NSURLConnection Using iOS Swift

Question

I am trying to follow this tutorial and connect to a JSON api using Swift and NSURLConnection. I can see that it is hitting the url but the connectionDidFinishLoading does not seem to fire.

import UIKit

class Remote: NSObject {

    var host = "http://localhost:3000"
    var query = String()
    var data: NSMutableData = NSMutableData()

    func connect(query:NSString) {
        self.query = query
        var url = self.document()
        var conn = NSURLConnection(request: url, delegate: self, startImmediately: true)
    }

    func endpoint() -> NSURL {
        var query = self.host + self.query
        return NSURL(string: query)
    }

    func document() -> NSURLRequest {
        return NSURLRequest( URL: self.endpoint() )
    }

    func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {
        // Recieved a new request, clear out the data object
        self.data = NSMutableData()
    }

    func connection(connection: NSURLConnection!, didReceiveData conData: NSData!) {
        // Append the recieved chunk of data to our data object
        self.data.appendData(conData)
    }

    func connectionDidFinishLoading(connection: NSURLConnection!) {
        // Request complete, self.data should now hold the resulting info
        // Convert the retrieved data in to an object through JSON deserialization
        var err: NSError
        var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(self.data, options:    NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary

        println(jsonResult.count)
    }


}


// Excecute the code

var remote = Remote()
remote.connect("/apis")

At this point I am just trying to see the data that is returned. I would like to hook it into a view controller once I am sure this is working. Is there something wrong with doing it this way and that is causing an issue?

It's the playground that's the issue, not your code. possible duplicate of [How do I run Asynchronous callbacks in Playground](http://stackoverflow.com/questions/24058336/how-do-i-run-asynchronous-callbacks-in-playground) — Chuck, Jun 12 '14 at 13:29

PREMKUMAR · Answer 1 · 2017-01-02T09:38:21.770

Check Below Codes :

1. SynchronousRequest

Swift 1.2

    let urlPath: String = "YOUR_URL_HERE"
    var url: NSURL = NSURL(string: urlPath)!
    var request1: NSURLRequest = NSURLRequest(URL: url)
    var response: AutoreleasingUnsafeMutablePointer<NSURLResponse?>=nil
    var dataVal: NSData =  NSURLConnection.sendSynchronousRequest(request1, returningResponse: response, error:nil)!
    var err: NSError
    println(response)
    var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataVal, options: NSJSONReadingOptions.MutableContainers, error: &err) as? NSDictionary
    println("Synchronous\(jsonResult)")

Swift 2.0 +

let urlPath: String = "YOUR_URL_HERE"
    let url: NSURL = NSURL(string: urlPath)!
    let request1: NSURLRequest = NSURLRequest(URL: url)
    let response: AutoreleasingUnsafeMutablePointer<NSURLResponse?>=nil


    do{

        let dataVal = try NSURLConnection.sendSynchronousRequest(request1, returningResponse: response)

            print(response)
            do {
                if let jsonResult = try NSJSONSerialization.JSONObjectWithData(dataVal, options: []) as? NSDictionary {
                    print("Synchronous\(jsonResult)")
                }
            } catch let error as NSError {
                print(error.localizedDescription)
            }



    }catch let error as NSError
    {
         print(error.localizedDescription)
    }

2. AsynchonousRequest

Swift 1.2

let urlPath: String = "YOUR_URL_HERE"
    var url: NSURL = NSURL(string: urlPath)!
    var request1: NSURLRequest = NSURLRequest(URL: url)
    let queue:NSOperationQueue = NSOperationQueue()
    NSURLConnection.sendAsynchronousRequest(request1, queue: queue, completionHandler:{ (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void in
        var err: NSError
        var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
        println("Asynchronous\(jsonResult)")
       })

