无法使用 URLSession 捕获 "Time out" 错误

Question

我正在使用 URLSession 来“POST”请求，但有时在路上请求时我会收到错误代码，错误代码不同，更常见的是：“超时” 这是我在控制台中看到的错误消息示例“Error Domain=NSURLErrorDomain Code=-1009”The Internet connection appears to be offline.“

但是我无法在代码中捕捉到这个错误，我做错了什么？，我也遇到了另一个代码错误，但它并没有改变情况。

错误信息：

2020-11-25 09:52:07.456207+0200 TestApp[40176:2305710] Connection 4: received failure notification
2020-11-25 09:52:07.456344+0200 TestApp[40176:2305710] Connection 4: failed to connect 1:50, reason -1
2020-11-25 09:52:07.456771+0200 TestApp[40176:2305710] Connection 4: encountered error(1:50)
2020-11-25 09:52:07.459696+0200 TestApp[40176:2305710] Task <888AA895-677A-403B-A436-599FF55DB3BB>.<1> HTTP load failed, 0/0 bytes (error code: -1009 [1:50])
2020-11-25 09:52:07.460557+0200 Venom[40176:2305710] Task <888AA895-677A-403B-A436-599FF55DB3BB>.<1> finished with error [-1009] 
Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." UserInfo={_kCFStreamErrorCodeKey=50, NSUnderlyingError=0x600000116880 
{Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_kCFStreamErrorCodeKey=50, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask 
<888AA895-677A-403B-A436-599FF55DB3BB>.<1>, _NSURLErrorRelatedURLSessionTaskErrorKey=(
                "LocalDataTask <888AA895-677A-403B-A436-599FF55DB3BB>.<1>"
            ), NSLocalizedDescription=The Internet connection appears to be offline., 
NSErrorFailingURLStringKey=https://link_to_my_request, NSErrorFailingURLKey=https://link_to_my_request, _kCFStreamErrorDomainKey=1}

我的代码：

func addPlayer(playerCode: String, completion: @escaping (Error?) -> ()) {
    guard let url = URL(string: "\(url)") else { return }

var urlRequest = URLRequest(url: url)
urlRequest.httpMethod = "POST"

let playerCode = [playerCode]

let params = ["players": playerCode]
do {
    let data = try JSONSerialization.data(withJSONObject: params, options: .init())
    
    urlRequest.httpBody = data
    urlRequest.setValue("application/json", forHTTPHeaderField: "content-type")
    
    let sessionConfig = URLSessionConfiguration.default
    sessionConfig.timeoutIntervalForRequest = 5.0
    
    DispatchQueue.global(qos: .background).async {
    URLSession(configuration: sessionConfig).dataTask(with: urlRequest) { (data, resp, err) in

        guard let data = data else { return }
        guard let resp = resp else { return }

        print(data)
        print(resp)

if (err as? URLError)?.code == .timedOut {
                    // Handle session timeout
// THIS PIACE OF CODE DOES NOT EXECUTED
                    print("Oops, what is going on")
                }
        
        guard let response = resp as? HTTPURLResponse, (200 ..< 530) ~= response.statusCode else {
            print("Error: HTTP request failed")
            return
        }
        
        if response.statusCode == 200 {
            print("Status code is 200")
            do {
                let json = try JSONDecoder().decode(ListOfPlayers.self, from: data)

                // I am do what I am want

            
            } catch let jsonError {
                print("Error json serialization \(jsonError)")
            }
            
                completion(nil)
        } else if response.statusCode == 422 {
            print("Status code is 422")
                completion(nil)
            return
        }

}.resume()
}
} catch {
}
}

Answer 1

打印所有可能的 URLError 代码的 rawValue：

unknown: -1
cancelled: -999
badURL: -1000
timedOut: -1001
unsupportedURL: -1002
cannotFindHost: -1003
cannotConnectToHost: -1004
networkConnectionLost: -1005
dnsLookupFailed: -1006
httpTooManyRedirects: -1007
resourceUnavailable: -1008
notConnectedToInternet: -1009
redirectToNonExistentLocation: -1010
badServerResponse: -1011
userCancelledAuthentication: -1012
userAuthenticationRequired: -1013
zeroByteResource: -1014
cannotDecodeRawData: -1015
cannotDecodeContentData: -1016
cannotParseResponse: -1017
appTransportSecurityRequiresSecureConnection: -1022
fileDoesNotExist: -1100
fileIsDirectory: -1101
noPermissionsToReadFile: -1102
dataLengthExceedsMaximum: -1103
secureConnectionFailed: -1200
serverCertificateHasBadDate: -1201
serverCertificateUntrusted: -1202
serverCertificateHasUnknownRoot: -1203
serverCertificateNotYetValid: -1204
clientCertificateRejected: -1205
clientCertificateRequired: -1206
cannotLoadFromNetwork: -2000
cannotCreateFile: -3000
cannotOpenFile: -3001
cannotCloseFile: -3002
cannotWriteToFile: -3003
cannotRemoveFile: -3004
cannotMoveFile: -3005
downloadDecodingFailedMidStream: -3006
downloadDecodingFailedToComplete: -3007
internationalRoamingOff: -1018
callIsActive: -1019
dataNotAllowed: -1020
requestBodyStreamExhausted: -1021
backgroundSessionRequiresSharedContainer: -995
backgroundSessionInUseByAnotherProcess: -996
backgroundSessionWasDisconnected: -997

您可以看到您正在寻找 notConnectedToInternet 代码。（原始值 -1009 的那个）

因此，您的代码可能如下所示：

switch (err as? URLError)?.code {
case .some(.timedOut):
    // Handle session timeout
case .some(.notConnectedToInternet):
    // Handle not connected to internet
default: break
}

无法使用 URLSession 捕获 "Time out" 错误

Can't catch "Time out" error using URLSession

timeout

request

ios

swift

urlsession