Can I use google drive sdk with authentication info from google sign-in sdk on iOS?

Question

We already have a login module uses Google Sign-In sdk. Google Sign-In gives a GIDAuthentication object after login succeed.

Now I want to access user\'s google dri

Answer 1

Yes you can!

Use the following steps:

1. Follow all the steps to add Google SignIn as described in: https://developers.google.com/identity/sign-in/ios/start-integrating. Make sure you enable the Google Drive API for your project.

2. When initialising the sign-in object, don't forget to add the Google Drive API scope:

   func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
       // Initialize sign-in
       var configureError: NSError?
       GGLContext.sharedInstance().configureWithError(&configureError)
       assert(configureError == nil, "Error configuring Google services: \(configureError)")
   
       GIDSignIn.sharedInstance().delegate = self
   
       // Use here whatever auth scope you wish (e.g., kGTLAuthScopeDriveReadonly, 
       // kGTLAuthScopeDriveMetadata, etc..)
       // You can obviously append more scopes to allow access to more services,
       // other than Google Drive.
       GIDSignIn.sharedInstance().scopes.append(kGTLAuthScopeDrive)
   
       return true
   }
   

3. In your AppDelegate (or some other accessible place), add:

   var myAuth: GTMFetcherAuthorizationProtocol? = nil
   

4. In you signIn delegate function (assuming here it is also set in AppDelegate), add the following code:

   func signIn(signIn: GIDSignIn!, didSignInForUser user: GIDGoogleUser!, withError error: NSError!) {
       if (error == nil) {
           // Logged into google services successfully! 
           // Save relevant details from user.authentication to refresh the token when needed.      
   
           // Set GTMOAuth2Authentication authoriser for your Google Drive service
           myAuth = user.authentication.fetcherAuthorizer()
       } else {
           // Error signing into Google services
       }
   }
   

5. Last, wherever you set your GoogleServiceDrive, you can also set its authoriser, simply by setting:

   let service = GTLServiceDrive()
   service.authorizer = (UIApplication.sharedApplication().delegate as! AppDelegate).myAuth
   

6. Now you can use the example code by Google

   if let authorizer = service.authorizer, canAuth = authorizer.canAuthorize where canAuth {
       // service is authorised and can be used for queries
   } else {
       // service is not authorised 
   }