Swift 2.0 +

let urlPath: String = "YOUR_URL_HERE"
    let url: NSURL = NSURL(string: urlPath)!
    let request1: NSURLRequest = NSURLRequest(URL: url)
    let queue:NSOperationQueue = NSOperationQueue()

    NSURLConnection.sendAsynchronousRequest(request1, queue: queue, completionHandler:{ (response: NSURLResponse?, data: NSData?, error: NSError?) -> Void in

        do {
            if let jsonResult = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? NSDictionary {
                print("ASynchronous\(jsonResult)")
            }
        } catch let error as NSError {
            print(error.localizedDescription)
        }


    })

3. As usual URL connection

Swift 1.2

    var dataVal = NSMutableData()
    let urlPath: String = "YOUR URL HERE"
    var url: NSURL = NSURL(string: urlPath)!
    var request: NSURLRequest = NSURLRequest(URL: url)
    var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: true)!
    connection.start()

Then

 func connection(connection: NSURLConnection!, didReceiveData data: NSData!){
    self.dataVal?.appendData(data)
}


func connectionDidFinishLoading(connection: NSURLConnection!)
{
    var error: NSErrorPointer=nil

    var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataVal!, options: NSJSONReadingOptions.MutableContainers, error: error) as NSDictionary

    println(jsonResult)



}

Swift 2.0 +

   var dataVal = NSMutableData()
    let urlPath: String = "YOUR URL HERE"
    var url: NSURL = NSURL(string: urlPath)!
    var request: NSURLRequest = NSURLRequest(URL: url)
    var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: true)!
    connection.start()

Then

func connection(connection: NSURLConnection!, didReceiveData data: NSData!){
    dataVal.appendData(data)
}


func connectionDidFinishLoading(connection: NSURLConnection!)
{

    do {
        if let jsonResult = try NSJSONSerialization.JSONObjectWithData(dataVal, options: []) as? NSDictionary {
            print(jsonResult)
        }
    } catch let error as NSError {
        print(error.localizedDescription)
    }

}

4. Asynchronous POST Request

Swift 1.2

    let urlPath: String = "YOUR URL HERE"
    var url: NSURL = NSURL(string: urlPath)!
    var request1: NSMutableURLRequest = NSMutableURLRequest(URL: url)

    request1.HTTPMethod = "POST"
     var stringPost="deviceToken=123456" // Key and Value

    let data = stringPost.dataUsingEncoding(NSUTF8StringEncoding)

    request1.timeoutInterval = 60
    request1.HTTPBody=data
    request1.HTTPShouldHandleCookies=false

    let queue:NSOperationQueue = NSOperationQueue()

     NSURLConnection.sendAsynchronousRequest(request1, queue: queue, completionHandler:{ (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void in


        var err: NSError

        var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
        println("AsSynchronous\(jsonResult)")


        })

Swift 2.0 +

let urlPath: String = "YOUR URL HERE"
    let url: NSURL = NSURL(string: urlPath)!
    let request1: NSMutableURLRequest = NSMutableURLRequest(URL: url)

    request1.HTTPMethod = "POST"
    let stringPost="deviceToken=123456" // Key and Value

    let data = stringPost.dataUsingEncoding(NSUTF8StringEncoding)

    request1.timeoutInterval = 60
    request1.HTTPBody=data
    request1.HTTPShouldHandleCookies=false

    let queue:NSOperationQueue = NSOperationQueue()

    NSURLConnection.sendAsynchronousRequest(request1, queue: queue, completionHandler:{ (response: NSURLResponse?, data: NSData?, error: NSError?) -> Void in

        do {
            if let jsonResult = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? NSDictionary {
                print("ASynchronous\(jsonResult)")
            }
        } catch let error as NSError {
            print(error.localizedDescription)
        }


    })

5. Asynchronous GET Request

Swift 1.2

    let urlPath: String = "YOUR URL HERE"
    var url: NSURL = NSURL(string: urlPath)!
    var request1: NSMutableURLRequest = NSMutableURLRequest(URL: url)

    request1.HTTPMethod = "GET"
    request1.timeoutInterval = 60
    let queue:NSOperationQueue = NSOperationQueue()

