Files
swiftGrammar/Pods/Alamofire/Source/Core/Request.swift
2024-08-12 10:49:20 +08:00

1091 lines
43 KiB
Swift

//
// Request.swift
//
// Copyright (c) 2014-2024 Alamofire Software Foundation (http://alamofire.org/)
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
import Foundation
/// `Request` is the common superclass of all Alamofire request types and provides common state, delegate, and callback
/// handling.
public class Request {
/// State of the `Request`, with managed transitions between states set when calling `resume()`, `suspend()`, or
/// `cancel()` on the `Request`.
public enum State {
/// Initial state of the `Request`.
case initialized
/// `State` set when `resume()` is called. Any tasks created for the `Request` will have `resume()` called on
/// them in this state.
case resumed
/// `State` set when `suspend()` is called. Any tasks created for the `Request` will have `suspend()` called on
/// them in this state.
case suspended
/// `State` set when `cancel()` is called. Any tasks created for the `Request` will have `cancel()` called on
/// them. Unlike `resumed` or `suspended`, once in the `cancelled` state, the `Request` can no longer transition
/// to any other state.
case cancelled
/// `State` set when all response serialization completion closures have been cleared on the `Request` and
/// enqueued on their respective queues.
case finished
/// Determines whether `self` can be transitioned to the provided `State`.
func canTransitionTo(_ state: State) -> Bool {
switch (self, state) {
case (.initialized, _):
return true
case (_, .initialized), (.cancelled, _), (.finished, _):
return false
case (.resumed, .cancelled), (.suspended, .cancelled), (.resumed, .suspended), (.suspended, .resumed):
return true
case (.suspended, .suspended), (.resumed, .resumed):
return false
case (_, .finished):
return true
}
}
}
// MARK: - Initial State
/// `UUID` providing a unique identifier for the `Request`, used in the `Hashable` and `Equatable` conformances.
public let id: UUID
/// The serial queue for all internal async actions.
public let underlyingQueue: DispatchQueue
/// The queue used for all serialization actions. By default it's a serial queue that targets `underlyingQueue`.
public let serializationQueue: DispatchQueue
/// `EventMonitor` used for event callbacks.
public let eventMonitor: EventMonitor?
/// The `Request`'s interceptor.
public let interceptor: RequestInterceptor?
/// The `Request`'s delegate.
public private(set) weak var delegate: RequestDelegate?
// MARK: - Mutable State
/// Type encapsulating all mutable state that may need to be accessed from anything other than the `underlyingQueue`.
struct MutableState {
/// State of the `Request`.
var state: State = .initialized
/// `ProgressHandler` and `DispatchQueue` provided for upload progress callbacks.
var uploadProgressHandler: (handler: ProgressHandler, queue: DispatchQueue)?
/// `ProgressHandler` and `DispatchQueue` provided for download progress callbacks.
var downloadProgressHandler: (handler: ProgressHandler, queue: DispatchQueue)?
/// `RedirectHandler` provided for to handle request redirection.
var redirectHandler: RedirectHandler?
/// `CachedResponseHandler` provided to handle response caching.
var cachedResponseHandler: CachedResponseHandler?
/// Queue and closure called when the `Request` is able to create a cURL description of itself.
var cURLHandler: (queue: DispatchQueue, handler: (String) -> Void)?
/// Queue and closure called when the `Request` creates a `URLRequest`.
var urlRequestHandler: (queue: DispatchQueue, handler: (URLRequest) -> Void)?
/// Queue and closure called when the `Request` creates a `URLSessionTask`.
var urlSessionTaskHandler: (queue: DispatchQueue, handler: (URLSessionTask) -> Void)?
/// Response serialization closures that handle response parsing.
var responseSerializers: [() -> Void] = []
/// Response serialization completion closures executed once all response serializers are complete.
var responseSerializerCompletions: [() -> Void] = []
/// Whether response serializer processing is finished.
var responseSerializerProcessingFinished = false
/// `URLCredential` used for authentication challenges.
var credential: URLCredential?
/// All `URLRequest`s created by Alamofire on behalf of the `Request`.
var requests: [URLRequest] = []
/// All `URLSessionTask`s created by Alamofire on behalf of the `Request`.
var tasks: [URLSessionTask] = []
/// All `URLSessionTaskMetrics` values gathered by Alamofire on behalf of the `Request`. Should correspond
/// exactly the the `tasks` created.
var metrics: [URLSessionTaskMetrics] = []
/// Number of times any retriers provided retried the `Request`.
var retryCount = 0
/// Final `AFError` for the `Request`, whether from various internal Alamofire calls or as a result of a `task`.
var error: AFError?
