amplify-swift/AmplifyPlugins/Storage/Sources/AWSS3StoragePlugin/Operation/AWSS3StorageDownloadDataOpe...

145 lines
4.3 KiB
Swift

//
// Copyright Amazon.com Inc. or its affiliates.
// All Rights Reserved.
//
// SPDX-License-Identifier: Apache-2.0
//
import Foundation
import Amplify
import AWSPluginsCore
/// Storage Download Data Operation.
///
/// See: [Operations] for more details.
///
/// [Operations]: https://github.com/aws-amplify/amplify-ios/blob/main/OPERATIONS.md
class AWSS3StorageDownloadDataOperation: AmplifyInProcessReportingOperation<
StorageDownloadDataRequest,
Progress,
Data,
StorageError
>, StorageDownloadDataOperation {
let storageConfiguration: AWSS3StoragePluginConfiguration
let storageService: AWSS3StorageServiceBehaviour
let authService: AWSAuthServiceBehavior
var storageTaskReference: StorageTaskReference?
// Serial queue for synchronizing access to `storageTaskReference`.
private let storageTaskActionQueue = DispatchQueue(label: "com.amazonaws.amplify.StorageTaskActionQueue")
init(_ request: StorageDownloadDataRequest,
storageConfiguration: AWSS3StoragePluginConfiguration,
storageService: AWSS3StorageServiceBehaviour,
authService: AWSAuthServiceBehavior,
progressListener: InProcessListener? = nil,
resultListener: ResultListener? = nil) {
self.storageConfiguration = storageConfiguration
self.storageService = storageService
self.authService = authService
super.init(categoryType: .storage,
eventName: HubPayload.EventName.Storage.downloadData,
request: request,
inProcessListener: progressListener,
resultListener: resultListener)
}
/// Pauses operation.
override public func pause() {
storageTaskActionQueue.async {
self.storageTaskReference?.pause()
super.pause()
}
}
/// Resumes operation.
override public func resume() {
storageTaskActionQueue.async {
self.storageTaskReference?.resume()
super.resume()
}
}
/// Cancels operation.
override public func cancel() {
storageTaskActionQueue.async {
self.storageTaskReference?.cancel()
super.cancel()
}
}
/// Performs the task to download data.
override public func main() {
if isCancelled {
finish()
return
}
if let error = request.validate() {
dispatch(error)
finish()
return
}
let prefixResolver = storageConfiguration.prefixResolver ??
StorageAccessLevelAwarePrefixResolver(authService: authService)
Task {
do {
let prefix = try await prefixResolver.resolvePrefix(for: request.options.accessLevel, targetIdentityId: request.options.targetIdentityId)
let serviceKey = prefix + request.key
storageService.download(serviceKey: serviceKey, fileURL: nil) { [weak self] event in
self?.onServiceEvent(event: event)
}
} catch {
dispatch(StorageError(error: error))
finish()
}
}
}
private func onServiceEvent(event: StorageEvent<StorageTaskReference, Progress, Data?, StorageError>) {
switch event {
case .initiated(let reference):
storageTaskActionQueue.async {
self.storageTaskReference = reference
if self.isCancelled {
self.storageTaskReference?.cancel()
self.finish()
}
}
case .inProcess(let progress):
dispatch(progress)
case .completed(let result):
guard let data = result else {
dispatch(StorageError.unknown("this should never be the case here"))
finish()
return
}
dispatch(data)
finish()
case .failed(let error):
dispatch(error)
finish()
}
}
private func dispatch(_ progress: Progress) {
dispatchInProcess(data: progress)
}
private func dispatch(_ result: Data) {
let result = OperationResult.success(result)
dispatch(result: result)
}
private func dispatch(_ error: StorageError) {
let result = OperationResult.failure(error)
dispatch(result: result)
}
}