Moya-ModelMapper/Demo/Pods/Alamofire/Source/ResponseSerialization.swift

801 lines
38 KiB
Swift

//
// ResponseSerialization.swift
//
// Copyright (c) 2014-2018 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
// MARK: Protocols
/// The type to which all data response serializers must conform in order to serialize a response.
public protocol DataResponseSerializerProtocol {
/// The type of serialized object to be created.
associatedtype SerializedObject
/// Serialize the response `Data` into the provided type..
///
/// - Parameters:
/// - request: `URLRequest` which was used to perform the request, if any.
/// - response: `HTTPURLResponse` received from the server, if any.
/// - data: `Data` returned from the server, if any.
/// - error: `Error` produced by Alamofire or the underlying `URLSession` during the request.
///
/// - Returns: The `SerializedObject`.
/// - Throws: Any `Error` produced during serialization.
func serialize(request: URLRequest?, response: HTTPURLResponse?, data: Data?, error: Error?) throws -> SerializedObject
}
/// The type to which all download response serializers must conform in order to serialize a response.
public protocol DownloadResponseSerializerProtocol {
/// The type of serialized object to be created.
associatedtype SerializedObject
/// Serialize the downloaded response `Data` from disk into the provided type..
///
/// - Parameters:
/// - request: `URLRequest` which was used to perform the request, if any.
/// - response: `HTTPURLResponse` received from the server, if any.
/// - fileURL: File `URL` to which the response data was downloaded.
/// - error: `Error` produced by Alamofire or the underlying `URLSession` during the request.
///
/// - Returns: The `SerializedObject`.
/// - Throws: Any `Error` produced during serialization.
func serializeDownload(request: URLRequest?, response: HTTPURLResponse?, fileURL: URL?, error: Error?) throws -> SerializedObject
}
/// A serializer that can handle both data and download responses.
public protocol ResponseSerializer: DataResponseSerializerProtocol & DownloadResponseSerializerProtocol {
/// `DataPreprocessor` used to prepare incoming `Data` for serialization.
var dataPreprocessor: DataPreprocessor { get }
/// `HTTPMethod`s for which empty response bodies are considered appropriate.
var emptyRequestMethods: Set<HTTPMethod> { get }
/// HTTP response codes for which empty response bodies are considered appropriate.
var emptyResponseCodes: Set<Int> { get }
}
/// Type used to preprocess `Data` before it handled by a serializer.
public protocol DataPreprocessor {
/// Process `Data` before it's handled by a serializer.
/// - Parameter data: The raw `Data` to process.
func preprocess(_ data: Data) throws -> Data
}
/// `DataPreprocessor` that returns passed `Data` without any transform.
public struct PassthroughPreprocessor: DataPreprocessor {
public init() {}
public func preprocess(_ data: Data) throws -> Data { return data }
}
/// `DataPreprocessor` that trims Google's typical `)]}',\n` XSSI JSON header.
public struct GoogleXSSIPreprocessor: DataPreprocessor {
public init() {}
public func preprocess(_ data: Data) throws -> Data {
return (data.prefix(6) == Data(")]}',\n".utf8)) ? data.dropFirst(6) : data
}
}
extension ResponseSerializer {
/// Default `DataPreprocessor`. `PassthroughPreprocessor` by default.
public static var defaultDataPreprocessor: DataPreprocessor { return PassthroughPreprocessor() }
/// Default `HTTPMethod`s for which empty response bodies are considered appropriate. `[.head]` by default.
public static var defaultEmptyRequestMethods: Set<HTTPMethod> { return [.head] }
/// HTTP response codes for which empty response bodies are considered appropriate. `[204, 205]` by default.
public static var defaultEmptyResponseCodes: Set<Int> { return [204, 205] }
public var dataPreprocessor: DataPreprocessor { return Self.defaultDataPreprocessor }
public var emptyRequestMethods: Set<HTTPMethod> { return Self.defaultEmptyRequestMethods }
public var emptyResponseCodes: Set<Int> { return Self.defaultEmptyResponseCodes }
/// Determines whether the `request` allows empty response bodies, if `request` exists.
///
/// - Parameter request: `URLRequest` to evaluate.
///
/// - Returns: `Bool` representing the outcome of the evaluation, or `nil` if `request` was `nil`.
public func requestAllowsEmptyResponseData(_ request: URLRequest?) -> Bool? {
return request.flatMap { $0.httpMethod }
.flatMap(HTTPMethod.init)
.map { emptyRequestMethods.contains($0) }
}
/// Determines whether the `response` allows empty response bodies, if `response` exists`.
