Swift - Multiple Parameters to webservice - ios

Question

I have the following code that should send a username and password off to a webservice, in return I get a single integer back:
func attemptLogin() {
let url:URL = URL(string: endpoint+"/LoginNew")!
let session = URLSession.shared
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.cachePolicy = NSURLRequest.CachePolicy.reloadIgnoringCacheData
let postString = "username="+txtUsername.text! + "; password="+txtPassword.text!
request.httpBody = postString.data(using: String.Encoding.utf8)
let task = session.dataTask(with: request as URLRequest) {
(
data, response, error) in
guard let data = data, let _:URLResponse = response, error == nil else {
print("error")
return
}
let dataString = String(data: data, encoding: String.Encoding.utf8)
print(dataString)
}
task.resume()
}
In my function I need to add two parameters are I'm trying to do in this line:
let postString = "username="+txtUsername.text! + "; password="+txtPassword.text!
request.httpBody = postString.data(using: String.Encoding.utf8)
I am getting the following response from my web service when I run this however
Optional("Missing parameter: password.\r\n")
I am obviously not appending the parameters to the request properly but I'm not sure what I've done wrong.

Answer 1

It is good practice to avoid using explicit unwraps of optionals (using !), use guard let for text i UITextFields instead.
And why not separate into two methods, attemptLogin and login, which maybe can take a closure for code to execute when sign in completed? Maybe the closure can take an Result enum.
Like this:
typealias Done = (Result) -> Void
enum MyError: Error {
case unknown
}
enum Result {
case success(String)
case failure(MyError)
init(_ error: MyError) {
self = .failure(error)
}
init(_ dataString: String) {
self = .success(dataString)
}
}
func login(username: String, password: String, done: Done? = nil) {
let session = URLSession.shared
guard
let url = URL(string: endpoint+"/LoginNew"),
else { return }
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.cachePolicy = NSURLRequest.CachePolicy.reloadIgnoringCacheData
let postString = "username=\(username)&password=\(password)"
request.httpBody = postString.data(using: String.Encoding.utf8)
let task = session.dataTask(with: request) {
(data, response, error) in
guard let data = data else { done?(Result(.unknown)); return }
let dataString = String(data: data, encoding: String.Encoding.utf8)
done?(Result(dataString))
}
task.resume()
}
func attemptLogin() {
guard
let username = txtUsername.text,
let password = txtPassword.text
else { return }
login(username: username, password: password) {
result in
swicth result {
case .success(let dataString):
print(dataString)
case .failure(let error):
print("Failed with error: \(error)")
}
}
}
Disclaimer: Have not tested the code above, but hopefully it compiles (at least with very small changes).