Tells the delegate that the data task received the initial reply (headers) from the server.
SDKs
- iOS 7.0+
- macOS 10.9+
- tvOS 9.0+
- watchOS 2.0+
Framework
- Foundation
Declaration
optional func urlSession(_ session: URLSession, dataTask: URLSessionParameters
sessionThe session containing the data task that received an initial reply.
dataTaskThe data task that received an initial reply.
responseA URL response object populated with headers.
completionHandlerA completion handler that your code calls to continue the transfer, passing a constant to indicate whether the transfer should continue as a data task or should become a download task.
If you pass
URLSession, the task continues normally..Response Disposition .allow If you pass
URLSession, the task is canceled..Response Disposition .cancel If you pass
URLSessionas the disposition, your delegate’s.Response Disposition .become Download urlmethod is called to provide you with the new download task that supersedes the current task.Session(_: data Task: did Become:)
Discussion
This method is optional unless you need to support the (relatively obscure) multipart/x-mixed-replace content type. With that content type, the server sends a series of parts, each of which is intended to replace the previous part. The session calls this method at the beginning of each part, and you should then display, discard, or otherwise process the previous part, as appropriate.
If you do not provide this delegate method, the session always allows the task to continue.