/// Whether the instance has had `finish()` called and is running the serializers. Should be replaced with a
/// representation in the state machine in the future.
var isFinishing = false
/// Actions to run when requests are finished. Use for concurrency support.
var finishHandlers: [() -> Void] = []
}
/// Protected `MutableState` value that provides thread-safe access to state values.
let mutableState = Protected(MutableState())
/// `State` of the `Request`.
public var state: State { mutableState.state }
/// Returns whether `state` is `.initialized`.
public var isInitialized: Bool { state == .initialized }
/// Returns whether `state` is `.resumed`.
public var isResumed: Bool { state == .resumed }
/// Returns whether `state` is `.suspended`.
public var isSuspended: Bool { state == .suspended }
/// Returns whether `state` is `.cancelled`.
public var isCancelled: Bool { state == .cancelled }
/// Returns whether `state` is `.finished`.
public var isFinished: Bool { state == .finished }
// MARK: Progress
/// Closure type executed when monitoring the upload or download progress of a request.
public typealias ProgressHandler = (Progress) -> Void
/// `Progress` of the upload of the body of the executed `URLRequest`. Reset to `0` if the `Request` is retried.
public let uploadProgress = Progress(totalUnitCount: 0)
/// `Progress` of the download of any response data. Reset to `0` if the `Request` is retried.
public let downloadProgress = Progress(totalUnitCount: 0)
/// `ProgressHandler` called when `uploadProgress` is updated, on the provided `DispatchQueue`.
public internal(set) var uploadProgressHandler: (handler: ProgressHandler, queue: DispatchQueue)? {
get { mutableState.uploadProgressHandler }
set { mutableState.uploadProgressHandler = newValue }
}
/// `ProgressHandler` called when `downloadProgress` is updated, on the provided `DispatchQueue`.
public internal(set) var downloadProgressHandler: (handler: ProgressHandler, queue: DispatchQueue)? {
get { mutableState.downloadProgressHandler }
set { mutableState.downloadProgressHandler = newValue }
}
// MARK: Redirect Handling
/// `RedirectHandler` set on the instance.
public internal(set) var redirectHandler: RedirectHandler? {
get { mutableState.redirectHandler }
set { mutableState.redirectHandler = newValue }
}
// MARK: Cached Response Handling
/// `CachedResponseHandler` set on the instance.
public internal(set) var cachedResponseHandler: CachedResponseHandler? {
get { mutableState.cachedResponseHandler }
set { mutableState.cachedResponseHandler = newValue }
}
// MARK: URLCredential
/// `URLCredential` used for authentication challenges. Created by calling one of the `authenticate` methods.
public internal(set) var credential: URLCredential? {
get { mutableState.credential }
set { mutableState.credential = newValue }
}
// MARK: Validators
/// `Validator` callback closures that store the validation calls enqueued.
let validators = Protected<[() -> Void]>([])
// MARK: URLRequests
/// All `URLRequest`s created on behalf of the `Request`, including original and adapted requests.
public var requests: [URLRequest] { mutableState.requests }
/// First `URLRequest` created on behalf of the `Request`. May not be the first one actually executed.
public var firstRequest: URLRequest? { requests.first }
/// Last `URLRequest` created on behalf of the `Request`.
public var lastRequest: URLRequest? { requests.last }
/// Current `URLRequest` created on behalf of the `Request`.
public var request: URLRequest? { lastRequest }
/// `URLRequest`s from all of the `URLSessionTask`s executed on behalf of the `Request`. May be different from
/// `requests` due to `URLSession` manipulation.
public var performedRequests: [URLRequest] { mutableState.read { $0.tasks.compactMap(\.currentRequest) } }
// MARK: HTTPURLResponse
/// `HTTPURLResponse` received from the server, if any. If the `Request` was retried, this is the response of the
/// last `URLSessionTask`.
public var response: HTTPURLResponse? { lastTask?.response as? HTTPURLResponse }
// MARK: Tasks
/// All `URLSessionTask`s created on behalf of the `Request`.
public var tasks: [URLSessionTask] { mutableState.tasks }
/// First `URLSessionTask` created on behalf of the `Request`.
