Nsdata Contentsofurl Constructor Returns Nil

NSData(contentsOfURL: url) always returning nil

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SWIFT: NSData contentsOfUrl returns nil from valid URL

In my specific case, it was the actual data in the URL that was missing... So that is why it returned nil.

Thanks guys for trying to help :)

Upgraded to Xcode 6.1.1, now NSData(contentsOfURL:) always returns nil

Rebooting the Mac fixed it. I hadn't rebootedsince updating to Xcode 6.1.1.

Swift - NSURL error

The NSURL constructor you're calling has got this signature:

convenience init?(string URLString: String)

? means that the constructor may not return a value, hence it is considered as an optional.

Same goes for the NSData constructor:

init?(contentsOfURL url: NSURL)

A quick fix is:

let myProfilePictureURL = NSURL(string: "http://graph.facebook.com/bobdylan/picture")
let imageData = NSData(contentsOfURL: myProfilePictureURL!)
self.myImage.image = UIImage(data: imageData!)

The best solution is to check (unwrap) those optionals, even if you're sure that they contain a value!

You can find more infos on optionals here: link to official Apple documentation.

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Your problem is that one (or more) of your optionals is nil when you try to access it. Its important to understand optionals if you are doing swift development, I'd recommend going through the documentation.

let dataURL: NSData = NSData(contentsOfURL: NSURL(string: strURL)!)!
let strResult: String = String(data: dataURL, encoding: NSUTF8StringEncoding)!

In the code above, when you use ! you are telling swift that you are 100% sure that optional contains a value. There might be an issue in either your construction of a url NSURL(strUrl)! or when calling the NSData(...) constructor and unwrapping its result with !.

Try something like this:

if let url = NSURL(string: strURL) {
   if let data = NSData(contentsOfURL: url) {
       var strResult = String(data: data, encoding: NSUTF8StringEncoding)
       print(strResult ?? "Something Went Wrong")
   }
   else { // get rid of this else when you find your issue
       print("Could not instantiate an NSData object out of that url")
   }
}
else {  // get rid of this else when you find your issue
   print("Your URL is nil!, check the strUrl")
}

Here, we first unwrap the NSURL as NSURL(string) constructor returns an optional (the string you pass might be an invalid URL). We then unwrap the NSData object and then coalesce the strResult when printing it (as its also an optional).

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