     NSURLConnection.sendAsynchronousRequest(request1, queue: queue, completionHandler:{ (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void in


        var err: NSError

        var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
        println("AsSynchronous\(jsonResult)")


        })

Swift 2.0 +

let urlPath: String = "YOUR URL HERE"
    let url: NSURL = NSURL(string: urlPath)!
    let request1: NSMutableURLRequest = NSMutableURLRequest(URL: url)

    request1.HTTPMethod = "GET"
    let queue:NSOperationQueue = NSOperationQueue()

    NSURLConnection.sendAsynchronousRequest(request1, queue: queue, completionHandler:{ (response: NSURLResponse?, data: NSData?, error: NSError?) -> Void in

        do {
            if let jsonResult = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? NSDictionary {
                print("ASynchronous\(jsonResult)")
            }
        } catch let error as NSError {
            print(error.localizedDescription)
        }


    })

6. Image(File) Upload

Swift 2.0 +

  let mainURL = "YOUR_URL_HERE"

    let url = NSURL(string: mainURL)
    let request = NSMutableURLRequest(URL: url!)
    let boundary = "78876565564454554547676"
    request.addValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")


    request.HTTPMethod = "POST" // POST OR PUT What you want
    let session = NSURLSession(configuration:NSURLSessionConfiguration.defaultSessionConfiguration(), delegate: nil, delegateQueue: nil)

    let imageData = UIImageJPEGRepresentation(UIImage(named: "Test.jpeg")!, 1)





    var body = NSMutableData()

    body.appendData("--\(boundary)\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)

    // Append your parameters

    body.appendData("Content-Disposition: form-data; name=\"name\"\r\n\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
    body.appendData("PREMKUMAR\r\n".dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)!)
    body.appendData("--\(boundary)\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)

    body.appendData("Content-Disposition: form-data; name=\"description\"\r\n\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
    body.appendData("IOS_DEVELOPER\r\n".dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)!)
    body.appendData("--\(boundary)\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)


    // Append your Image/File Data

    var imageNameval = "HELLO.jpg"

    body.appendData("--\(boundary)\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
    body.appendData("Content-Disposition: form-data; name=\"profile_photo\"; filename=\"\(imageNameval)\"\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
    body.appendData("Content-Type: image/jpeg\r\n\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
    body.appendData(imageData!)
    body.appendData("\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)

    body.appendData("--\(boundary)--\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)

    request.HTTPBody = body




    let dataTask = session.dataTaskWithRequest(request) { (data, response, error) -> Void in

        if error != nil {

            //handle error


        }
        else {




            let outputString : NSString = NSString(data:data!, encoding:NSUTF8StringEncoding)!
            print("Response:\(outputString)")


        }
    }
    dataTask.resume()

7. GET,POST,Etc Swift 3.0 +

let request = NSMutableURLRequest(url: URL(string: "YOUR_URL_HERE" ,param: param))!,
    cachePolicy: .useProtocolCachePolicy,
    timeoutInterval:60)
request.httpMethod = "POST" // POST ,GET, PUT What you want 

let session = URLSession.shared



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

do {
            if let jsonResult = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? NSDictionary {
                print("ASynchronous\(jsonResult)")
            }
        } catch let error as NSError {
            print(error.localizedDescription)
        }

    }
    dataTask.resume()