///
/// - Parameter response: `HTTPURLResponse` to evaluate.
///
/// - Returns: `Bool` representing the outcome of the evaluation, or `nil` if `response` was `nil`.
public func responseAllowsEmptyResponseData(_ response: HTTPURLResponse?) -> Bool? {
return response.flatMap { $0.statusCode }
.map { emptyResponseCodes.contains($0) }
}
/// Determines whether `request` and `response` allow empty response bodies.
///
/// - Parameters:
/// - request: `URLRequest` to evaluate.
/// - response: `HTTPURLResponse` to evaluate.
///
/// - Returns: `true` if `request` or `response` allow empty bodies, `false` otherwise.
public func emptyResponseAllowed(forRequest request: URLRequest?, response: HTTPURLResponse?) -> Bool {
return (requestAllowsEmptyResponseData(request) == true) || (responseAllowsEmptyResponseData(response) == true)
}
}
/// By default, any serializer declared to conform to both types will get file serialization for free, as it just feeds
/// the data read from disk into the data response serializer.
public extension DownloadResponseSerializerProtocol where Self: DataResponseSerializerProtocol {
func serializeDownload(request: URLRequest?, response: HTTPURLResponse?, fileURL: URL?, error: Error?) throws -> Self.SerializedObject {
guard error == nil else { throw error! }
guard let fileURL = fileURL else {
throw AFError.responseSerializationFailed(reason: .inputFileNil)
}
let data: Data
do {
data = try Data(contentsOf: fileURL)
} catch {
throw AFError.responseSerializationFailed(reason: .inputFileReadFailed(at: fileURL))
}
do {
return try serialize(request: request, response: response, data: data, error: error)
} catch {
throw error
}
}
}
// MARK: - Default
extension DataRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - completionHandler: The code to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func response(queue: DispatchQueue = .main, completionHandler: @escaping (AFDataResponse<Data?>) -> Void) -> Self {
appendResponseSerializer {
// Start work that should be on the serialization queue.
let result = AFResult<Data?>(value: self.data, error: self.error)
// End work that should be on the serialization queue.
self.underlyingQueue.async {
let response = DataResponse(request: self.request,
response: self.response,
data: self.data,
metrics: self.metrics,
serializationDuration: 0,
result: result)
self.eventMonitor?.request(self, didParseResponse: response)
self.responseSerializerDidComplete { queue.async { completionHandler(response) } }
}
}
return self
}
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default
/// - responseSerializer: The response serializer responsible for serializing the request, response, and data.
/// - completionHandler: The code to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func response<Serializer: DataResponseSerializerProtocol>(queue: DispatchQueue = .main,
responseSerializer: Serializer,
completionHandler: @escaping (AFDataResponse<Serializer.SerializedObject>) -> Void)
-> Self {
appendResponseSerializer {
// Start work that should be on the serialization queue.
let start = CFAbsoluteTimeGetCurrent()
let result: AFResult<Serializer.SerializedObject> = Result {
try responseSerializer.serialize(request: self.request,
response: self.response,
data: self.data,
error: self.error)
}.mapError { error in
error.asAFError(or: .responseSerializationFailed(reason: .customSerializationFailed(error: error)))
}
let end = CFAbsoluteTimeGetCurrent()
// End work that should be on the serialization queue.
self.underlyingQueue.async {
let response = DataResponse(request: self.request,
response: self.response,
data: self.data,
metrics: self.metrics,
serializationDuration: end - start,
result: result)
self.eventMonitor?.request(self, didParseResponse: response)
guard let serializerError = result.failure, let delegate = self.delegate else {
self.responseSerializerDidComplete { queue.async { completionHandler(response) } }
return
}
delegate.retryResult(for: self, dueTo: serializerError) { retryResult in
var didComplete: (() -> Void)?
defer {
if let didComplete = didComplete {
self.responseSerializerDidComplete { queue.async { didComplete() } }
}
}
switch retryResult {
case .doNotRetry:
didComplete = { completionHandler(response) }
case let .doNotRetryWithError(retryError):
let result: AFResult<Serializer.SerializedObject> = .failure(retryError.asAFError(orFailWith: "Received retryError was not already AFError"))
let response = DataResponse(request: self.request,
response: self.response,
data: self.data,
metrics: self.metrics,
serializationDuration: end - start,
result: result)
didComplete = { completionHandler(response) }
case .retry, .retryWithDelay:
delegate.retryRequest(self, withDelay: retryResult.delay)
}
}
}
}
return self
}
}
extension DownloadRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - completionHandler: The code to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func response(queue: DispatchQueue = .main,
completionHandler: @escaping (AFDownloadResponse<URL?>) -> Void)
-> Self {
appendResponseSerializer {
// Start work that should be on the serialization queue.
