iOS网络请求错误代码解析

最近在使用某款 iOS 应用时，发现无论怎么刷新都会遇到错误 -1003。尝试切换到 Wi-Fi 网络后，错误代码变为 -1001。经过一番搜索，了解到这两个错误分别表示“找不到主机”和“请求超时”。为了更好地理解这些错误，我们可以参考苹果官方文档中的错误代码定义。

官方链接为：官方文档链接

以下是 Swift 和 Objective-C 中部分错误代码的定义：

Swift 定义

var NSURLErrorUnknown: Int { get }
var NSURLErrorCancelled: Int { get }
var NSURLErrorBadURL: Int { get }
var NSURLErrorTimedOut: Int { get }
var NSURLErrorUnsupportedURL: Int { get }
var NSURLErrorCannotFindHost: Int { get }
var NSURLErrorCannotConnectToHost: Int { get }
var NSURLErrorDataLengthExceedsMaximum: Int { get }
var NSURLErrorNetworkConnectionLost: Int { get }
var NSURLErrorDNSLookupFailed: Int { get }
var NSURLErrorHTTPTooManyRedirects: Int { get }
var NSURLErrorResourceUnavailable: Int { get }
var NSURLErrorNotConnectedToInternet: Int { get }
var NSURLErrorRedirectToNonExistentLocation: Int { get }
var NSURLErrorBadServerResponse: Int { get }
var NSURLErrorUserCancelledAuthentication: Int { get }
var NSURLErrorUserAuthenticationRequired: Int { get }
var NSURLErrorZeroByteResource: Int { get }
var NSURLErrorCannotDecodeRawData: Int { get }
var NSURLErrorCannotDecodeContentData: Int { get }
var NSURLErrorCannotParseResponse: Int { get }
var NSURLErrorInternationalRoamingOff: Int { get }
var NSURLErrorCallIsActive: Int { get }
var NSURLErrorDataNotAllowed: Int { get }
var NSURLErrorRequestBodyStreamExhausted: Int { get }
var NSURLErrorFileDoesNotExist: Int { get }
var NSURLErrorFileIsDirectory: Int { get }
var NSURLErrorNoPermissionsToReadFile: Int { get }
var NSURLErrorSecureConnectionFailed: Int { get }
var NSURLErrorServerCertificateHasBadDate: Int { get }
var NSURLErrorServerCertificateUntrusted: Int { get }
var NSURLErrorServerCertificateHasUnknownRoot: Int { get }
var NSURLErrorServerCertificateNotYetValid: Int { get }
var NSURLErrorClientCertificateRejected: Int { get }
var NSURLErrorClientCertificateRequired: Int { get }
var NSURLErrorCannotLoadFromNetwork: Int { get }
var NSURLErrorCannotCreateFile: Int { get }
var NSURLErrorCannotOpenFile: Int { get }
var NSURLErrorCannotCloseFile: Int { get }
var NSURLErrorCannotWriteToFile: Int { get }
var NSURLErrorCannotRemoveFile: Int { get }
var NSURLErrorCannotMoveFile: Int { get }
var NSURLErrorDownloadDecodingFailedMidStream: Int { get }
var NSURLErrorDownloadDecodingFailedToComplete: Int { get }

Objective-C 定义

enum {
    NSURLErrorUnknown = -1,
    NSURLErrorCancelled = -999,
    NSURLErrorBadURL = -1000,
    NSURLErrorTimedOut = -1001,
    NSURLErrorUnsupportedURL = -1002,
    NSURLErrorCannotFindHost = -1003,
    NSURLErrorCannotCOnnectToHost= -1004,
    NSURLErrorDataLengthExceedsMaximum = -1103,
    NSURLErrorNetworkCOnnectionLost= -1005,
    NSURLErrorDNSLookupFailed = -1006,
    NSURLErrorHTTPTooManyRedirects = -1007,
    NSURLErrorResourceUnavailable = -1008,
    NSURLErrorNotCOnnectedToInternet= -1009,
    NSURLErrorRedirectTOnonExistentLocation= -1010,
    NSURLErrorBadServerRespOnse= -1011,
    NSURLErrorUserCancelledAuthentication = -1012,
    NSURLErrorUserAuthenticatiOnRequired= -1013,
    NSURLErrorZeroByteResource = -1014,
    NSURLErrorCannotDecodeRawData = -1015,
    NSURLErrorCannotDecodeCOntentData= -1016,
    NSURLErrorCannotParseRespOnse= -1017,
    NSURLErrorInternatiOnalRoamingOff= -1018,
    NSURLErrorCallIsActive = -1019,
    NSURLErrorDataNotAllowed = -1020,
    NSURLErrorRequestBodyStreamExhausted = -1021,
    NSURLErrorFileDoesNotExist = -1100,
    NSURLErrorFileIsDirectory = -1101,
    NSURLErrorNoPermissiOnsToReadFile= -1102,
    NSURLErrorSecureCOnnectionFailed= -1200,
    NSURLErrorServerCertificateHasBadDate = -1201,
    NSURLErrorServerCertificateUntrusted = -1202,
    NSURLErrorServerCertificateHasUnknownRoot = -1203,
    NSURLErrorServerCertificateNotYetValid = -1204,
    NSURLErrorClientCertificateRejected = -1205,
    NSURLErrorClientCertificateRequired = -1206,
    NSURLErrorCannotLoadFromNetwork = -2000,
    NSURLErrorCannotCreateFile = -3000,
    NSURLErrorCannotOpenFile = -3001,
    NSURLErrorCannotCloseFile = -3002,
    NSURLErrorCannotWriteToFile = -3003,
    NSURLErrorCannotRemoveFile = -3004,
    NSURLErrorCannotMoveFile = -3005,
    NSURLErrorDownloadDecodingFailedMidStream = -3006,
    NSURLErrorDownloadDecodingFailedToComplete = -3007
};

通过查阅这些错误代码，我们可以更好地理解应用中遇到的问题，并采取相应的解决措施。例如，错误 -1003 表示 DNS 解析失败，可能是由于网络配置问题或服务器域名解析问题导致的；而错误 -1001 则表示请求超时，可能是由于网络延迟过高或服务器响应慢造成的。