NSURLErrorDomain error codes description

Question

This is my first experience of developing an ios app. I am trying to Post some data using Facebook graph api. I am constantly getting the following error:

The operation couldn’t be completed. (NSURLErrorDomain error 400.) 

I cannot able to find the description of NSURLErrorDomain error codes. What does the 400 error code means ?

Answer 1

The NSURLErrorDomain error codes are listed here https://developer.apple.com/documentation/foundation/1508628-url_loading_system_error_codes

However, 400 is just the http status code (http://www.w3.org/Protocols/HTTP/HTRESP.html) being returned which means you've got something wrong with your request.

Answer 2

I was unable to find name of an error for given code when developing in Swift. For that reason I paste minus codes for NSURLErrorDomain taken from NSURLError.h

/*!     @enum NSURL-related Error Codes     @abstract Constants used by NSError to indicate errors in the NSURL domain */ NS_ENUM(NSInteger) {     NSURLErrorUnknown =             -1,     NSURLErrorCancelled =           -999,     NSURLErrorBadURL =              -1000,     NSURLErrorTimedOut =            -1001,     NSURLErrorUnsupportedURL =          -1002,     NSURLErrorCannotFindHost =          -1003,     NSURLErrorCannotConnectToHost =         -1004,     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,     NSURLErrorAppTransportSecurityRequiresSecureConnection NS_ENUM_AVAILABLE(10_11, 9_0) = -1022,     NSURLErrorFileDoesNotExist =        -1100,     NSURLErrorFileIsDirectory =         -1101,     NSURLErrorNoPermissionsToReadFile =     -1102,     NSURLErrorDataLengthExceedsMaximum NS_ENUM_AVAILABLE(10_5, 2_0) =   -1103,      // SSL errors     NSURLErrorSecureConnectionFailed =      -1200,     NSURLErrorServerCertificateHasBadDate =     -1201,     NSURLErrorServerCertificateUntrusted =  -1202,     NSURLErrorServerCertificateHasUnknownRoot = -1203,     NSURLErrorServerCertificateNotYetValid =    -1204,     NSURLErrorClientCertificateRejected =   -1205,     NSURLErrorClientCertificateRequired =   -1206,     NSURLErrorCannotLoadFromNetwork =       -2000,      // Download and file I/O errors     NSURLErrorCannotCreateFile =        -3000,     NSURLErrorCannotOpenFile =          -3001,     NSURLErrorCannotCloseFile =         -3002,     NSURLErrorCannotWriteToFile =       -3003,     NSURLErrorCannotRemoveFile =        -3004,     NSURLErrorCannotMoveFile =          -3005,     NSURLErrorDownloadDecodingFailedMidStream = -3006,     NSURLErrorDownloadDecodingFailedToComplete =-3007,      NSURLErrorInternationalRoamingOff NS_ENUM_AVAILABLE(10_7, 3_0) =         -1018,     NSURLErrorCallIsActive NS_ENUM_AVAILABLE(10_7, 3_0) =                    -1019,     NSURLErrorDataNotAllowed NS_ENUM_AVAILABLE(10_7, 3_0) =                  -1020,     NSURLErrorRequestBodyStreamExhausted NS_ENUM_AVAILABLE(10_7, 3_0) =      -1021,      NSURLErrorBackgroundSessionRequiresSharedContainer NS_ENUM_AVAILABLE(10_10, 8_0) = -995,     NSURLErrorBackgroundSessionInUseByAnotherProcess NS_ENUM_AVAILABLE(10_10, 8_0) = -996,     NSURLErrorBackgroundSessionWasDisconnected NS_ENUM_AVAILABLE(10_10, 8_0)= -997, };