NSURLConnection Using iOS Swift

Question

I am trying to run this tutorial and connect to the JSON api using Swift and NSURLConnection . I see that it clicks on the URL, but connectionDidFinishLoading does not seem to work.

 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'm just trying to see the returned data. I would like to connect it to the view controller as soon as I am sure that it works. Is there something wrong with this and this is causing the problem?

Answer 1

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, the connection to the URL

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. Download image (file)

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() 

Answer 2

An abridged 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 did not indicate in your question where you have this code,

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

If var is a local variable, then the Remote class will be released immediately after the connect (query: NSString) method completes, but before the data is returned. As you can see from my code, I usually implement reinit (or dealloc so far) to make sure when my instances leave. You must add this to your Remote class to make sure your problem.

Answer 3

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()