SFSafariViewController autologin snippets

SafariViewControllerAutlogin.m

// Say this is in your app delegate

- (void) attemptAutologin
{
    NSURL *autologinURL = ...some..url..that..does..autologin..on..your..server
    self.safariViewController = [[SFSafariViewController alloc] initWithURL:autologinURL];
    self.safariViewController.modalPresentationStyle = UIModalPresentationOverFullScreen;
    self.safariViewController.view.alpha = 0.0;
    [self.window.rootViewController presentViewController:self.safariViewController
                                                 animated:NO
                                               completion:nil];
    self.awaitingAutologinResponse = YES;
}

// Now, the page at 'autloginURL' will be written to check its
// cookies to see if the user is logged in, and then somehow your
// server will generate a one-time "token" that your iOS app can
// use to login as the same user that is logged in to the web.
//
// Then, the page will redirect back to your app (using a url handler
// that your app registered, or BETTER YET, a url that is registered
// using the apple-app-site-associations, so other apps can't "hijack"
// the same url your app wants to use and potentially get to the
// autologin token.
//
// Note that all of the above happens while SFSafariViewController is
// still being "presented" (but hidden), so the app doesn't actually
// switch over to the Safari app.

- (BOOL) application:(UIApplication *)application
             openURL:(NSURL *)url
   sourceApplication:(NSString *)sourceApplication
          annotation:(id)annotation
{
    NSDictionary *params = url.queryDictionary;

    // Your server might return it differently, but this is 
    self.autologinAuthToken = params[@"autologin_token"];

    if (self.safariViewController != nil) {
        [self.window.rootViewController dismissViewControllerAnimated:NO completion:^{
            if (self.awaitingAutologinResponse) {
                if (self.autologinAuthToken.length > 0) {
                    // Save this url for later, and try and authenticate first
                    // The url might have more information than just the autologin_token
                    self.pendingURLToOpen = url;
                    [self autologinWithClusterToken:self.autologinAuthToken];
                } else {
                    [self finishAutologinAttemptWithSuccess:NO error:nil];
                }
            }
        }];
        return YES;
    }
    
    // Handle other actual open url cases
    return NO;
}