How can I tell when data has been received with NSURLConnection? - php

Question

I'm working on a Swift application that uses a PHP web service to query a database. One issue - I have no idea how to tell when data has been received in the model class, so I can't update the view! How can I tell if the connection has finished, then update said view? For this purpose, I've created a dummy label called text. Thanks for the help in advance, and happy holidays!
User.swift
import Foundation
class User: NSObject {
var firstName: String?
var lastName: String?
var username: String
var password: String
var email: String?
var recievedJSON: NSMutableData = NSMutableData()
var userData: [[String: String]]!
var verified: Bool = false
required init(username: String, password: String) {
self.username = username
self.password = password
}
init(firstName: String, lastName: String, username: String, password: String, email: String) {
self.firstName = firstName
self.lastName = lastName
self.username = username
self.password = password
self.email = email
}
func attemptRegister() {
var variables: [String] = ["firstname=" + self.firstName! + "&"]
variables.append("lastname=" + self.lastName! + "&")
variables.append("username=" + self.username + "&")
variables.append("password=" + self.password + "&")
variables.append("email=" + self.email!)
request("https://codekaufman.com/register.php", variables: variables)
}
func attemptSignIn() {
var variables: [String] = ["username=" + self.username + "&"]
variables.append("password=" + self.password)
request("https://codekaufman.com/login.php", variables: variables)
println("Attempting sign-in...")
}
private func request(urlPath: String, variables: [String]?) {
var url: NSURL = NSURL(string: urlPath)!
var request: NSMutableURLRequest = NSMutableURLRequest(URL: url)
if(variables != nil) {
request.HTTPMethod = "POST"
var bodyData: NSString = ""
for item in variables! {
bodyData = bodyData + NSString(string: item)
}
request.HTTPBody = bodyData.dataUsingEncoding(NSUTF8StringEncoding)
}
var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)!
connection.start()
println("Connection started.")
}
func connection(connection: NSURLConnection!, didReceiveData data: NSData!){
self.recievedJSON.appendData(data)
println("Possible data recieved.")
}
func connectionDidFinishLoading(connection: NSURLConnection!) {
userData = parseJSON(recievedJSON)
if(userData != nil) {
println("Data recieved:")
println(userData[0])
self.firstName = userData[0]["first_name"]
self.lastName = userData[0]["last_name"]
} else {
println("No data recieved.")
}
}
func parseJSON(inputData: NSData) -> [[String: String]]? {
var error: NSError?
var userData: [[String: String]]!
userData = NSJSONSerialization.JSONObjectWithData(inputData, options: NSJSONReadingOptions.MutableContainers, error: &error) as? [[String: String]]
#if DEBUG
if (userData != nil) {
println("NSData had data, printing and returning.")
println(userData)
} else {
println("NSData empty, returning nil.")
}
#endif
return userData
}
}
ViewController.swift
import UIKit
class ViewController: UIViewController {
#IBAction func prepareForUnwind(seque: UIStoryboardSegue) {
}
#IBOutlet weak var username: UITextField!
#IBOutlet weak var password: UITextField!
#IBOutlet weak var text: UILabel!
#IBAction func signin(sender: AnyObject) {
if(username.text == "" || password.text == "") {
var alert = UIAlertController(title: "Error", message: "Invalid Credentials", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Close", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)
} else {
var attempt: User = User(username: username.text, password: password.text)
attempt.attemptSignIn()
}
}
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
Edit: Based on previous comments/answers, I feel I should clarify. Data is being received. But it takes a few seconds, so how can I signify to the view controller that the data has been received, and the process is finished?

Answer 1

You can add a notification in the view controller with:
func addObserverForName(_ name: String?, object obj: AnyObject?, queue queue: NSOperationQueue?, usingBlock block: (NSNotification!) -> Void) -> NSObjectProtocol
Be sure to remove it in deinit:
func removeObserver(_ notificationObserver: AnyObject)
Send the notification from connectionDidFinishLoading using:
func postNotificationName(_ notificationName: String, object notificationSender: AnyObject?, userInfo userInfo: [NSObject : AnyObject]?)