[Answer]-Server receives no data from NSURLSessionUploadTask

From the docs for -[NSURLSession uploadTaskWithStreamedRequest:] (looks like that is what you are using):

… The body stream and body data in this request object
are ignored, and NSURLSession calls its delegate’s
URLSession:task:needNewBodyStream: method to provide the body data.

Have you implemented that delegate method?

https://developer.apple.com/library/ios/documentation/Foundation/Reference/NSURLSession_class/Introduction/Introduction.html#//apple_ref/doc/uid/TP40013435-CH1-SW28