Improve iOS error handling (#654)

* Fix an error handling case

* Pull 'error_description' from userInfo dictionary provided by AppAuth-iOS

Author: pond

ios/RNAppAuth.m

@@ -35,7 +35,7 @@ - (dispatch_queue_t)methodQueue
 static NSUInteger const kCodeVerifierBytes = 32;
 
 RCT_EXPORT_MODULE()
-    
+
 RCT_REMAP_METHOD(register,
                  issuer: (NSString *) issuer
                  redirectUrls: (NSArray *) redirectUrls
@@ -221,7 +221,7 @@ + (nullable NSString *)codeChallengeS256ForVerifier:(NSString *)codeVerifier {
   return [OIDTokenUtilities encodeBase64urlNoPadding:sha256Verifier];
 }
 
-    
+
 /*
  * Perform dynamic client registration with provided OIDServiceConfiguration
  */
@@ -239,7 +239,7 @@ - (void)registerWithConfiguration: (OIDServiceConfiguration *) configuration
     for (NSString *urlString in redirectUrlStrings) {
         [redirectUrls addObject:[NSURL URLWithString:urlString]];
     }
-    
+
     OIDRegistrationRequest *request =
     [[OIDRegistrationRequest alloc] initWithConfiguration:configuration
                                              redirectURIs:redirectUrls
@@ -248,19 +248,19 @@ - (void)registerWithConfiguration: (OIDServiceConfiguration *) configuration
                                               subjectType:subjectType
                                   tokenEndpointAuthMethod:tokenEndpointAuthMethod
                                      additionalParameters:additionalParameters];
-    
+
     [OIDAuthorizationService performRegistrationRequest:request
                                              completion:^(OIDRegistrationResponse *_Nullable response,
                                                           NSError *_Nullable error) {
                                                  if (response) {
                                                      resolve([self formatRegistrationResponse:response]);
                                                  } else {
                                                      reject([self getErrorCode: error defaultCode:@"registration_failed"],
-                                                            [error localizedDescription], error);
+                                                            [self getErrorMessage: error], error);
                                                  }
                                             }];
 }
-    
+
 /*
  * Authorize a user in exchange for a token with provided OIDServiceConfiguration
  */
@@ -324,7 +324,7 @@ - (void)authorizeWithConfiguration: (OIDServiceConfiguration *) configuration
                                                            resolve([self formatAuthorizationResponse:authorizationResponse withCodeVerifier:codeVerifier]);
                                                        } else {
                                                            reject([self getErrorCode: error defaultCode:@"authentication_failed"],
-                                                                  [error localizedDescription], error);
+                                                                  [self getErrorMessage: error], error);
                                                        }
                                                    }]; // end [OIDAuthState presentAuthorizationRequest:request
     } else {
@@ -340,7 +340,8 @@ - (void)authorizeWithConfiguration: (OIDServiceConfiguration *) configuration
                                                         resolve([self formatResponse:authState.lastTokenResponse
                                                             withAuthResponse:authState.lastAuthorizationResponse]);
                                                     } else {
-                                                        reject(@"authentication_failed", [error localizedDescription], error);
+                                                        reject([self getErrorCode: error defaultCode:@"authentication_failed"],
+                                                               [self getErrorMessage: error], error);
                                                     }
                                                 }]; // end [OIDAuthState authStateByPresentingAuthorizationRequest:request
     }
@@ -378,7 +379,7 @@ - (void)refreshWithConfiguration: (OIDServiceConfiguration *)configuration
                                                 resolve([self formatResponse:response]);
                                             } else {
                                                 reject([self getErrorCode: error defaultCode:@"token_refresh_failed"],
-                                                       [error localizedDescription], error);
+                                                       [self getErrorMessage: error], error);
                                             }
                                         }];
 }
@@ -389,7 +390,7 @@ - (void) configureUrlSession: (NSDictionary*) headers {
     if (headers != nil) {
         configuration.HTTPAdditionalHeaders = headers;
     }
-    
+
     NSURLSession* session = [NSURLSession sessionWithConfiguration:configuration];
     [OIDURLSessionProvider setSession:session];
 }
@@ -466,13 +467,13 @@ - (NSDictionary*)formatResponse: (OIDTokenResponse*) response
              @"scopes": authResponse.scope ? [authResponse.scope componentsSeparatedByString:@" "] : [NSArray new],
              };
 }
-    
+
 - (NSDictionary*)formatRegistrationResponse: (OIDRegistrationResponse*) response {
     NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
     dateFormat.timeZone = [NSTimeZone timeZoneWithAbbreviation: @"UTC"];
     [dateFormat setLocale:[NSLocale localeWithLocaleIdentifier:@"en_US_POSIX"]];
     [dateFormat setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss'Z'"];
-    
+
     return @{@"clientId": response.clientID,
              @"additionalParameters": response.additionalParameters,
              @"clientIdIssuedAt": response.clientIDIssuedAt ? [dateFormat stringFromDate:response.clientIDIssuedAt] : @"",
@@ -531,4 +532,16 @@ - (NSString*)getErrorCode: (NSError*) error defaultCode: (NSString *) defaultCod
     return defaultCode;
 }
 
+- (NSString*)getErrorMessage: (NSError*) error {
+    NSDictionary * userInfo = [error userInfo];
+
+    if (userInfo &&
+        userInfo[OIDOAuthErrorResponseErrorKey] &&
+        userInfo[OIDOAuthErrorResponseErrorKey][OIDOAuthErrorFieldErrorDescription]) {
+        return userInfo[OIDOAuthErrorResponseErrorKey][OIDOAuthErrorFieldErrorDescription];
+    } else {
+        return [error localizedDescription];
+    }
+}
+
 @end