Response Data via URLSessionUploadTask - ios

Question

I am writing simple handler for communication with REST API on server (currently local). Everything goes well so far with downloading and uploading data from/to server.
What I am trying to achieve now is to be able to handle JSON response returned by server after uploading data. This message is something like this:
{"message":"Record successfully added.","recordID":30}
Important is for me the recordID, because I need to assign it to relevant NSManagedObject. I use delegation attitude instead of completionHandler so I would be able to manage progress of the upload. Appropriate delegate class implements these protocols with all methods:
class ConstructoHTTPHelper:NSObject, URLSessionDelegate, URLSessionDataDelegate, URLSessionTaskDelegate, URLSessionDownloadDelegate, URLSessionStreamDelegate { ... }
Here comes the issue because as far as I create upload task with something like this:
let config = URLSessionConfiguration.default
self.session = URLSession(configuration: config, delegate: self, delegateQueue: OperationQueue.main) //URLSession(configuration: config)
var request:URLRequest = URLRequest(url:address)
request.httpMethod = "POST"
let data = // creation of data ...
let fileURL = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false).appendingPathComponent("uploadData")
do {
try data.write(to: fileURL)
} catch {
// handling error
}
self.sessionUploadTask = self.session?.uploadTask(with: request, fromFile: fileURL)
self.sessionUploadTask!.resume()
The delegate func for handling data:
func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {}
returned by server is never called.
What is strange to me is that when I use completion Handler like the one below, It prints the JSON well:
self.sessionUploadTask = self.session?.uploadTask(with: request, from: data, completionHandler: { (data, response, error) in
print(NSString(data: data!, encoding: String.Encoding.utf8.rawValue)!)
})
So it looks to me that uploadTask is limited in this way. Any suggestions?
Thanks

Answer 1

I probably found the answer, just add this to URLSession:dataTask:didReceiveResponse:completionHandler: delegate method.
completionHandler(URLSession.ResponseDisposition.allow)
I found solution in this thread.

Answer 2

try this!, get a NSMutableData as buffer like this globally
fileprivate var buffer:NSMutableData = NSMutableData()
and in your URLSession delegate method add,
func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
if let _ = error {
print(error!.localizedDescription)
}else {
// do your parsing with buffer here.
}
}
func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
buffer.append(data)
}