Error codes returned by URL loading APIs.


These error codes are for NSError objects in the domain NSURLErrorDomain.


Error Details

var errorCode: Int

The error code within the domain.

var errorUserInfo: [String : Any]

The error’s user-info dictionary.

var failingURL: URL?

The URL which caused a load to fail.

var failureURLPeerTrust: SecTrust?

The state of a failed SSL handshake.

var failureURLString: String?

The string for the URL which caused a load to fail.

Error Domain

static var errorDomain: String

The domain of the URL error.

Error Codes

static var appTransportSecurityRequiresSecureConnection: URLError.Code

App Transport Security disallowed a connection because there is no secure network connection.

static var backgroundSessionInUseByAnotherProcess: URLError.Code

An app or app extension attempted to connect to a background session that is already connected to a process.

static var backgroundSessionRequiresSharedContainer: URLError.Code

The shared container identifier of the URL session configuration is needed but has not been set.

static var backgroundSessionWasDisconnected: URLError.Code

The app is suspended or exits while a background data task is processing.

static var badServerResponse: URLError.Code

The URL Loading system received bad data from the server.

static var badURL: URLError.Code

A malformed URL prevented a URL request from being initiated.

static var callIsActive: URLError.Code

A connection was attempted while a phone call is active on a network that does not support simultaneous phone and data communication (EDGE or GPRS).

static var cancelled: URLError.Code

An asynchronous load has been canceled.

static var cannotCloseFile: URLError.Code

A download task couldn’t close the downloaded file on disk.

static var cannotConnectToHost: URLError.Code

An attempt to connect to a host failed.

static var cannotCreateFile: URLError.Code

A download task couldn’t create the downloaded file on disk because of an I/O failure.

static var cannotDecodeContentData: URLError.Code

Content data received during a connection request had an unknown content encoding.

static var cannotDecodeRawData: URLError.Code

Content data received during a connection request could not be decoded for a known content encoding.

static var cannotFindHost: URLError.Code

The host name for a URL could not be resolved.

static var cannotLoadFromNetwork: URLError.Code

A request to load an item only from the cache could not be satisfied.

static var cannotMoveFile: URLError.Code

A download task was unable to move a downloaded file on disk.

static var cannotOpenFile: URLError.Code

A download task was unable to open the downloaded file on disk.

static var cannotParseResponse: URLError.Code

A task could not parse a response.

static var cannotRemoveFile: URLError.Code

A download task was unable to remove a downloaded file from disk.

static var cannotWriteToFile: URLError.Code

A download task was unable to write to the downloaded file on disk.

static var clientCertificateRejected: URLError.Code

A server certificate was rejected.

static var clientCertificateRequired: URLError.Code

A client certificate was required to authenticate an SSL connection during a request.

static var dataLengthExceedsMaximum: URLError.Code

The length of the resource data exceeds the maximum allowed.

static var dataNotAllowed: URLError.Code

The cellular network disallowed a connection.

static var dnsLookupFailed: URLError.Code

The host address could not be found via DNS lookup.

static var downloadDecodingFailedMidStream: URLError.Code

A download task failed to decode an encoded file during the download.

static var downloadDecodingFailedToComplete: URLError.Code

A download task failed to decode an encoded file after downloading.

static var fileIsDirectory: URLError.Code

A request for an FTP file resulted in the server responding that the file is not a plain file, but a directory.

static var httpTooManyRedirects: URLError.Code

A redirect loop has been detected or the threshold for number of allowable redirects has been exceeded (currently 16).

static var internationalRoamingOff: URLError.Code

The attempted connection required activating a data context while roaming, but international roaming is disabled.

static var networkConnectionLost: URLError.Code

A client or server connection was severed in the middle of an in-progress load.

static var noPermissionsToReadFile: URLError.Code

A resource couldn’t be read because of insufficient permissions.

static var notConnectedToInternet: URLError.Code

A network resource was requested, but an internet connection has not been established and cannot be established automatically.

static var redirectToNonExistentLocation: URLError.Code

A redirect was specified by way of server response code, but the server did not accompany this code with a redirect URL.

static var requestBodyStreamExhausted: URLError.Code

A body stream is needed but the client did not provide one.

static var resourceUnavailable: URLError.Code

A requested resource couldn’t be retrieved.

static var serverCertificateHasBadDate: URLError.Code

A server certificate had a date which indicates it has expired, or is not yet valid.

static var serverCertificateHasUnknownRoot: URLError.Code

A server certificate was not signed by any root server.

static var serverCertificateNotYetValid: URLError.Code

A server certificate is not yet valid.

static var serverCertificateUntrusted: URLError.Code

A server certificate was signed by a root server that isn’t trusted.

static var secureConnectionFailed: URLError.Code

An attempt to establish a secure connection failed for reasons that can’t be expressed more specifically.

static var timedOut: URLError.Code

An asynchronous operation timed out.

static var unknown: URLError.Code

The URL Loading System encountered an error that it can’t interpret.

static var unsupportedURL: URLError.Code

A properly formed URL couldn’t be handled by the framework.

static var userAuthenticationRequired: URLError.Code

Authentication is required to access a resource.

static var userCancelledAuthentication: URLError.Code

An asynchronous request for authentication has been canceled by the user.

static var zeroByteResource: URLError.Code

A server reported that a URL has a non-zero content length, but terminated the network connection gracefully without sending any data.

Operator Functions

static func != (URLError, URLError) -> Bool

Returns a Boolean value indicating whether two values are not equal.

See Also


URL Loading System Error Info Keys

Recognize these keys from the user info dictionary of error objects produced by URL Loading APIs.