let result = AFResult<URL?>(value: self.fileURL, error: self.error)
// End work that should be on the serialization queue.
self.underlyingQueue.async {
let response = DownloadResponse(request: self.request,
response: self.response,
fileURL: self.fileURL,
resumeData: self.resumeData,
metrics: self.metrics,
serializationDuration: 0,
result: result)
self.eventMonitor?.request(self, didParseResponse: response)
self.responseSerializerDidComplete { queue.async { completionHandler(response) } }
}
}
return self
}
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - responseSerializer: The response serializer responsible for serializing the request, response, and data
/// contained in the destination `URL`.
/// - completionHandler: The code to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func response<Serializer: DownloadResponseSerializerProtocol>(queue: DispatchQueue = .main,
responseSerializer: Serializer,
completionHandler: @escaping (AFDownloadResponse<Serializer.SerializedObject>) -> Void)
-> Self {
appendResponseSerializer {
// Start work that should be on the serialization queue.
let start = CFAbsoluteTimeGetCurrent()
let result: AFResult<Serializer.SerializedObject> = Result {
try responseSerializer.serializeDownload(request: self.request,
response: self.response,
fileURL: self.fileURL,
error: self.error)
}.mapError { error in
error.asAFError(or: .responseSerializationFailed(reason: .customSerializationFailed(error: error)))
}
let end = CFAbsoluteTimeGetCurrent()
// End work that should be on the serialization queue.
self.underlyingQueue.async {
let response = DownloadResponse(request: self.request,
response: self.response,
fileURL: self.fileURL,
resumeData: self.resumeData,
metrics: self.metrics,
serializationDuration: end - start,
result: result)
self.eventMonitor?.request(self, didParseResponse: response)
guard let serializerError = result.failure, let delegate = self.delegate else {
self.responseSerializerDidComplete { queue.async { completionHandler(response) } }
return
}
delegate.retryResult(for: self, dueTo: serializerError) { retryResult in
var didComplete: (() -> Void)?
defer {
if let didComplete = didComplete {
self.responseSerializerDidComplete { queue.async { didComplete() } }
}
}
switch retryResult {
case .doNotRetry:
didComplete = { completionHandler(response) }
case let .doNotRetryWithError(retryError):
let result: AFResult<Serializer.SerializedObject> = .failure(retryError.asAFError(orFailWith: "Received retryError was not already AFError"))
let response = DownloadResponse(request: self.request,
response: self.response,
fileURL: self.fileURL,
resumeData: self.resumeData,
metrics: self.metrics,
serializationDuration: end - start,
result: result)
didComplete = { completionHandler(response) }
case .retry, .retryWithDelay:
delegate.retryRequest(self, withDelay: retryResult.delay)
}
}
}
}
return self
}
}
// MARK: - Data
extension DataRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - completionHandler: The code to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func responseData(queue: DispatchQueue = .main,
completionHandler: @escaping (AFDataResponse<Data>) -> Void)
-> Self {
return response(queue: queue,
responseSerializer: DataResponseSerializer(),
completionHandler: completionHandler)
}
}
/// A `ResponseSerializer` that performs minimal response checking and returns any response data as-is. By default, a
/// request returning `nil` or no data is considered an error. However, if the response is has a status code valid for
/// empty responses (`204`, `205`), then an empty `Data` value is returned.
public final class DataResponseSerializer: ResponseSerializer {
public let dataPreprocessor: DataPreprocessor
public let emptyResponseCodes: Set<Int>
public let emptyRequestMethods: Set<HTTPMethod>
/// Creates an instance using the provided values.
///
/// - Parameters:
/// - dataPreprocessor: `DataPreprocessor` used to prepare the received `Data` for serialization.
/// - emptyResponseCodes: The HTTP response codes for which empty responses are allowed. `[204, 205]` by default.
