimerCancellable = nil
idleTimerCancellable = nil
}

private func tagDidDisconnect() {
Log.nfc("Handle tag lost, cleaning resources: \(String(describing: tag))")
tag.send(.none)
connectedTag = nil
tagTimerCancellable = nil
idleTimerCancellable = nil
searchTimerCancellable = nil

if !isPaused && !isSilentRestartPolling {
viewEventsPublisher.send(.tagLost)
}
}

private func tagDidConnect(_ nfcTag: NFCTag) {
connectedTag = nfcTag
let tagType = nfcTag.tagType

Log.nfc("Received tag: \(String(describing: tagType))")

startTagTimer()
if case .tag = tagType {
startIdleTimer()
}

if isSilentRestartPolling { //reset silent mode
isSilentRestartPolling = false
} else if !isPaused {
viewEventsPublisher.send(.tagConnected)
}

tag.send(tagType)
}
}

//MARK: NFCTagReaderSessionDelegate
Expand Down Expand Up @@ -434,10 +455,7 @@ extension NFCReader: NFCTagReaderSessionDelegate {
}
self?.sessionConnectCancellable = nil
} receiveValue: {[weak self] _ in
guard let self = self else { return }

self.connectedTag = nfcTag
self.tag.send(nfcTag.tagType)
self?.tagDidConnect(nfcTag)
}
}
}
Expand All @@ -447,7 +465,7 @@ extension NFCReader: NFCTagReaderSessionDelegate {
extension NFCReader {
enum Constants {
static let tagTimeout = 20.0
static let idleTimeout = 4.0
static let idleTimeout = 2.0
static let sessionTimeout = 60.0
static let nfcStuckTimeout = 1.0
static let retryCount = 20
Expand Down

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