Swift communicating with multiple webservices - swift

Question

I currently need to use a web service to do some tasks which are, logging in and receiving a list of information.
After logging in successfully the web service will return 'response' information : {"LoginID":"1","Password":"","Role":"pol","LoginType":"Indevidual","UserID":"6110895204062016","UserRoleID":"20202020202020","RoleID":"999674512042008","PartyId":"1063081525122008","PartyFunctionId":"123123","BranchCode":"10","RoleCode":"123123","Status":{"isError":false,"ErCode":null,"Error":null}}
which is needed to be sent to another web service to get a list of information.
Currently using the login button to call the webserivce to be able to login.
How do I call another webservice using the information from the first webservice?
Code for a better idea:
#IBAction func GetPolicyListButton(_ sender: Any) {
//I will need the information from the second web service to display after clicking this button.. how?
}
#IBAction func LoginButton(_ sender: Any) {
let postString = "cpr=\(usernameField.text!)&password=\(passwordField.text!)"
let url = URL(string:"http://login")!
let postData:Data = postString.data(using: String.Encoding.utf8, allowLossyConversion: false)!
let postLength:String = String(postData.count) as String
var request:URLRequest = URLRequest(url: url)
request.httpMethod = "POST"
request.httpBody = postData
request.setValue(postLength as String, forHTTPHeaderField: "Content-Length")
request.setValue("application/json", forHTTPHeaderField: "Accept")
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else {
print("error=\(error)")
return
}
let httpStatus = response as? HTTPURLResponse
print("statusCode should be 200, but is \(httpStatus!.statusCode)")
print("response = \(response!)")
print(postString)
let responseString = String(data: data, encoding: .utf8)
print("responseString = \(responseString!)")
let start = responseString!.index(responseString!.startIndex, offsetBy: 75)
let end = responseString!.index(responseString!.endIndex, offsetBy: -9)
let range = start..<end
let jsonStr = responseString!.substring(with: range)
print(jsonStr)
let data1 = jsonStr.data(using: .utf8)!
_ = try? JSONSerialization.jsonObject(with: data1) as? [String: Any]
let persondata = try? JSONSerialization.jsonObject(with: data, options: .allowFragments)
let personInfodata = persondata as? [String : Any]
_ = personInfodata?[""] as? [String : Any]
if (responseString?.contains("1001"))!{
DispatchQueue.main.async {
print("incorrect - try again")
let alert = UIAlertController(title: "Try Again", message: "Username or Password Incorrect", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
}
else{
DispatchQueue.main.async {
print("correct good")
let storyboard = UIStoryboard(name: "Maintest", bundle: nil)
let controller = storyboard.instantiateViewController(withIdentifier: "correctone")
self.present(controller, animated: true, completion: nil)
}
}
}
task.resume()
}

Answer 1

You are experiencing the complexity of not working in MVC. While writing an application if you do not properly use MVC the complexity and unnecessary duplication of code can get out of hand and you lose oversight.
A style for example to use is, is to create a LoginModel and a ItemsModel for lack of a better name. Both will be making web requests so be sure to create a class that handles a generic web request or implement a framework like Alamofire (which has some great examples for authentication and automatic retrying of requests based on Tokens etc)
Now in your ViewController seperate all the handling of your data to a View-Independant LoginClass like this:
#IBAction func LoginButton(_ sender: UIButton) {
guard let username = usernameField.text else { print("no username") ; return }
guard let password = passwordField.text else { print("no password") ; return }
self.loginModel.login(username: username, password: password) { [weak self] success in
if success {
let dataModel = dataModel(credentials: credentialStyle)
dataModel.loadItems { items : [Item]? in
// Dispatch items to main queue
}
}
}
}
Now in your loginModel you handle the login and in a completely separate model you handle the dataModel which you instantiate with the credentials you received from the loginModel. Off course this is a rough example and using Alamofire you can use a Session Manager for example which will take care of the authentication (see the URL of 'automatic retrying of requests', scroll down a little bit and there is an example of authentication.) removing the need of instantiating your dataModel with credentials put this is purely to demonstrate how to split up your code to handle these requests.