GoogleSignIn-Swift

Minimalistic Google Sign In oAuth 2.0 client written in Swift

GoogleSignIn-Swift is compatible with Swift Package Manager. You can add it as a dependency to your Xcode project by following official documentation.

1. You will need to configure Google oAuth 2.0 client

   1. Go to Google API Console
   2. Create new project or choose existing one
   3. On "Credentials" page, choose "Create credentials ➔ oAuth Client ID"
   4. Choose "Other" as a Application Type

2. In your project create GoogleSignIn.Controller instance

   import GoogleSignIn
   
   let controller = GoogleSignIn.Controller(
       config: GoogleSignIn.Config(
           clientId: "CLIENT_ID",
           clientSecret: "CLIENT_SECRET",
           redirectUri: "REDIRECT_URI"
       ),
       session: URLSession.shared
   )

   You can obtain CLIENT_ID and CLIENT_SECRET from Google API Console.

   REDIRECT_URI is your CLIENT_ID with reverse domain notation and :// suffix. For example:

   • client id: 1234-abcd.apps.googleusercontent.com
   • reversed client id: com.googleusercontent.apps.1234-abcd
   • redirect uri: com.googleusercontent.apps.1234-abcd://

3. Implement presenting sign in page to the user, by opening signInPageURL provided by the controller.

   It can vary depending on the type of the app you are working on. The simpliest way to do it in iOS app is by using UIApplication.open(_ url:):

   UIApplication.shared.open(controller.signInPageURL)

4. Configure your application, so it can handle redirect after sign in.

   For iOS app, you can do it by adding or modifying CFBundleURLTypes in Info.plist:

   <key>CFBundleURLTypes</key>
   <array>
       <dict>
           <key>CFBundleTypeRole</key>
           <string>Editor</string>
           <key>CFBundleURLName</key>
           <string></string>
           <key>CFBundleURLSchemes</key>
           <array>
               <string>REDIRECT_URI_SCHEME</string>
           </array>
       </dict>
   </array>
   

   Replace REDIRECT_URI_SCHEME with your CLIENT_ID using reverse domain notation. For example: com.googleusercontent.apps.1234-abcd.

5. Handle redirection after user signs in to obtain oAuth tokens (access, ID and refresh) by calling getTokenResponse function on GoogleSignIn.Controller.

   For iOS app, you can do it by implementing this function in your UIApplicationDelegate:

   func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
       controller.getTokenResponse(using: url) { result in
           if case let .success(response) = result {
               print("ACCESS TOKEN: \(response.accessToken)")
           }
       }
       return true
   }

   If you are using UIWindowSceneDelegate in your app, implement this function instead:

   func scene(_ scene: UIScene, openURLContexts contexts: Set<UIOpenURLContext>) {
       guard let redirectUrl = contexts.first?.url else { return }
       controller.getTokenResponse(using: redirectUrl) { result in
           if case let .success(response) = result {
               print("ACCESS TOKEN: \(response.accessToken)")
           }
       }
   }

6. Do whatever you want with obtained access token.

Copyright © 2019 Dariusz Rybicki Darrarski

License: GNU GPLv3