Open Radar

 
Summary:

When using code like this to set the HTTP “Accept” header:

        let conf = NSURLSessionConfiguration.defaultSessionConfiguration()
        conf.HTTPAdditionalHeaders = ["Accept": "application/json;odata=verbose"]
        
        let session = NSURLSession(configuration: conf)
        
        let url = NSURL(string: "http://ip.jsontest.com/")!
        
        session.dataTaskWithURL(url).resume()

…and viewing the resulting request in a proxy like Charles Proxy, the “Accept” value no longer gets set in iOS 8.3 for both Simulator and device.  This previously worked fine in iOS 7 and 8.1.3

Headers resulting from above code under iOS 7 & 8.1.3:

	GET / HTTP/1.1
Host	ip.jsontest.com
Accept	application/json;odata=verbose
User-Agent	AcceptHeaderB0rkag3Test/1 CFNetwork/672.1.13 Darwin/14.1.0
Accept-Language	en-us
Accept-Encoding	gzip, deflate
Connection	keep-alive


Headers resulting from above code under iOS 8.3 (both beta 1 & 2):

	GET / HTTP/1.1
Host	ip.jsontest.com
Accept	*/*
User-Agent	AcceptHeaderB0rkag3Test/1 CFNetwork/711.3.12 Darwin/14.1.0
Accept-Language	en-us
Accept-Encoding	gzip, deflate
Connection	keep-alive


Steps to Reproduce:

1. Setup a device to route through a proxy like Charles Proxy, or any other tool that will let you view HTTP headers for requests made
2. Run the attached project
3. Press the “Make Request” button
4. Review HTTP headers
5. Observe the “Accept” header is not set - it remains */*
6. Re-run on iOS 8.1.3 and observe the header is set.

Expected Results:

I would expect setting the “Accept” header to still work as it has done on previous iOS releases.

Actual Results:

“Accept” header not set.

Regression:

Problem NOT present on iOS 7, 8.1.3
Problem IS present on iOS 8.3 beta 1 & 2

Notes:

This has actually broken an app I’m developing for a client, so it’s not a contrived example.