connection(_:didSendBodyData:totalBytesWritten:totalBytesExpectedToWrite:)
Sent as the body (message data) of a request is transmitted (such as in an HTTP POST request).
Declaration
optional func connection(_ connection: NSURLConnection, didSendBodyData bytesWritten: Int, totalBytesWritten: Int, totalBytesExpectedToWrite: Int)Parameters
- connection:
The connection sending the message.
- bytesWritten:
The number of bytes written in the latest write.
- totalBytesWritten:
The total number of bytes written for this connection.
- totalBytesExpectedToWrite:
The number of bytes the connection expects to write.
Discussion
This method provides an estimate of the progress of a URL upload.
The value of totalBytesExpectedToWrite may change during the upload if the request needs to be retransmitted due to a lost connection or an authentication challenge from the server.