public var firstTask: URLSessionTask? { tasks.first }
/// Last `URLSessionTask` created on behalf of the `Request`.
public var lastTask: URLSessionTask? { tasks.last }
/// Current `URLSessionTask` created on behalf of the `Request`.
public var task: URLSessionTask? { lastTask }
// MARK: Metrics
/// All `URLSessionTaskMetrics` gathered on behalf of the `Request`. Should correspond to the `tasks` created.
public var allMetrics: [URLSessionTaskMetrics] { mutableState.metrics }
/// First `URLSessionTaskMetrics` gathered on behalf of the `Request`.
public var firstMetrics: URLSessionTaskMetrics? { allMetrics.first }
/// Last `URLSessionTaskMetrics` gathered on behalf of the `Request`.
public var lastMetrics: URLSessionTaskMetrics? { allMetrics.last }
/// Current `URLSessionTaskMetrics` gathered on behalf of the `Request`.
public var metrics: URLSessionTaskMetrics? { lastMetrics }
// MARK: Retry Count
/// Number of times the `Request` has been retried.
public var retryCount: Int { mutableState.retryCount }
// MARK: Error
/// `Error` returned from Alamofire internally, from the network request directly, or any validators executed.
public internal(set) var error: AFError? {
get { mutableState.error }
set { mutableState.error = newValue }
}
/// Default initializer for the `Request` superclass.
///
/// - Parameters:
/// - id: `UUID` used for the `Hashable` and `Equatable` implementations. `UUID()` by default.
/// - underlyingQueue: `DispatchQueue` on which all internal `Request` work is performed.
/// - serializationQueue: `DispatchQueue` on which all serialization work is performed. By default targets
/// `underlyingQueue`, but can be passed another queue from a `Session`.
/// - eventMonitor: `EventMonitor` called for event callbacks from internal `Request` actions.
/// - interceptor: `RequestInterceptor` used throughout the request lifecycle.
/// - delegate: `RequestDelegate` that provides an interface to actions not performed by the `Request`.
init(id: UUID = UUID(),
underlyingQueue: DispatchQueue,
serializationQueue: DispatchQueue,
eventMonitor: EventMonitor?,
interceptor: RequestInterceptor?,
delegate: RequestDelegate) {
self.id = id
self.underlyingQueue = underlyingQueue
self.serializationQueue = serializationQueue
self.eventMonitor = eventMonitor
self.interceptor = interceptor
self.delegate = delegate
}
// MARK: - Internal Event API
// All API must be called from underlyingQueue.
/// Called when an initial `URLRequest` has been created on behalf of the instance. If a `RequestAdapter` is active,
/// the `URLRequest` will be adapted before being issued.
///
/// - Parameter request: The `URLRequest` created.
func didCreateInitialURLRequest(_ request: URLRequest) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
mutableState.write { $0.requests.append(request) }
eventMonitor?.request(self, didCreateInitialURLRequest: request)
}
/// Called when initial `URLRequest` creation has failed, typically through a `URLRequestConvertible`.
///
/// - Note: Triggers retry.
///
/// - Parameter error: `AFError` thrown from the failed creation.
func didFailToCreateURLRequest(with error: AFError) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
self.error = error
eventMonitor?.request(self, didFailToCreateURLRequestWithError: error)
callCURLHandlerIfNecessary()
retryOrFinish(error: error)
}
/// Called when a `RequestAdapter` has successfully adapted a `URLRequest`.
///
/// - Parameters:
/// - initialRequest: The `URLRequest` that was adapted.
/// - adaptedRequest: The `URLRequest` returned by the `RequestAdapter`.
func didAdaptInitialRequest(_ initialRequest: URLRequest, to adaptedRequest: URLRequest) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
mutableState.write { $0.requests.append(adaptedRequest) }
eventMonitor?.request(self, didAdaptInitialRequest: initialRequest, to: adaptedRequest)
}
/// Called when a `RequestAdapter` fails to adapt a `URLRequest`.
///
/// - Note: Triggers retry.
///
/// - Parameters:
/// - request: The `URLRequest` the adapter was called with.
/// - error: The `AFError` returned by the `RequestAdapter`.
func didFailToAdaptURLRequest(_ request: URLRequest, withError error: AFError) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
self.error = error
eventMonitor?.request(self, didFailToAdaptURLRequest: request, withError: error)
callCURLHandlerIfNecessary()
retryOrFinish(error: error)
}
/// Final `URLRequest` has been created for the instance.