I don't know man. I pasted the AsyncsynchonousRequest directly into a playground file and I get nothing: [screenshot](https://www.dropbox.com/s/ckrwhsul436x4ou/Screenshot%202014-06-12%2000.48.15.png). The examples you have posted are exactly what I have been pouring over for the last three hours. I'm just not sure what I'm missing. — Ross Nelson, Jun 12 '14 at 04:49
Do these requests work with the `AFP` and `SMB` protocols as well? — Matt, Aug 11 '14 at 19:08
Replace AutoreleasingUnsafePointer with AutoreleasingUnsafeMutablePointer — Mr. Flibble, Oct 22 '14 at 13:23
the 1st one in xcode6.1 will block and get, "fatal error: unexpectedly found nil while unwrapping an Optional value" for any website — tong, Nov 11 '14 at 14:29
In xcode 6.1 you need to place a bang like this: var url: NSURL = NSURL(string: urlPath)! — Pellet, Nov 17 '14 at 11:11
@PREMKUMAR for synchronous and asynchronous you are not passed and used the error and err variable. — karthikPrabhu Alagu, Mar 24 '15 at 17:13
In the first code snippet, where was `var err: NSError` used? On the side note, this is a great answer but I think it would be better if the snippets are more readable. — ton, Apr 24 '15 at 17:34
The code for the AsynchonousRequest throws error: "AnyObject? is not convertable to NSDictionary" — TestinginProd, Apr 27 '15 at 19:37
In 2. AsynchonousRequest, how do I save the response to a string? — Josh, May 08 '15 at 13:15
sendAsynchronousRequest was depreciated in iOS 9, user URLSession.dataTask instead — Sumit, Dec 02 '16 at 05:38

score 3 · Answer 2 · answered Jun 12 '14 at 05:45

An abbreviated version of your code worked for me,

class Remote: NSObject {

    var data = NSMutableData()

    func connect(query:NSString) {
        var url =  NSURL.URLWithString("http://www.google.com")
        var request = NSURLRequest(URL: url)
        var conn = NSURLConnection(request: request, delegate: self, startImmediately: true)
    }


     func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {
        println("didReceiveResponse")
    }

    func connection(connection: NSURLConnection!, didReceiveData conData: NSData!) {
        self.data.appendData(conData)
    }

    func connectionDidFinishLoading(connection: NSURLConnection!) {
        println(self.data)
    }


    deinit {
        println("deiniting")
    }
}

This is the code I used in the calling class,

class ViewController: UIViewController {

    var remote = Remote()


    @IBAction func downloadTest(sender : UIButton) {
        remote.connect("/apis")
    }

}

You didn't specify in your question where you had this code,

var remote = Remote()
remote.connect("/apis")

If var is a local variable, then the Remote class will be deallocated right after the connect(query:NSString) method finishes, but before the data returns. As you can see by my code, I usually implement reinit (or dealloc up to now) just to make sure when my instances go away. You should add that to your Remote class to see if that's your problem.

Another important point: class should be derived from NSObject! — Tejasvi Hegde, Jul 13 '14 at 08:24

kiewic · Answer 3 · 2016-12-05T15:45:20.240

1

Swift 3.0

AsynchonousRequest

let urlString = "http://heyhttp.org/me.json"
var request = URLRequest(url: URL(string: urlString)!)
let session = URLSession.shared

session.dataTask(with: request) {data, response, error in
  if error != nil {
    print(error!.localizedDescription)
    return
  }

  do {
    let jsonResult: NSDictionary? = try JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.mutableContainers) as? NSDictionary
    print("Synchronous\(jsonResult)")
  } catch {
    print(error.localizedDescription)
  }
}.resume()

edited Dec 05 '16 at 15:45

answered Dec 05 '16 at 07:56

kiewic

15,852
13
78
101

Both methods are deprecated meanwhile. It's not recommended to use them anymore. – vadian Dec 05 '16 at 08:02
Good point. Thank you for letting me know, I have replaced `sendSynchronousRequest(_:returning:)` and `sendAsynchronousRequest(_:queue:completionHandler:)` with `dataTask(with:completionHandler:)`. – kiewic Dec 05 '16 at 15:47

NSURLConnection Using iOS Swift

3 Answers3

Swift 3.0

AsynchonousRequest

Linked