iOS: how to perform a HTTP POST request?

Question

I'm approaching iOS development and I'd like to have one of my first applications to perform a HTTP POST request.

As far as I can understand, I should manage the connection which handles the request via a NSURLConnection object, which forces me to have a delegate object, which in turn will handle data events.

Could someone please clarify the task with a practical example?

I should contact an https endpoint sending authentication data (username and password) and getting back a plain text response.

Answer 1

Xcode 8 and Swift 3.0

Using URLSession:

 let url = URL(string:"Download URL")!
 let req = NSMutableURLRequest(url:url)
 let config = URLSessionConfiguration.default
 let session = URLSession(configuration: config, delegate: self, delegateQueue: OperationQueue.main)

 let task : URLSessionDownloadTask = session.downloadTask(with: req as URLRequest)
task.resume()

URLSession Delegate call:

func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {

}


func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, 
didWriteData bytesWritten: Int64, totalBytesWritten writ: Int64, totalBytesExpectedToWrite exp: Int64) {
                   print("downloaded \(100*writ/exp)" as AnyObject)

}

func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL){

}

Using Block GET/POST/PUT/DELETE:

 let request = NSMutableURLRequest(url: URL(string: "Your API URL here" ,param: param))!,
        cachePolicy: .useProtocolCachePolicy,
        timeoutInterval:"Your request timeout time in Seconds")
    request.httpMethod = "GET"
    request.allHTTPHeaderFields = headers as? [String : String] 

    let session = URLSession.shared

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

        if (error != nil) {
         print(error)
         } else {
         print(httpResponse)
         }

        DispatchQueue.main.async {
           //Update your UI here
        }

    }
    dataTask.resume()

Working fine for me.. try it 100% result guarantee