///
/// - Parameter request: The `URLRequest` created.
func didCreateURLRequest(_ request: URLRequest) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
mutableState.read { state in
state.urlRequestHandler?.queue.async { state.urlRequestHandler?.handler(request) }
}
eventMonitor?.request(self, didCreateURLRequest: request)
callCURLHandlerIfNecessary()
}
/// Asynchronously calls any stored `cURLHandler` and then removes it from `mutableState`.
private func callCURLHandlerIfNecessary() {
mutableState.write { mutableState in
guard let cURLHandler = mutableState.cURLHandler else { return }
cURLHandler.queue.async { cURLHandler.handler(self.cURLDescription()) }
mutableState.cURLHandler = nil
}
}
/// Called when a `URLSessionTask` is created on behalf of the instance.
///
/// - Parameter task: The `URLSessionTask` created.
func didCreateTask(_ task: URLSessionTask) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
mutableState.write { state in
state.tasks.append(task)
guard let urlSessionTaskHandler = state.urlSessionTaskHandler else { return }
urlSessionTaskHandler.queue.async { urlSessionTaskHandler.handler(task) }
}
eventMonitor?.request(self, didCreateTask: task)
}
/// Called when resumption is completed.
func didResume() {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
eventMonitor?.requestDidResume(self)
}
/// Called when a `URLSessionTask` is resumed on behalf of the instance.
///
/// - Parameter task: The `URLSessionTask` resumed.
func didResumeTask(_ task: URLSessionTask) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
eventMonitor?.request(self, didResumeTask: task)
}
/// Called when suspension is completed.
func didSuspend() {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
eventMonitor?.requestDidSuspend(self)
}
/// Called when a `URLSessionTask` is suspended on behalf of the instance.
///
/// - Parameter task: The `URLSessionTask` suspended.
func didSuspendTask(_ task: URLSessionTask) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
eventMonitor?.request(self, didSuspendTask: task)
}
/// Called when cancellation is completed, sets `error` to `AFError.explicitlyCancelled`.
func didCancel() {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
mutableState.write { mutableState in
mutableState.error = mutableState.error ?? AFError.explicitlyCancelled
}
eventMonitor?.requestDidCancel(self)
}
/// Called when a `URLSessionTask` is cancelled on behalf of the instance.
///
/// - Parameter task: The `URLSessionTask` cancelled.
func didCancelTask(_ task: URLSessionTask) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
eventMonitor?.request(self, didCancelTask: task)
}
/// Called when a `URLSessionTaskMetrics` value is gathered on behalf of the instance.
///
/// - Parameter metrics: The `URLSessionTaskMetrics` gathered.
func didGatherMetrics(_ metrics: URLSessionTaskMetrics) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
mutableState.write { $0.metrics.append(metrics) }
eventMonitor?.request(self, didGatherMetrics: metrics)
}
/// Called when a `URLSessionTask` fails before it is finished, typically during certificate pinning.
///
/// - Parameters:
/// - task: The `URLSessionTask` which failed.
/// - error: The early failure `AFError`.
func didFailTask(_ task: URLSessionTask, earlyWithError error: AFError) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
self.error = error
// Task will still complete, so didCompleteTask(_:with:) will handle retry.
eventMonitor?.request(self, didFailTask: task, earlyWithError: error)
}
/// Called when a `URLSessionTask` completes. All tasks will eventually call this method.
///
/// - Note: Response validation is synchronously triggered in this step.
///
/// - Parameters:
/// - task: The `URLSessionTask` which completed.
/// - error: The `AFError` `task` may have completed with. If `error` has already been set on the instance, this
/// value is ignored.
func didCompleteTask(_ task: URLSessionTask, with error: AFError?) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
self.error = self.error ?? error
let validators = validators.read { $0 }
validators.forEach { $0() }
eventMonitor?.request(self, didCompleteTask: task, with: error)
retryOrFinish(error: self.error)
}
/// Called when the `RequestDelegate` is going to retry this `Request`. Calls `reset()`.
func prepareForRetry() {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
mutableState.write { $0.retryCount += 1 }
reset()
eventMonitor?.requestIsRetrying(self)
}
/// Called to determine whether retry will be triggered for the particular error, or whether the instance should
/// call `finish()`.
