Saving username information to a server instead of NSDefaults (iOS) - ios

Question

I have a server for storing username and password data in my application. When testing the app I had everything save to the device locally using NSDefaults, but now that the app is close to being fully launched, I am trying to save them to the server instead, as it is safer that way for the user's information.
When I had it save to NSDefaults, it was easy and short work. Now however, I am trying to POST the data to the server and keep getting build errors. What do I need to change for this to work? Am I not fully understanding how POST and GET works? Thanks. Using Swift 2 as of right now, not my choice, I prefer 3, but my boss isn't letting us update it yet.
The current error is coming from the POST USER DATA TO SERVER section, where xcode claims that userNmeTxt cannot be converted into NSData. Thank you in advance.
EDIT: Error is on line 87: "Cannot convert value of type UITextField! to expected argument type NSData!"
import UIKit
class UserNameViewController: AuthorizationViewController {
#IBOutlet weak var userNameTxt: UITextField!
#IBOutlet weak var continueBtn: UIButton!
var userModel: ProfileModel!
//MARK: - SYSTEMS METHODS
override func viewDidLoad() {
super.viewDidLoad()
userNameTxt.delegate = self
userNameTxt.autocapitalizationType = .Sentences
setEnabledButton()
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
self.navigationController?.navigationBarHidden = false
self.navigationItem.leftBarButtonItem = getBackButton()
self.title = ""
}
override func viewWillDisappear(animated: Bool) {
self.navigationController?.navigationBarHidden = true
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
continueBtn.layer.cornerRadius = 10
}
override func popToRoot(sender:UIBarButtonItem){
self.navigationController!.popViewControllerAnimated(true)
}
//MARK: - CHECK FOR AVALABILITY
func setEnabledButton(){
if userNameTxt.text == "" {
continueBtn.backgroundColor = UIColor.lightGrayColor()
} else {
continueBtn.backgroundColor = UIColor(colorLiteralRed: 63.0/255.0, green: 220.0/255.0, blue: 236.0/255.0, alpha: 1.0)
}
continueBtn.userInteractionEnabled = userNameTxt.text != ""
}
//MARK: - POST USER DATA TO SERVER
func postData(url: String, params: Dictionary<String, String>, completionHandler: (data: NSData?, response: NSURLResponse?, error: NSError?) -> ()) {
// Indicate download
UIApplication.sharedApplication().networkActivityIndicatorVisible = true
let url = NSURL(string: "myPlaceholderURLgoesHere")!
// print("URL: \(url)")
let request = NSMutableURLRequest(URL: url)
let session = NSURLSession.sharedSession()
request.HTTPMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
// Verify downloading data is allowed
do {
request.HTTPBody = try NSJSONSerialization.dataWithJSONObject(params, options: [])
} catch let error as NSError {
print("Error in request post: \(error)")
request.HTTPBody = nil
} catch {
print("Catch all error: \(error)")
}
// Post the data
let task = session.dataTaskWithRequest(request) { data, response, error in
completionHandler(data: userNameTxt, response: userModel, error: error)
// Stop download indication
UIApplication.sharedApplication().networkActivityIndicatorVisible = false
// Stop download indication
}
task.resume()
}
//MARK: - SEGUE
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "toPassword"{
let controller = segue.destinationViewController as! PasswordViewController
controller.userModel = userModel
}
}
//MARK: - IB ACTIONS
#IBAction func continuePressed(sender: AnyObject) {
userModel.userNickName = userNameTxt.text!
performSegueWithIdentifier("toPassword", sender: self)
}
}
extension UserNameViewController: UITextFieldDelegate{
func textFieldDidEndEditing(textField: UITextField) {
self.setEnabledButton()
}
}

Answer 1

There are a couple of things you need to change.
userNameTxt is not the username, it's the UITextField containing the username. The text you need is userNameTxt.text?
If the function is expecting Data, you have to convert your text to Data first
let task = session.dataTaskWithRequest(request) { data, response, error in
completionHandler(data: userNameTxt.text?.data(using: .utf8), response: userModel, error: error)

Answer 2

I assume you have to send the data to the server.
If you don't have too you can save the data in keychain access, see: SO: Keychain Access
In order to resolve the error please edit the question with the error message and line of code (if possible).
I would suggest that you use Alamofire for POST/GET (REST). To use Alamofire you need basic knowledge of Cocoapods. It's better in the long term.
NOTE: There can be two possible error outcomes when you make the request.
1) Incorrect data format or bug from your side
2) Server error due backend bug from server side.
The data can be sent from your device with POST where the data is in the BODY or HEADER of the request. Usually it is in the body (parameters in the alamofire methods).
Here is an example:
import Alamofire
...
// MARK:- Login Feature - Universal Met for login
internal static func loginWith(serverUrl: String, parameters: [String: AnyObject]?, headers: [String: String]?, notificationName: String, serviceType: LoginService)
{
Alamofire.request(.POST, serverUrl, parameters: parameters, headers: headers).responseJSON
{ (response) in
print("\n Login feature - \n")
print(" Login url - \(serverUrl)\n")
print(" Login parameters - \(parameters)\n")
print(" Login notificationName - \(notificationName)\n")
print(" Login response - \(response)\n")
EXCDataParserH.parseResponseFrom(ServiceType.Login(type: serviceType),
operation: nil,
data: response.data,
notification: notificationName)
}
}

Answer 3

Instead of writing the whole thing every time you make a server request, try to do as follows:
import Foundation
import SystemConfiguration
class HTTPHelper{
class func httpPostDataDic(postURL:NSURL,postString:NSString,completionHandler:#escaping (NSDictionary?, NSError?) -> Void ) -> URLSessionTask{
var responseResultData: NSDictionary = NSDictionary()
let request = NSMutableURLRequest(url:postURL as URL);
request.httpMethod = "POST";// Compose a query string
request.httpBody = postString.data(using: String.Encoding.utf8.rawValue);
print(request)
let task = URLSession.shared.dataTask(with: request as URLRequest) {
data, response, error in
if error != nil
{
print("error=\(error)")
completionHandler(nil, error as NSError?)
return
}
let responseString = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)
if let responseString = responseString {
print("responseString = \(responseString)")
}
do {
let myJSON = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
responseResultData=myJSON!
completionHandler(responseResultData, nil)
} catch {
print(error)
}
}
task.resume()
return task
}
}
Now whenever you need to make a server POST request,in your ViewController class, do as follows:
//Requesting server
func requestServer() -> Void{
let postvariable = "Value"
let url = URL(string: "your url")!
let postString = "postkey=\(postvariable)"
HTTPHelper.httpPostDataDic(postURL: url as NSURL, postString: postString) {
(responseResult, error) -> Void in
DispatchQueue.main.async {
if error != nil{
print(error ?? "unknown")
}
else{
print(responseResult ?? "unknown result")
//Parse your response
self.parseResult(result: responseResult!);
}
}
}
}
May I ask you one thing that I didn't understand in your question.
How exactly would you save the login credentials in a server? I mean, if you save the login credentials in the server, how would you authenticate user access to these saved credentials?