/// - emptyRequestMethods: The HTTP request methods for which empty responses are allowed. `[.head]` by default.
public init(dataPreprocessor: DataPreprocessor = DataResponseSerializer.defaultDataPreprocessor,
emptyResponseCodes: Set<Int> = DataResponseSerializer.defaultEmptyResponseCodes,
emptyRequestMethods: Set<HTTPMethod> = DataResponseSerializer.defaultEmptyRequestMethods) {
self.dataPreprocessor = dataPreprocessor
self.emptyResponseCodes = emptyResponseCodes
self.emptyRequestMethods = emptyRequestMethods
}
public func serialize(request: URLRequest?, response: HTTPURLResponse?, data: Data?, error: Error?) throws -> Data {
guard error == nil else { throw error! }
guard var data = data, !data.isEmpty else {
guard emptyResponseAllowed(forRequest: request, response: response) else {
throw AFError.responseSerializationFailed(reason: .inputDataNilOrZeroLength)
}
return Data()
}
data = try dataPreprocessor.preprocess(data)
return data
}
}
extension DownloadRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - completionHandler: The code to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func responseData(queue: DispatchQueue = .main,
completionHandler: @escaping (AFDownloadResponse<Data>) -> Void)
-> Self {
return response(queue: queue,
responseSerializer: DataResponseSerializer(),
completionHandler: completionHandler)
}
}
// MARK: - String
/// A `ResponseSerializer` that decodes the response data as a `String`. By default, a request returning `nil` or no
/// data is considered an error. However, if the response is has a status code valid for empty responses (`204`, `205`),
/// then an empty `String` is returned.
public final class StringResponseSerializer: ResponseSerializer {
public let dataPreprocessor: DataPreprocessor
/// Optional string encoding used to validate the response.
public let encoding: String.Encoding?
public let emptyResponseCodes: Set<Int>
public let emptyRequestMethods: Set<HTTPMethod>
/// Creates an instance with the provided values.
///
/// - Parameters:
/// - dataPreprocessor: `DataPreprocessor` used to prepare the received `Data` for serialization.
/// - encoding: A string encoding. Defaults to `nil`, in which case the encoding will be determined
/// from the server response, falling back to the default HTTP character set, `ISO-8859-1`.
/// - emptyResponseCodes: The HTTP response codes for which empty responses are allowed. `[204, 205]` by default.
/// - emptyRequestMethods: The HTTP request methods for which empty responses are allowed. `[.head]` by default.
public init(dataPreprocessor: DataPreprocessor = StringResponseSerializer.defaultDataPreprocessor,
encoding: String.Encoding? = nil,
emptyResponseCodes: Set<Int> = StringResponseSerializer.defaultEmptyResponseCodes,
emptyRequestMethods: Set<HTTPMethod> = StringResponseSerializer.defaultEmptyRequestMethods) {
self.dataPreprocessor = dataPreprocessor
self.encoding = encoding
self.emptyResponseCodes = emptyResponseCodes
self.emptyRequestMethods = emptyRequestMethods
}
public func serialize(request: URLRequest?, response: HTTPURLResponse?, data: Data?, error: Error?) throws -> String {
guard error == nil else { throw error! }
guard var data = data, !data.isEmpty else {
guard emptyResponseAllowed(forRequest: request, response: response) else {
throw AFError.responseSerializationFailed(reason: .inputDataNilOrZeroLength)
}
return ""
}
data = try dataPreprocessor.preprocess(data)
var convertedEncoding = encoding
if let encodingName = response?.textEncodingName as CFString?, convertedEncoding == nil {
let ianaCharSet = CFStringConvertIANACharSetNameToEncoding(encodingName)
let nsStringEncoding = CFStringConvertEncodingToNSStringEncoding(ianaCharSet)
convertedEncoding = String.Encoding(rawValue: nsStringEncoding)
}
let actualEncoding = convertedEncoding ?? .isoLatin1
guard let string = String(data: data, encoding: actualEncoding) else {
throw AFError.responseSerializationFailed(reason: .stringSerializationFailed(encoding: actualEncoding))
}
return string
}
}
extension DataRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - encoding: The string encoding. Defaults to `nil`, in which case the encoding will be determined from
/// the server response, falling back to the default HTTP character set, `ISO-8859-1`.
/// - completionHandler: A closure to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func responseString(queue: DispatchQueue = .main,
encoding: String.Encoding? = nil,
completionHandler: @escaping (AFDataResponse<String>) -> Void) -> Self {
return response(queue: queue,
responseSerializer: StringResponseSerializer(encoding: encoding),
completionHandler: completionHandler)
}
}
extension DownloadRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - encoding: The string encoding. Defaults to `nil`, in which case the encoding will be determined from
/// the server response, falling back to the default HTTP character set, `ISO-8859-1`.
