NSURLSession dataTaskWithRequest Swift

Question

I have the following code:

var resultData:NSData?

task = session!.dataTaskWithRequest(request) { (data: NSData!, response: NSURLResponse!, error: NSError!) in

    if ((error) != nil) {
        println("Error")
        return
    }
    resultData = data
}

task!.resume()

However, after execution the resultData is nil. How can I get the data that's been returned by the request?

Its an Async function so you have to handle the result data inside the function. follow the code below — dhanasekar, May 03 '17 at 13:25

score 2 · Accepted Answer · answered May 03 '17 at 13:39

Check if your data is nil and then you can use it

Here is a Swift 3 example:

let url = NSURL(string: "https://itunes.apple.com/search?term=jack+johnson&limit=2")!
let request = NSMutableURLRequest(url: url as URL)
let session = URLSession.shared

let task = session.dataTask(with: request as URLRequest) { data, response, error in
    if error != nil {
        print("error: \(error!.localizedDescription): \(String(describing: error))")
    }
    else if data != nil {
        if let str = NSString(data: data!, encoding: String.Encoding.utf8.rawValue) {
            print("Received data:\n\(str)")
        }
        else {
            print("unable to convert data to text")
        }
    }

}
task.resume()

dhanasekar · Answer 2 · 2017-05-03T13:22:03.373

the dataTask will execute the function is an async, if you want to use the result data it has to be used inside the data task function. now the print statement will print the response. If you use resultData outside the dataTask func it will return nil

var resultData:NSData?

let dataTask = session.dataTask(with: request as URLRequest) {
            (data, response, error) in

            guard let data = data, error == nil else { return }

            if error != nil {
                error
}
resultData = data
print(NSString(data: data, encoding: String.Encoding.utf8.rawValue)!)
}dataTask.resume()

NSURLSession dataTaskWithRequest Swift

2 Answers2