这里面主要写了如何验证请求是否有效。
1. 验证Request
extension Request {
// 为了代码简洁，把ResponseValidationFailureReason定义为ErrorReason
fileprivate typealias ErrorReason = AFError.ResponseValidationFailureReason
// 用于表示验证结果
public enum ValidationResult {
case success
case failure(Error)
}
// MIMEType类型
fileprivate struct MIMEType {
let type: String
let subtype: String
// 是否是通配符
var isWildcard: Bool { return type == "*" && subtype == "*" }
init?(_ string: String) {
let components: [String] = {
let stripped = string.trimmingCharacters(in: .whitespacesAndNewlines)
#if swift(>=3.2)
let split = stripped[..<(stripped.range(of: ";")?.lowerBound ?? stripped.endIndex)]
#else
let split = stripped.substring(to: stripped.range(of: ";")?.lowerBound ?? stripped.endIndex)
#endif
return split.components(separatedBy: "/")
}()
if let type = components.first, let subtype = components.last {
self.type = type
self.subtype = subtype
} else {
return nil
}
}
// 判断与另外一个给定的MIMEType是否匹配
func matches(_ mime: MIMEType) -> Bool {
switch (type, subtype) {
case (mime.type, mime.subtype), (mime.type, "*"), ("*", mime.subtype), ("*", "*"):
return true
default:
return false
}
}
}
// 请求成功的状态码
fileprivate var acceptableStatusCodes: [Int] { return Array(200..<300) }
// 接受的ContentType类型
fileprivate var acceptableContentTypes: [String] {
if let accept = request?.value(forHTTPHeaderField: "Accept") {
return accept.components(separatedBy: ",")
}
return ["*/*"]
}
// 验证响应的状态码是否匹配给定的状态码
fileprivate func validate<S: Sequence>(
statusCode acceptableStatusCodes: S,
response: HTTPURLResponse)
-> ValidationResult
where S.Iterator.Element == Int
{
if acceptableStatusCodes.contains(response.statusCode) {
return .success
} else {
let reason: ErrorReason = .unacceptableStatusCode(code: response.statusCode)
return .failure(AFError.responseValidationFailed(reason: reason))
}
}
// 验证响应的ContentType是否匹配给定ContentTypes
fileprivate func validate<S: Sequence>(
contentType acceptableContentTypes: S,
response: HTTPURLResponse,
data: Data?)
-> ValidationResult
where S.Iterator.Element == String
{
// 如果有数据，说明请求成功了，直接返回
guard let data = data, data.count > 0 else { return .success }
guard
let responseContentType = response.mimeType,
let responseMIMEType = MIMEType(responseContentType)
else { // 响应中没有mimeType
// 如果给定的ContentTypes是通配符，则验证成功
for contentType in acceptableContentTypes {
if let mimeType = MIMEType(contentType), mimeType.isWildcard {
return .success
}
}
let error: AFError = {
let reason: ErrorReason = .missingContentType(acceptableContentTypes: Array(acceptableContentTypes))
return AFError.responseValidationFailed(reason: reason)
}()
return .failure(error)
}
// 如果响应的contentType匹配给定的ContentTypes，则验证成功
for contentType in acceptableContentTypes {
if let acceptableMIMEType = MIMEType(contentType), acceptableMIMEType.matches(responseMIMEType) {
return .success
}
}
let error: AFError = {
let reason: ErrorReason = .unacceptableContentType(
acceptableContentTypes: Array(acceptableContentTypes),
responseContentType: responseContentType
)
return AFError.responseValidationFailed(reason: reason)
}()
return .failure(error)
}
}
2. 验证DataRequest
extension DataRequest {
// 验证请求是否有效的closure
public typealias Validation = (URLRequest?, HTTPURLResponse, Data?) -> ValidationResult
// 使用给定的Validation验证
@discardableResult
public func validate(_ validation: @escaping Validation) -> Self {
let validationExecution: () -> Void = { [unowned self] in
if
let response = self.response,
self.delegate.error == nil,
case let .failure(error) = validation(self.request, response, self.delegate.data)
{
self.delegate.error = error
}
}
// 把验证添加到一个数组中，待请求完成后执行所有验证
validations.append(validationExecution)
return self
}
// 验证响应状态码是否与给定的状态码匹配
@discardableResult
public func validate<S: Sequence>(statusCode acceptableStatusCodes: S) -> Self where S.Iterator.Element == Int {
return validate { [unowned self] _, response, _ in
// 直接调用父类的验证方法
return self.validate(statusCode: acceptableStatusCodes, response: response)
}
}
// 验证响应的contentType是否与给定的contentTypes匹配
@discardableResult
public func validate<S: Sequence>(contentType acceptableContentTypes: S) -> Self where S.Iterator.Element == String {
return validate { [unowned self] _, response, data in
// 直接调用父类的验证方法
return self.validate(contentType: acceptableContentTypes, response: response, data: data)
}
}
// 默认的验证方法：
// 1）验证状态码是否在200...299区间；2）验证contentType是否与请求头中给定的"Accept"相同
@discardableResult
public func validate() -> Self {
return validate(statusCode: self.acceptableStatusCodes).validate(contentType: self.acceptableContentTypes)
}
}
2. 验证DownloadRequest
这里基本上跟验证DataRequest的一样。
extension DownloadRequest {
// 验证请求是否有效的closure
public typealias Validation = (
_ request: URLRequest?,
_ response: HTTPURLResponse,
_ temporaryURL: URL?,
_ destinationURL: URL?)
-> ValidationResult
// 使用给定的Validation验证
@discardableResult
public func validate(_ validation: @escaping Validation) -> Self {
let validationExecution: () -> Void = { [unowned self] in
let request = self.request
let temporaryURL = self.downloadDelegate.temporaryURL
let destinationURL = self.downloadDelegate.destinationURL
if
let response = self.response,
self.delegate.error == nil,
case let .failure(error) = validation(request, response, temporaryURL, destinationURL)
{
self.delegate.error = error
}
}
// 把验证添加到一个数组中，待请求完成后执行所有验证
validations.append(validationExecution)
return self
}
// 验证响应状态码是否与给定的状态码匹配
@discardableResult
public func validate<S: Sequence>(statusCode acceptableStatusCodes: S) -> Self where S.Iterator.Element == Int {
return validate { [unowned self] _, response, _, _ in
// 直接调用父类的验证方法
return self.validate(statusCode: acceptableStatusCodes, response: response)
}
}
// 验证响应的contentType是否与给定的contentTypes匹配
@discardableResult
public func validate<S: Sequence>(contentType acceptableContentTypes: S) -> Self where S.Iterator.Element == String {
return validate { [unowned self] _, response, _, _ in
let fileURL = self.downloadDelegate.fileURL
guard let validFileURL = fileURL else {
return .failure(AFError.responseValidationFailed(reason: .dataFileNil))
}
do {
let data = try Data(contentsOf: validFileURL)
// 直接调用父类的验证方法
return self.validate(contentType: acceptableContentTypes, response: response, data: data)
} catch {
return .failure(AFError.responseValidationFailed(reason: .dataFileReadFailed(at: validFileURL)))
}
}
}
// 默认的验证方法：
// 1）验证状态码是否在200...299区间；2）验证contentType是否与请求头中给定的"Accept"相同
@discardableResult
public func validate() -> Self {
return validate(statusCode: self.acceptableStatusCodes).validate(contentType: self.acceptableContentTypes)
}
}
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