/// - completionHandler: A closure to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func responseString(queue: DispatchQueue = .main,
encoding: String.Encoding? = nil,
completionHandler: @escaping (AFDownloadResponse<String>) -> Void)
-> Self {
return response(queue: queue,
responseSerializer: StringResponseSerializer(encoding: encoding),
completionHandler: completionHandler)
}
}
// MARK: - JSON
/// A `ResponseSerializer` that decodes the response data using `JSONSerialization`. By default, a request returning
/// `nil` or no data is considered an error. However, if the response is has a status code valid for empty responses
/// (`204`, `205`), then an `NSNull` value is returned.
public final class JSONResponseSerializer: ResponseSerializer {
public let dataPreprocessor: DataPreprocessor
public let emptyResponseCodes: Set<Int>
public let emptyRequestMethods: Set<HTTPMethod>
/// `JSONSerialization.ReadingOptions` used when serializing a response.
public let options: JSONSerialization.ReadingOptions
/// Creates an instance with the provided values.
///
/// - Parameters:
/// - dataPreprocessor: `DataPreprocessor` used to prepare the received `Data` for serialization.
/// - emptyResponseCodes: The HTTP response codes for which empty responses are allowed. `[204, 205]` by default.
/// - emptyRequestMethods: The HTTP request methods for which empty responses are allowed. `[.head]` by default.
/// - options: The options to use. `.allowFragments` by default.
public init(dataPreprocessor: DataPreprocessor = JSONResponseSerializer.defaultDataPreprocessor,
emptyResponseCodes: Set<Int> = JSONResponseSerializer.defaultEmptyResponseCodes,
emptyRequestMethods: Set<HTTPMethod> = JSONResponseSerializer.defaultEmptyRequestMethods,
options: JSONSerialization.ReadingOptions = .allowFragments) {
self.dataPreprocessor = dataPreprocessor
self.emptyResponseCodes = emptyResponseCodes
self.emptyRequestMethods = emptyRequestMethods
self.options = options
}
public func serialize(request: URLRequest?, response: HTTPURLResponse?, data: Data?, error: Error?) throws -> Any {
guard error == nil else { throw error! }
guard var data = data, !data.isEmpty else {
guard emptyResponseAllowed(forRequest: request, response: response) else {
throw AFError.responseSerializationFailed(reason: .inputDataNilOrZeroLength)
}
return NSNull()
}
data = try dataPreprocessor.preprocess(data)
do {
return try JSONSerialization.jsonObject(with: data, options: options)
} catch {
throw AFError.responseSerializationFailed(reason: .jsonSerializationFailed(error: error))
}
}
}
extension DataRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - options: The JSON serialization reading options. `.allowFragments` by default.
/// - completionHandler: A closure to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func responseJSON(queue: DispatchQueue = .main,
options: JSONSerialization.ReadingOptions = .allowFragments,
completionHandler: @escaping (AFDataResponse<Any>) -> Void) -> Self {
return response(queue: queue,
responseSerializer: JSONResponseSerializer(options: options),
completionHandler: completionHandler)
}
}
extension DownloadRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - options: The JSON serialization reading options. `.allowFragments` by default.
/// - completionHandler: A closure to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func responseJSON(queue: DispatchQueue = .main,
options: JSONSerialization.ReadingOptions = .allowFragments,
completionHandler: @escaping (AFDownloadResponse<Any>) -> Void)
-> Self {
return response(queue: queue,
responseSerializer: JSONResponseSerializer(options: options),
completionHandler: completionHandler)
}
}
// MARK: - Empty
/// Protocol representing an empty response. Use `T.emptyValue()` to get an instance.
public protocol EmptyResponse {
/// Empty value for the conforming type.
///
/// - Returns: Value of `Self` to use for empty values.
static func emptyValue() -> Self
}
/// Type representing an empty response. Use `Empty.value` to get the static instance.
public struct Empty: Decodable {
/// Static `Empty` instance used for all `Empty` responses.
public static let value = Empty()
}
extension Empty: EmptyResponse {
public static func emptyValue() -> Empty {
return value
}
}
// MARK: - DataDecoder Protocol
/// Any type which can decode `Data` into a `Decodable` type.
public protocol DataDecoder {
/// Decode `Data` into the provided type.