///
/// - Parameter error: The possible `AFError` which may trigger retry.
func retryOrFinish(error: AFError?) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
guard !isCancelled, let error, let delegate else { finish(); return }
delegate.retryResult(for: self, dueTo: error) { retryResult in
switch retryResult {
case .doNotRetry:
self.finish()
case let .doNotRetryWithError(retryError):
self.finish(error: retryError.asAFError(orFailWith: "Received retryError was not already AFError"))
case .retry, .retryWithDelay:
delegate.retryRequest(self, withDelay: retryResult.delay)
}
}
}
/// Finishes this `Request` and starts the response serializers.
///
/// - Parameter error: The possible `Error` with which the instance will finish.
func finish(error: AFError? = nil) {
dispatchPrecondition(condition: .onQueue(underlyingQueue))
guard !mutableState.isFinishing else { return }
mutableState.isFinishing = true
if let error { self.error = error }
// Start response handlers
processNextResponseSerializer()
eventMonitor?.requestDidFinish(self)
}
/// Appends the response serialization closure to the instance.
///
/// - Note: This method will also `resume` the instance if `delegate.startImmediately` returns `true`.
///
/// - Parameter closure: The closure containing the response serialization call.
func appendResponseSerializer(_ closure: @escaping () -> Void) {
mutableState.write { mutableState in
mutableState.responseSerializers.append(closure)
if mutableState.state == .finished {
mutableState.state = .resumed
}
if mutableState.responseSerializerProcessingFinished {
underlyingQueue.async { self.processNextResponseSerializer() }
}
if mutableState.state.canTransitionTo(.resumed) {
underlyingQueue.async { if self.delegate?.startImmediately == true { self.resume() } }
}
}
}
/// Returns the next response serializer closure to execute if there's one left.
///
/// - Returns: The next response serialization closure, if there is one.
func nextResponseSerializer() -> (() -> Void)? {
var responseSerializer: (() -> Void)?
mutableState.write { mutableState in
let responseSerializerIndex = mutableState.responseSerializerCompletions.count
if responseSerializerIndex < mutableState.responseSerializers.count {
responseSerializer = mutableState.responseSerializers[responseSerializerIndex]
}
}
return responseSerializer
}
/// Processes the next response serializer and calls all completions if response serialization is complete.
func processNextResponseSerializer() {
guard let responseSerializer = nextResponseSerializer() else {
// Execute all response serializer completions and clear them
var completions: [() -> Void] = []
mutableState.write { mutableState in
completions = mutableState.responseSerializerCompletions
// Clear out all response serializers and response serializer completions in mutable state since the
// request is complete. It's important to do this prior to calling the completion closures in case
// the completions call back into the request triggering a re-processing of the response serializers.
// An example of how this can happen is by calling cancel inside a response completion closure.
mutableState.responseSerializers.removeAll()
mutableState.responseSerializerCompletions.removeAll()
if mutableState.state.canTransitionTo(.finished) {
mutableState.state = .finished
}
mutableState.responseSerializerProcessingFinished = true
mutableState.isFinishing = false
}
completions.forEach { $0() }
// Cleanup the request
cleanup()
return
}
serializationQueue.async { responseSerializer() }
}
/// Notifies the `Request` that the response serializer is complete.
///
/// - Parameter completion: The completion handler provided with the response serializer, called when all serializers
/// are complete.
func responseSerializerDidComplete(completion: @escaping () -> Void) {
mutableState.write { $0.responseSerializerCompletions.append(completion) }
processNextResponseSerializer()
}
/// Resets all task and response serializer related state for retry.
func reset() {
error = nil
uploadProgress.totalUnitCount = 0
uploadProgress.completedUnitCount = 0
downloadProgress.totalUnitCount = 0
downloadProgress.completedUnitCount = 0
mutableState.write { state in
state.isFinishing = false
state.responseSerializerCompletions = []
}
}
/// Called when updating the upload progress.
///
/// - Parameters:
/// - totalBytesSent: Total bytes sent so far.
/// - totalBytesExpectedToSend: Total bytes expected to send.
func updateUploadProgress(totalBytesSent: Int64, totalBytesExpectedToSend: Int64) {
uploadProgress.totalUnitCount = totalBytesExpectedToSend
uploadProgress.completedUnitCount = totalBytesSent
uploadProgressHandler?.queue.async { self.uploadProgressHandler?.handler(self.uploadProgress) }
}
/// Perform a closure on the current `state` while locked.
