iOS Swift 3 POST issue - ios

Question

I had some code that I used a while back that worked perfectly. I now wish to use it in my new project which is swift 3 and although I have fixed most errors I still have two left as follows:
The following line of code: var _: NSData? = NSURLConnection.sendSynchronousRequest(request as URLRequest, returning:&response) as NSData produces the following error: Call can throw, but it is not marked with 'try' and the error is not handled
The following line of code: NSLog("Response code: %ld", res?.statusCode ?? <#default value#>); Produces the following error: Editor placeholder in source file.
Any help is appreciated.
Below is the full code which may help solve the issue:
func webViewDidFinishLoad(_ webView: UIWebView) {
UIApplication.shared.isNetworkActivityIndicatorVisible = false
let post:NSString = "userid=349&devicetoken=walan"
NSLog("PostData: %#",post);
let url:NSURL = NSURL(string: "https://str8red.com/updateAPN")!
let postData:NSData = post.data(using: String.Encoding.ascii.rawValue)! as NSData
let postLength:NSString = String( postData.length ) as NSString
let request:NSMutableURLRequest = NSMutableURLRequest(url: url as URL)
request.httpMethod = "POST"
request.httpBody = postData as Data
request.setValue(postLength as String, forHTTPHeaderField: "Content-Length")
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
request.setValue("application/json", forHTTPHeaderField: "Accept")
var _: NSError?
var response: URLResponse?
var _: NSData? = NSURLConnection.sendSynchronousRequest(request as URLRequest, returning:&response) as NSData
let res = response as! HTTPURLResponse!;
NSLog("Response code: %ld", res?.statusCode ?? <#default value#>);
}

Answer 1

You could add try keyword and surround the statement with do {} catch {} as follows:
do {
try NSURLConnection.sendSynchronousRequest(request as URLRequest, returning:&response) as NSData
} catch {
print(error)
}
You will still have a warning about the function has been deprecated since iOS 9.
I will see try to see how the whole function could be re-write in iOS 10, Swift 3.1 syntax, but there's a danger that it might break and will look very different from the rest of your legacy code. Stay tuned, I will update this answer again.
As for the 'placeholder error' you could put some value like '500' for example to default to 'Internal server error'
NSLog("Response code: %ld", res?.statusCode ?? 500);
Update: Here is the function updated to Swift 3, iOS 10.
I only update based on the original intent of the function. Just syntax / API update, no removal / adding any functionality.
func webViewDidFinishLoad(_ webView: UIWebView) {
UIApplication.shared.isNetworkActivityIndicatorVisible = false
let post:String = "userid=349&devicetoken=walan"
NSLog("PostData: %#",post);
let url:URL = URL(string: "https://str8red.com/updateAPN")!
let postData:Data = post.data(using: String.Encoding(rawValue: String.Encoding.ascii.rawValue))!
let postLength: String = String( postData.count )
var request:URLRequest = URLRequest(url: url as URL)
request.httpMethod = "POST"
request.httpBody = postData as Data
request.setValue(postLength, forHTTPHeaderField: "Content-Length")
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
request.setValue("application/json", forHTTPHeaderField: "Accept")
var _: NSError?
var response: URLResponse?
URLSession.shared.dataTask(with: request) { (data, res, error) in
guard error == nil else {
print(error!)
return
}
response = res
}
let res = response as! HTTPURLResponse!;
NSLog("Response code: %ld", res?.statusCode ?? 500);
}