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

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.

Swift 3.0

AsynchonousRequest

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