///
/// - Parameters:
/// - type: The `Type` to be decoded.
/// - data: The `Data` to be decoded.
///
/// - Returns: The decoded value of type `D`.
/// - Throws: Any error that occurs during decode.
func decode<D: Decodable>(_ type: D.Type, from data: Data) throws -> D
}
/// `JSONDecoder` automatically conforms to `DataDecoder`.
extension JSONDecoder: DataDecoder {}
// MARK: - Decodable
/// A `ResponseSerializer` that decodes the response data as a generic value using any type that conforms to
/// `DataDecoder`. By default, this is an instance of `JSONDecoder`. Additionally, a request returning `nil` or no data
/// is considered an error. However, if the response is has a status code valid for empty responses (`204`, `205`), then
/// the `Empty.value` value is returned.
public final class DecodableResponseSerializer<T: Decodable>: ResponseSerializer {
public let dataPreprocessor: DataPreprocessor
/// The `DataDecoder` instance used to decode responses.
public let decoder: DataDecoder
public let emptyResponseCodes: Set<Int>
public let emptyRequestMethods: Set<HTTPMethod>
/// Creates an instance using the values provided.
///
/// - Parameters:
/// - dataPreprocessor: `DataPreprocessor` used to prepare the received `Data` for serialization.
/// - decoder: The `DataDecoder`. `JSONDecoder()` by default.
/// - emptyResponseCodes: The HTTP response codes for which empty responses are allowed. `[204, 205]` by default.
/// - emptyRequestMethods: The HTTP request methods for which empty responses are allowed. `[.head]` by default.
public init(dataPreprocessor: DataPreprocessor = DecodableResponseSerializer.defaultDataPreprocessor,
decoder: DataDecoder = JSONDecoder(),
emptyResponseCodes: Set<Int> = DecodableResponseSerializer.defaultEmptyResponseCodes,
emptyRequestMethods: Set<HTTPMethod> = DecodableResponseSerializer.defaultEmptyRequestMethods) {
self.dataPreprocessor = dataPreprocessor
self.decoder = decoder
self.emptyResponseCodes = emptyResponseCodes
self.emptyRequestMethods = emptyRequestMethods
}
public func serialize(request: URLRequest?, response: HTTPURLResponse?, data: Data?, error: Error?) throws -> T {
guard error == nil else { throw error! }
guard var data = data, !data.isEmpty else {
guard emptyResponseAllowed(forRequest: request, response: response) else {
throw AFError.responseSerializationFailed(reason: .inputDataNilOrZeroLength)
}
guard let emptyResponseType = T.self as? EmptyResponse.Type, let emptyValue = emptyResponseType.emptyValue() as? T else {
throw AFError.responseSerializationFailed(reason: .invalidEmptyResponse(type: "\(T.self)"))
}
return emptyValue
}
data = try dataPreprocessor.preprocess(data)
do {
return try decoder.decode(T.self, from: data)
} catch {
throw AFError.responseSerializationFailed(reason: .decodingFailed(error: error))
}
}
}
extension DataRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - type: `Decodable` type to decode from response data.
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - decoder: `DataDecoder` to use to decode the response. `JSONDecoder()` by default.
/// - completionHandler: A closure to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func responseDecodable<T: Decodable>(of type: T.Type = T.self,
queue: DispatchQueue = .main,
decoder: DataDecoder = JSONDecoder(),
completionHandler: @escaping (AFDataResponse<T>) -> Void) -> Self {
return response(queue: queue,
responseSerializer: DecodableResponseSerializer(decoder: decoder),
completionHandler: completionHandler)
}
}
extension DownloadRequest {
/// Adds a handler to be called once the request has finished.
///
/// - Parameters:
/// - type: `Decodable` type to decode from response data.
/// - queue: The queue on which the completion handler is dispatched. `.main` by default.
/// - decoder: `DataDecoder` to use to decode the response. `JSONDecoder()` by default.
/// - completionHandler: A closure to be executed once the request has finished.
///
/// - Returns: The request.
@discardableResult
public func responseDecodable<T: Decodable>(of type: T.Type = T.self,
queue: DispatchQueue = .main,
decoder: DataDecoder = JSONDecoder(),
completionHandler: @escaping (AFDownloadResponse<T>) -> Void) -> Self {
return response(queue: queue,
responseSerializer: DecodableResponseSerializer(decoder: decoder),
completionHandler: completionHandler)
}
}