Add shouldFallBack to requestController protocol

Author: kai

IdentityCore/src/controllers/MSIDLocalInteractiveController.m

@@ -242,4 +242,9 @@ - (void)acquireTokenWithRequest:(MSIDInteractiveTokenRequest *)request
     }];
 }
 
+- (BOOL)shouldFallback:(NSError *)error
+{
+    return YES;
+}
+
 @end

IdentityCore/src/controllers/MSIDRequestControlling.h

@@ -31,6 +31,7 @@ NS_ASSUME_NONNULL_BEGIN
 @protocol MSIDRequestControlling <NSObject>
 
 - (void)acquireToken:(nonnull MSIDRequestCompletionBlock)completionBlock;
+- (BOOL)shouldFallback:(nonnull NSError *)error;
 
 @end
 

IdentityCore/src/controllers/MSIDSilentController.m

@@ -158,4 +158,9 @@ - (void)acquireTokenWithRequest:(MSIDSilentTokenRequest *)request
     }];
 }
 
+- (BOOL)shouldFallback:(NSError *)error
+{
+    return YES;
+}
+
 @end

IdentityCore/src/controllers/broker/MSIDSSOExtensionSilentTokenRequestController.m

@@ -49,5 +49,33 @@ + (BOOL)canPerformRequest
     return [[ASAuthorizationSingleSignOnProvider msidSharedProvider] canPerformAuthorization];
 }
 
+- (BOOL)shouldFallback:(NSError *)error
+{
+    MSID_LOG_WITH_CTX(MSIDLogLevelInfo, self.requestParameters, @"Looking if we should fallback to fallback controller, error: %ld error domain: %@.", (long)error.code, error.domain);
+    
+    if (!self.fallbackController)
+    {
+        MSID_LOG_WITH_CTX(MSIDLogLevelInfo, self.requestParameters, @"fallback controller is nil, SSO extension controller should fallback: NO");
+        return NO;
+    }
+    
+    // If it is MSIDErrorDomain and Sso Extension returns unexpected error, we should fall back to local controler and unblock user
+    if (![error.domain isEqualToString:ASAuthorizationErrorDomain] && ![error.domain isEqualToString:MSIDErrorDomain]) return NO;
+    
+    BOOL shouldFallback = NO;
+    switch (error.code)
+    {
+        case ASAuthorizationErrorNotHandled:
+        case ASAuthorizationErrorUnknown:
+        case ASAuthorizationErrorFailed:
+        case MSIDErrorSSOExtensionUnexpectedError:
+            shouldFallback = YES;
+    }
+    
+    MSID_LOG_WITH_CTX(MSIDLogLevelInfo, self.requestParameters, @"SSO extension controller should fallback: %@", shouldFallback ? @"YES" : @"NO");
+    
+    return shouldFallback;
+}
+
 @end
 #endif