How to authenticate with the Box SDK using SwiftUI? - swift

Question

I have been having a hard time trying to figure out how to authenticate with the Box API using SwiftUI.
As far as I understand, SwiftUI does not currently have the ability to satisfy the ASWebAuthenticationPresentationContextProviding protocol required to show the Safari OAuth2 login sheet. I know that I can make a UIViewControllerRepresentable to use UIKit within SwiftUI, but I can't get this to work.

Answer 1

I have figured out how to get the OAuth2 login sheet for Dropbox to appear and authenticate the client using SwiftUI.
The trick is to use a Coordinator to make the UIViewControllerRepresentable satisfy a protocol.
import SwiftUI
import BoxSDK
import AuthenticationServices
var boxSDK = BoxSDK(clientId: "<Client ID>", clientSecret: "<Client Secret>")
var boxClient: BoxClient
struct BoxLoginView: View {
#State var showLogin = false
var body: some View {
VStack {
Button {
showLogin = true
} label: {
Text("Login")
}
BoxView(isShown: $showLogin)
// Arbitrary frame size so that this view does not take up the whole screen
.frame(width: 40, height: 40)
}
}
}
/// A UIViewController that will present the OAuth2 Safari login screen when the isShown is true.
struct BoxView: UIViewControllerRepresentable {
typealias UIViewControllerType = UIViewController
let letsView = UIViewController()
#Binding var isShown : Bool
// Show the login Safari window when isShown
func updateUIViewController(_ uiViewController: UIViewController, context: Context) {
if(isShown) {
getOAuthClient()
}
}
func makeUIViewController(context _: Self.Context) -> UIViewController {
return self.letsView
}
func makeCoordinator() -> Coordinator {
return Coordinator(parent: self)
}
func getOAuthClient() {
boxSDK.getOAuth2Client(tokenStore: KeychainTokenStore(), context:self.makeCoordinator()) { result in
switch result {
case let .success(client):
boxClient = client
case let .failure(error):
print("error in getOAuth2Client: \(error)")
}
}
}
class Coordinator: NSObject, ASWebAuthenticationPresentationContextProviding {
var parent: BoxView
init(parent: BoxView) {
self.parent = parent
}
func presentationAnchor(for session: ASWebAuthenticationSession) -> ASPresentationAnchor {
return parent.letsView.view.window ?? ASPresentationAnchor()
}
}
}