///
/// - Parameter perform: The closure to perform.
func withState(perform: (State) -> Void) {
mutableState.withState(perform: perform)
}
// MARK: Task Creation
/// Called when creating a `URLSessionTask` for this `Request`. Subclasses must override.
///
/// - Parameters:
/// - request: `URLRequest` to use to create the `URLSessionTask`.
/// - session: `URLSession` which creates the `URLSessionTask`.
///
/// - Returns: The `URLSessionTask` created.
func task(for request: URLRequest, using session: URLSession) -> URLSessionTask {
fatalError("Subclasses must override.")
}
// MARK: - Public API
// These APIs are callable from any queue.
// MARK: State
/// Cancels the instance. Once cancelled, a `Request` can no longer be resumed or suspended.
///
/// - Returns: The instance.
@discardableResult
public func cancel() -> Self {
mutableState.write { mutableState in
guard mutableState.state.canTransitionTo(.cancelled) else { return }
mutableState.state = .cancelled
underlyingQueue.async { self.didCancel() }
guard let task = mutableState.tasks.last, task.state != .completed else {
underlyingQueue.async { self.finish() }
return
}
// Resume to ensure metrics are gathered.
task.resume()
task.cancel()
underlyingQueue.async { self.didCancelTask(task) }
}
return self
}
/// Suspends the instance.
///
/// - Returns: The instance.
@discardableResult
public func suspend() -> Self {
mutableState.write { mutableState in
guard mutableState.state.canTransitionTo(.suspended) else { return }
mutableState.state = .suspended
underlyingQueue.async { self.didSuspend() }
guard let task = mutableState.tasks.last, task.state != .completed else { return }
task.suspend()
underlyingQueue.async { self.didSuspendTask(task) }
}
return self
}
/// Resumes the instance.
///
/// - Returns: The instance.
@discardableResult
public func resume() -> Self {
mutableState.write { mutableState in
guard mutableState.state.canTransitionTo(.resumed) else { return }
mutableState.state = .resumed
underlyingQueue.async { self.didResume() }
guard let task = mutableState.tasks.last, task.state != .completed else { return }
task.resume()
underlyingQueue.async { self.didResumeTask(task) }
}
return self
}
// MARK: - Closure API
/// Associates a credential using the provided values with the instance.
///
/// - Parameters:
/// - username: The username.
/// - password: The password.
/// - persistence: The `URLCredential.Persistence` for the created `URLCredential`. `.forSession` by default.
///
/// - Returns: The instance.
@discardableResult
public func authenticate(username: String, password: String, persistence: URLCredential.Persistence = .forSession) -> Self {
let credential = URLCredential(user: username, password: password, persistence: persistence)
return authenticate(with: credential)
}
/// Associates the provided credential with the instance.
///
/// - Parameter credential: The `URLCredential`.
///
/// - Returns: The instance.
@discardableResult
public func authenticate(with credential: URLCredential) -> Self {
mutableState.credential = credential
return self
}
/// Sets a closure to be called periodically during the lifecycle of the instance as data is read from the server.
///
/// - Note: Only the last closure provided is used.
///
/// - Parameters:
/// - queue: The `DispatchQueue` to execute the closure on. `.main` by default.
/// - closure: The closure to be executed periodically as data is read from the server.
///
/// - Returns: The instance.
@discardableResult
public func downloadProgress(queue: DispatchQueue = .main, closure: @escaping ProgressHandler) -> Self {
mutableState.downloadProgressHandler = (handler: closure, queue: queue)
return self
}
/// Sets a closure to be called periodically during the lifecycle of the instance as data is sent to the server.
///
/// - Note: Only the last closure provided is used.
///
/// - Parameters:
/// - queue: The `DispatchQueue` to execute the closure on. `.main` by default.
/// - closure: The closure to be executed periodically as data is sent to the server.
///
/// - Returns: The instance.
@discardableResult
public func uploadProgress(queue: DispatchQueue = .main, closure: @escaping ProgressHandler) -> Self {
mutableState.uploadProgressHandler = (handler: closure, queue: queue)
return self
}
// MARK: Redirects
/// Sets the redirect handler for the instance which will be used if a redirect response is encountered.
///
/// - Note: Attempting to set the redirect handler more than once is a logic error and will crash.
///
/// - Parameter handler: The `RedirectHandler`.
///
/// - Returns: The instance.
