There is a file (CSV) that I want to download. It is behind a login screen on a website. I wanted to show a
Right now, WKWebView instances will ignore any of the default networking storages (NSURLCache, NSHTTPCookieStorage, NSCredentialStorage) and also the standard networking classes you can use to customize the network requests (NSURLProtocol, etc.).
So the cookies of the WKWebView instance are not stored in the standard Cookie storage of your App, and so NSURLSession/NSURLConnection which only uses the standard Cookie storage has no access to the cookies of WKWebView (and exactly this is probably the problem you have: the „login status“ is most likely stored in a cookie, but NSURLSession/NSURLConnection won’t see the cookie).
The same is the case for the cache, for the credentials etc. WKWebView has its own private storages and therefore does not play well with the standard Cocoa networking classes.
You also can’t customize the requests (add your own custom HTTP headers, modify existing headers, etc), use your own custom URL schemes etc, because also NSURLProtocol is not supported by WKWebView.
So right now WKWebView is pretty useless for many Apps, because it does not participate with the standard networking APIs of Cocoa.
I still hope that Apple will change this until iOS 8 gets released, because otherwise WKWebView will be useless for many Apps, and we are probably stick with UIWebView a little bit longer.
So send bug reports to Apple, so Apple gets to know that these issues are serious and needs to be fixed.