OIDExternalUserAgentIOSSafariViewController.h

/*! @file OIDExternalUserAgentIOSSafariViewController.h
    @brief AppAuth iOS SDK
    @copyright
        Copyright 2018 Google Inc. All Rights Reserved.
    @copydetails
        Licensed under the Apache License, Version 2.0 (the "License");
        you may not use this file except in compliance with the License.
        You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

        Unless required by applicable law or agreed to in writing, software
        distributed under the License is distributed on an "AS IS" BASIS,
        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
        See the License for the specific language governing permissions and
        limitations under the License.
 */

#import <UIKit/UIKit.h>

#import "OIDExternalUserAgentIOSSafariViewController.h"
#import "OIDExternalUserAgent.h"
#import "OIDExternalUserAgentIOS.h"

NS_ASSUME_NONNULL_BEGIN

/*! @brief Allows library consumers to bootstrap an @c SFSafariViewController as they see fit.
    @remarks Useful for customizing tint colors and presentation styles.
 */
@protocol OIDSafariViewControllerFactory

/*! @brief Creates and returns a new @c SFSafariViewController.
    @param URL The URL which the @c SFSafariViewController should load initially.
 */
- (SFSafariViewController *)safariViewControllerWithURL:(NSURL *)URL;

@end

/*! @brief A special-case iOS external user-agent that always uses 
        \SFSafariViewController (on iOS 9+). Most applications should use
        the more generic @c OIDExternalUserAgentIOS to get the default
        AppAuth user-agent handling with the benefits of Single Sign-on (SSO)
        for all supported versions of iOS.
 */
@interface OIDExternalUserAgentIOSSafariViewController : NSObject<OIDExternalUserAgent>

/*! @brief Allows library consumers to change the @c OIDSafariViewControllerFactory used to create
        new instances of @c SFSafariViewController.
    @remarks Useful for customizing tint colors and presentation styles.
    @param factory The @c OIDSafariViewControllerFactory to use for creating new instances of
        @c SFSafariViewController.
 */
+ (void)setSafariViewControllerFactory:(id<OIDSafariViewControllerFactory>)factory;

/*! @internal
    @brief Unavailable. Please use @c initWithPresentingViewController:
 */
- (nonnull instancetype)init NS_UNAVAILABLE;

/*! @brief The designated initializer.
    @param presentingViewController The view controller from which to present the
        \SFSafariViewController.
 */
- (nullable instancetype)initWithPresentingViewController:
    (UIViewController *)presentingViewController
    NS_DESIGNATED_INITIALIZER;

@end

NS_ASSUME_NONNULL_END

OIDExternalUserAgentIOSSafariViewController.m

/*! @file OIDExternalUserAgentIOSSafariViewController.m
    @brief AppAuth iOS SDK
    @copyright
        Copyright 2018 Google Inc. All Rights Reserved.
    @copydetails
        Licensed under the Apache License, Version 2.0 (the "License");
        you may not use this file except in compliance with the License.
        You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

        Unless required by applicable law or agreed to in writing, software
        distributed under the License is distributed on an "AS IS" BASIS,
        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
        See the License for the specific language governing permissions and
        limitations under the License.
 */

#import "OIDExternalUserAgentIOSSafariViewController.h"

#import <SafariServices/SafariServices.h>

#import "OIDErrorUtilities.h"
#import "OIDExternalUserAgentSession.h"
#import "OIDExternalUserAgentRequest.h"

NS_ASSUME_NONNULL_BEGIN

/** @brief The global/shared Safari view controller factory. Responsible for creating all new
 instances of @c SFSafariViewController.
 */
static id<OIDSafariViewControllerFactory> __nullable gSafariViewControllerFactory;

/** @brief The default @c OIDSafariViewControllerFactory which creates new instances of
        @c SFSafariViewController using known best practices.
 */
@interface OIDDefaultSafariViewControllerFactory : NSObject<OIDSafariViewControllerFactory>
@end

@interface OIDExternalUserAgentIOSSafariViewController ()<SFSafariViewControllerDelegate>
@end

@implementation OIDExternalUserAgentIOSSafariViewController {
  UIViewController *_presentingViewController;

  BOOL _externalUserAgentFlowInProgress;
  __weak id<OIDExternalUserAgentSession> _session;
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wpartial-availability"
  __weak SFSafariViewController *_safariVC;
#pragma clang diagnostic pop
}