@discardableResult
public func redirect(using handler: RedirectHandler) -> Self {
mutableState.write { mutableState in
precondition(mutableState.redirectHandler == nil, "Redirect handler has already been set.")
mutableState.redirectHandler = handler
}
return self
}
// MARK: Cached Responses
/// Sets the cached response handler for the `Request` which will be used when attempting to cache a response.
///
/// - Note: Attempting to set the cache handler more than once is a logic error and will crash.
///
/// - Parameter handler: The `CachedResponseHandler`.
///
/// - Returns: The instance.
@discardableResult
public func cacheResponse(using handler: CachedResponseHandler) -> Self {
mutableState.write { mutableState in
precondition(mutableState.cachedResponseHandler == nil, "Cached response handler has already been set.")
mutableState.cachedResponseHandler = handler
}
return self
}
// MARK: - Lifetime APIs
/// Sets a handler to be called when the cURL description of the request is available.
///
/// - Note: When waiting for a `Request`'s `URLRequest` to be created, only the last `handler` will be called.
///
/// - Parameters:
/// - queue: `DispatchQueue` on which `handler` will be called.
/// - handler: Closure to be called when the cURL description is available.
///
/// - Returns: The instance.
@discardableResult
public func cURLDescription(on queue: DispatchQueue, calling handler: @escaping (String) -> Void) -> Self {
mutableState.write { mutableState in
if mutableState.requests.last != nil {
queue.async { handler(self.cURLDescription()) }
} else {
mutableState.cURLHandler = (queue, handler)
}
}
return self
}
/// Sets a handler to be called when the cURL description of the request is available.
///
/// - Note: When waiting for a `Request`'s `URLRequest` to be created, only the last `handler` will be called.
///
/// - Parameter handler: Closure to be called when the cURL description is available. Called on the instance's
/// `underlyingQueue` by default.
///
/// - Returns: The instance.
@discardableResult
public func cURLDescription(calling handler: @escaping (String) -> Void) -> Self {
cURLDescription(on: underlyingQueue, calling: handler)
return self
}
/// Sets a closure to called whenever Alamofire creates a `URLRequest` for this instance.
///
/// - Note: This closure will be called multiple times if the instance adapts incoming `URLRequest`s or is retried.
///
/// - Parameters:
/// - queue: `DispatchQueue` on which `handler` will be called. `.main` by default.
/// - handler: Closure to be called when a `URLRequest` is available.
///
/// - Returns: The instance.
@discardableResult
public func onURLRequestCreation(on queue: DispatchQueue = .main, perform handler: @escaping (URLRequest) -> Void) -> Self {
mutableState.write { state in
if let request = state.requests.last {
queue.async { handler(request) }
}
state.urlRequestHandler = (queue, handler)
}
return self
}
/// Sets a closure to be called whenever the instance creates a `URLSessionTask`.
///
/// - Note: This API should only be used to provide `URLSessionTask`s to existing API, like `NSFileProvider`. It
/// **SHOULD NOT** be used to interact with tasks directly, as that may be break Alamofire features.
/// Additionally, this closure may be called multiple times if the instance is retried.
///
/// - Parameters:
/// - queue: `DispatchQueue` on which `handler` will be called. `.main` by default.
/// - handler: Closure to be called when the `URLSessionTask` is available.
///
/// - Returns: The instance.
@discardableResult
public func onURLSessionTaskCreation(on queue: DispatchQueue = .main, perform handler: @escaping (URLSessionTask) -> Void) -> Self {
mutableState.write { state in
if let task = state.tasks.last {
queue.async { handler(task) }
}
state.urlSessionTaskHandler = (queue, handler)
}
return self
}
// MARK: Cleanup
/// Adds a `finishHandler` closure to be called when the request completes.
///
/// - Parameter closure: Closure to be called when the request finishes.
func onFinish(perform finishHandler: @escaping () -> Void) {
guard !isFinished else { finishHandler(); return }
mutableState.write { state in
state.finishHandlers.append(finishHandler)
}
}
/// Final cleanup step executed when the instance finishes response serialization.
func cleanup() {
let handlers = mutableState.finishHandlers
handlers.forEach { $0() }
mutableState.write { state in
state.finishHandlers.removeAll()
}
delegate?.cleanup(after: self)
}
}
extension Request {
/// Type indicating how a `DataRequest` or `DataStreamRequest` should proceed after receiving an `HTTPURLResponse`.
public enum ResponseDisposition {
/// Allow the request to continue normally.
case allow
/// Cancel the request, similar to calling `cancel()`.
