Swift JSON Parse execution on viewLoad - ios

Question

Im currently struggling with a small issue on my viewController. I have stored user information to hold the users logged in status, anyways when the user opens the app they are shown a "Profile" page. Im trying to (in this example return the email) return values related to that user as the app is opened but dont know how one would execute the code on the controller itself, my JSON is posted below and returns the correct needed information. However my Label will still not get the value of the users Email stored when they open the app. Label stays blank!
let myUrl = NSURL(string: "http://www.mywebsite.co.za/php/scripts/getuserEmail.php");
let request = NSMutableURLRequest(URL:myUrl!);
request.HTTPMethod = "POST";
let postString = "user_id=\(userId)";
request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding);
let task = NSURLSession.sharedSession().dataTaskWithRequest(request)
{
data, response, error in
println(" response = \(response)")
let responseString = NSString(data: data, encoding: NSUTF8StringEncoding)
println("response data = \(responseString)")
var err: NSError?
var json = NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers, error: &err) as? NSDictionary
if let parseJSON = json
{
var userEmail = parseJSON["userEmail"] as? String
self.usersEmail.text = userEmail
}
}
Would basically like the code to execute and update my label as that view opens, as the user has the ability to change the email from another viewController already so the email should update accordingly. Any other information will gladly be provided.
Added: println to console will not execute past the assigning of the myUrl variable. The reply below will still not work however this is my full code on viewWillAppear:
override func viewWillAppear(animated: Bool) {
super.viewDidAppear(animated)
let userFirstName = NSUserDefaults.standardUserDefaults().stringForKey("userFirstName")
let userLastName = NSUserDefaults.standardUserDefaults().stringForKey("userLastName")
var userFullName = userFirstName!
userFullNameLabel.text = userFullName
let userId:String? = NSUserDefaults.standardUserDefaults().stringForKey("userId")
let imageUrl = NSURL(string:"http://www.mywebsite.co.za/profile-pictures/\(userId!)/user-profile.jpg")
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) {
let imageData = NSData(contentsOfURL: imageUrl!)
if(imageData != nil )
{
dispatch_async(dispatch_get_main_queue(),{
self.profilePictureImageVIew.image = UIImage(data: imageData!)
self.profilePictureImageVIew.backgroundColor = UIColor.clearColor()
})
}
}
// Send HTTP POST
let myUrl = NSURL(string: "http://www.mywebsite.co.za/php/scripts/getuserEmail.php");
let request = NSMutableURLRequest(URL:myUrl!);
request.HTTPMethod = "POST";
let postString = "user_id=\(userId)";
request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding);
let task = NSURLSession.sharedSession().dataTaskWithRequest(request)
{
data, response, error in
// You can print out response object
println("******* response = \(response)")
// Print out reponse body
let responseString = NSString(data: data, encoding: NSUTF8StringEncoding)
println("****** response data = \(responseString)")
var err: NSError?
var json = NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers, error: &err) as? NSDictionary
if let parseJSON = json
{
var userEmail = parseJSON["userEmail"] as? String
self.usersEmail.text = userEmail
}
}
}

Answer 1

If I understand correctly, you're saying the page appears and your call to the web has not finished and assigned to the self.usersEmail.text yet. What I did in my project was dispatch the commands in a block like yours asynchronously on the main queue. Try doing this inside your if statement:
dispatch_async(dispatch_get_main_queue()) {
var userEmail = parseJSON["userEmail"] as? String
self.usersEmail.text = userEmail
}
Hopefully this helps. It may be improper, but hopefully somebody can let me know if it is. It works for me so far.
You also need to resume the task after its block:
let myUrl = NSURL(string: "http://www.mywebsite.co.za/php/scripts/getuserEmail.php");
let request = NSMutableURLRequest(URL:myUrl!);
request.HTTPMethod = "POST";
let postString = "user_id=\(userId)";
request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding);
let task = NSURLSession.sharedSession().dataTaskWithRequest(request)
{
data, response, error in
// You can print out response object
println("******* response = \(response)")
// Print out reponse body
let responseString = NSString(data: data, encoding: NSUTF8StringEncoding)
println("****** response data = \(responseString)")
var err: NSError?
var json = NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers, error: &err) as? NSDictionary
if let parseJSON = json
{
var userEmail = parseJSON["userEmail"] as? String
self.usersEmail.text = userEmail
}
}
task.resume()

Answer 2

Thank you grdavis, marked as answer, I had however needed to change a few things to get the result I wanted and I just wanted to post the updated answer.
Moved to viewdidLoad and not viewWillAppear
When monitoring console the userID was not alone when being sent over the URL thus adding a '!' to the string fixed this too before sending the url
The resume worked
Below is my updated code, thank you again. Label updates like desired:
// Send HTTP POST
let userId:String? = NSUserDefaults.standardUserDefaults().stringForKey("userId")
let myUrl = NSURL(string: "http://www.mywebsite.co.za/php/scripts/getuserEmail.php");
let request = NSMutableURLRequest(URL:myUrl!);
request.HTTPMethod = "POST";
let postString = "user_id=\(userId!)";
request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding);
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)){
let task = NSURLSession.sharedSession().dataTaskWithRequest(request)
{
data, response, error in
// You can print out response object
println("******* response = \(response)")
// Print out reponse body
let responseString = NSString(data: data, encoding: NSUTF8StringEncoding)
println("****** response data = \(responseString)")
var err: NSError?
var json = NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers, error: &err) as? NSDictionary
if let parseJSON = json
{
var userEmail = parseJSON["userEmail"] as? String
println("******* userEmail = \(userEmail)")
self.usersEmail.text = userEmail
}
}
task.resume()
}