/** @brief Obtains the current @c OIDSafariViewControllerFactory; creating a new default instance if
        required.
 */
+ (id<OIDSafariViewControllerFactory>)safariViewControllerFactory {
  if (!gSafariViewControllerFactory) {
    gSafariViewControllerFactory = [[OIDDefaultSafariViewControllerFactory alloc] init];
  }
  return gSafariViewControllerFactory;
}

 + (void)setSafariViewControllerFactory:(id<OIDSafariViewControllerFactory>)factory {
  NSAssert(factory, @"Parameter: |factory| must be non-nil.");
  gSafariViewControllerFactory = factory;
}

- (nullable instancetype)initWithPresentingViewController:
        (UIViewController *)presentingViewController {
  self = [super init];
  if (self) {
    _presentingViewController = presentingViewController;
  }
  return self;
}

- (BOOL)presentExternalUserAgentRequest:(id<OIDExternalUserAgentRequest>)request
                                session:(id<OIDExternalUserAgentSession>)session {
  if (_externalUserAgentFlowInProgress) {
    // TODO: Handle errors as authorization is already in progress.
    return NO;
  }

  _externalUserAgentFlowInProgress = YES;
  _session = session;
  BOOL openedSafari = NO;
  NSURL *requestURL = [request externalUserAgentRequestURL];

  if (@available(iOS 9.0, *)) {
    SFSafariViewController *safariVC =
        [[[self class] safariViewControllerFactory] safariViewControllerWithURL:requestURL];
      safariVC.delegate = self;
      _safariVC = safariVC;
      [_presentingViewController presentViewController:safariVC animated:YES completion:nil];
      openedSafari = YES;
  } else {
    openedSafari = [[UIApplication sharedApplication] openURL:requestURL];
  }

  if (!openedSafari) {
    [self cleanUp];
    NSError *safariError = [OIDErrorUtilities errorWithCode:OIDErrorCodeSafariOpenError
                                            underlyingError:nil
                                                description:@"Unable to open Safari."];
    [session failExternalUserAgentFlowWithError:safariError];
  }
  return openedSafari;
}

- (void)dismissExternalUserAgentAnimated:(BOOL)animated completion:(void (^)(void))completion {
  if (!_externalUserAgentFlowInProgress) {
    // Ignore this call if there is no authorization flow in progress.
    return;
  }
  
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wpartial-availability"
  SFSafariViewController *safariVC = _safariVC;
#pragma clang diagnostic pop
  
  [self cleanUp];
  
  if (@available(iOS 9.0, *)) {
    if (safariVC) {
      [safariVC dismissViewControllerAnimated:YES completion:completion];
    } else {
      if (completion) completion();
    }
  } else {
    if (completion) completion();
  }
}

- (void)cleanUp {
  // The weak references to |_safariVC| and |_session| are set to nil to avoid accidentally using
  // them while not in an authorization flow.
  _safariVC = nil;
  _session = nil;
  _externalUserAgentFlowInProgress = NO;
}

#pragma mark - SFSafariViewControllerDelegate

- (void)safariViewControllerDidFinish:(SFSafariViewController *)controller NS_AVAILABLE_IOS(9.0) {
  if (controller != _safariVC) {
    // Ignore this call if the safari view controller do not match.
    return;
  }
  if (!_externalUserAgentFlowInProgress) {
    // Ignore this call if there is no authorization flow in progress.
    return;
  }
  id<OIDExternalUserAgentSession> session = _session;
  [self cleanUp];
  NSError *error = [OIDErrorUtilities errorWithCode:OIDErrorCodeProgramCanceledAuthorizationFlow
                                    underlyingError:nil
                                        description:nil];
  [session failExternalUserAgentFlowWithError:error];
}

@end

@implementation OIDDefaultSafariViewControllerFactory

- (SFSafariViewController *)safariViewControllerWithURL:(NSURL *)URL NS_AVAILABLE_IOS(9.0) {
  SFSafariViewController *safariViewController =
      [[SFSafariViewController alloc] initWithURL:URL entersReaderIfAvailable:NO];
  return safariViewController;
}

@end

NS_ASSUME_NONNULL_END

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Hi @WilliamDennis,

In dismissExternalUserAgentAnimated , you're calling cleanUp method before dismissing the safariVC. So the safariVC will never get dismissed.

We need to call cleanUp after the dismissal of safariVC.

thanks!