Instagram login using ASWebAuthenticationSession

I am currently using the ability to log in with my Instagram account using ASWebAuthenticationSession and it is not working!

I filled in the URL directly and there was no problem on the web, but when I run it in SwiftUI in Xcode, it doesn't work and Error: The operation couldn’t be completed. (com.apple.AuthenticationServices.WebAuthenticationSession error 2.) I get this error.

I was told that I need a custom scheme to return to mobile, but the Instagram redirect URL says no custom scheme.

What should I do?

IDs and URLs are placed under assumption.

I have no idea since this is my first implementation. Should I send the scheme URL from the website to mobile once using Django or something else?

import SwiftUI
import AuthenticationServices

struct InstagramLoginView: View {
   @State private var authSession: ASWebAuthenticationSession?
   @State private var token: String = ""
   @State private var showAlert: Bool = false
   @State private var alertMessage: String = ""
   
   var body: some View {
       VStack {
           Text("Instagram Login")
               .font(.largeTitle)
               .padding()
           
           Button(action: {
               startInstagramLogin()
           }) {
               Text("Login with Instagram")
                   .padding()
                   .background(Color.blue)
                   .foregroundColor(.white)
                   .cornerRadius(10)
           }
           
           if !token.isEmpty {
               Text("Token: \(token)")
                   .padding()
           }
       }
       .alert(isPresented: $showAlert) {
           Alert(title: Text("Error"), message: Text(alertMessage), dismissButton: .default(Text("OK")))
       }
   }
   
   func startInstagramLogin() {
       let clientID = "XXXXXXXXXX" // Instagram client ID
       let redirectURI = "https://example.com" // Instagram Redirect URI
       
       guard let authURL = URL(string: "https://api.instagram.com/oauth/authorize?client_id=\(clientID)&redirect_uri=\(redirectURI)&scope=user_profile,user_media&response_type=code") else {
           print("Invalid URL")
           return
       }
       
       authSession = ASWebAuthenticationSession(url: authURL, callbackURLScheme: "customscheme") { callbackURL, error in
           if let error = error {
               print("Error: \(error.localizedDescription)")
               return
           }
           
           guard let callbackURL = callbackURL else {
               print("Invalid callback URL")
               return
           }
           
           if let code = URLComponents(string: callbackURL.absoluteString)?.queryItems?.first(where: { $0.name == "code" })?.value {
               print("Authorization code: \(code)")
     
               getInstagramAccessToken(authCode: code)
           }
       }
       authSession?.start()
   }
   func getInstagramAccessToken(authCode: String) {
       let tokenURL = "https://api.instagram.com/oauth/access_token"
       var request = URLRequest(url: URL(string: tokenURL)!)
       request.httpMethod = "POST"
       let clientID = "XXXXXXXXXXXX"
       let clientSecret = "XXXXXXXXXXXXXX" // Instagram clientSecret
       let redirectURI = "https://example.com/"
       
       let params = "client_id=\(clientID)&client_secret=\(clientSecret)&grant_type=authorization_code&redirect_uri=\(redirectURI)&code=\(authCode)"
       request.httpBody = params.data(using: .utf8)
       request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
       
       URLSession.shared.dataTask(with: request) { data, response, error in
           if let error = error {
               print("Error: \(error.localizedDescription)")
               return
           }
           
           guard let data = data else {
               print("No data")
               return
           }
           
           if let jsonResponse = try? JSONSerialization.jsonObject(with: data, options: []) as? [String: Any],
              let accessToken = jsonResponse["access_token"] as? String {
               print("Access Token: \(accessToken)")
               // ここでアクセストークンを使用してInstagram APIにアクセスする
           } else {
               print("Failed to get access token")
           }
       }.resume()
   }

}

#Preview {
   InstagramLoginView()
}