case cancel
var sessionDisposition: URLSession.ResponseDisposition {
switch self {
case .allow: return .allow
case .cancel: return .cancel
}
}
}
}
// MARK: - Protocol Conformances
extension Request: Equatable {
public static func ==(lhs: Request, rhs: Request) -> Bool {
lhs.id == rhs.id
}
}
extension Request: Hashable {
public func hash(into hasher: inout Hasher) {
hasher.combine(id)
}
}
extension Request: CustomStringConvertible {
/// A textual representation of this instance, including the `HTTPMethod` and `URL` if the `URLRequest` has been
/// created, as well as the response status code, if a response has been received.
public var description: String {
guard let request = performedRequests.last ?? lastRequest,
let url = request.url,
let method = request.httpMethod else { return "No request created yet." }
let requestDescription = "\(method) \(url.absoluteString)"
return response.map { "\(requestDescription) (\($0.statusCode))" } ?? requestDescription
}
}
extension Request {
/// cURL representation of the instance.
///
/// - Returns: The cURL equivalent of the instance.
public func cURLDescription() -> String {
guard
let request = lastRequest,
let url = request.url,
let host = url.host,
let method = request.httpMethod else { return "$ curl command could not be created" }
var components = ["$ curl -v"]
components.append("-X \(method)")
if let credentialStorage = delegate?.sessionConfiguration.urlCredentialStorage {
let protectionSpace = URLProtectionSpace(host: host,
port: url.port ?? 0,
protocol: url.scheme,
realm: host,
authenticationMethod: NSURLAuthenticationMethodHTTPBasic)
if let credentials = credentialStorage.credentials(for: protectionSpace)?.values {
for credential in credentials {
guard let user = credential.user, let password = credential.password else { continue }
components.append("-u \(user):\(password)")
}
} else {
if let credential, let user = credential.user, let password = credential.password {
components.append("-u \(user):\(password)")
}
}
}
if let configuration = delegate?.sessionConfiguration, configuration.httpShouldSetCookies {
if
let cookieStorage = configuration.httpCookieStorage,
let cookies = cookieStorage.cookies(for: url), !cookies.isEmpty {
let allCookies = cookies.map { "\($0.name)=\($0.value)" }.joined(separator: ";")
components.append("-b \"\(allCookies)\"")
}
}
var headers = HTTPHeaders()
if let sessionHeaders = delegate?.sessionConfiguration.headers {
for header in sessionHeaders where header.name != "Cookie" {
headers[header.name] = header.value
}
}
for header in request.headers where header.name != "Cookie" {
headers[header.name] = header.value
}
for header in headers {
let escapedValue = header.value.replacingOccurrences(of: "\"", with: "\\\"")
components.append("-H \"\(header.name): \(escapedValue)\"")
}
if let httpBodyData = request.httpBody {
let httpBody = String(decoding: httpBodyData, as: UTF8.self)
var escapedBody = httpBody.replacingOccurrences(of: "\\\"", with: "\\\\\"")
escapedBody = escapedBody.replacingOccurrences(of: "\"", with: "\\\"")
components.append("-d \"\(escapedBody)\"")
}
components.append("\"\(url.absoluteString)\"")
return components.joined(separator: " \\\n\t")
}
}
/// Protocol abstraction for `Request`'s communication back to the `SessionDelegate`.
public protocol RequestDelegate: AnyObject {
/// `URLSessionConfiguration` used to create the underlying `URLSessionTask`s.
var sessionConfiguration: URLSessionConfiguration { get }
/// Determines whether the `Request` should automatically call `resume()` when adding the first response handler.
var startImmediately: Bool { get }
/// Notifies the delegate the `Request` has reached a point where it needs cleanup.
///
/// - Parameter request: The `Request` to cleanup after.
func cleanup(after request: Request)
/// Asynchronously ask the delegate whether a `Request` will be retried.
///
/// - Parameters:
/// - request: `Request` which failed.
/// - error: `Error` which produced the failure.
/// - completion: Closure taking the `RetryResult` for evaluation.
func retryResult(for request: Request, dueTo error: AFError, completion: @escaping (RetryResult) -> Void)
/// Asynchronously retry the `Request`.
///
/// - Parameters:
/// - request: `Request` which will be retried.
/// - timeDelay: `TimeInterval` after which the retry will be triggered.
func retryRequest(_ request: Request, withDelay timeDelay: TimeInterval?)
}