diff options
Diffstat (limited to 'Firebase/Utilities/Network/GULNetworkURLSession.m')
| -rw-r--r-- | Firebase/Utilities/Network/GULNetworkURLSession.m | 669 |
1 files changed, 669 insertions, 0 deletions
diff --git a/Firebase/Utilities/Network/GULNetworkURLSession.m b/Firebase/Utilities/Network/GULNetworkURLSession.m new file mode 100644 index 0000000..cb8a204 --- /dev/null +++ b/Firebase/Utilities/Network/GULNetworkURLSession.m @@ -0,0 +1,669 @@ +// Copyright 2017 Google +// +// 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 <Foundation/Foundation.h> + +#import "Private/GULNetworkURLSession.h" + +#import <GoogleUtilities/GULLogger.h> +#import "Private/GULMutableDictionary.h" +#import "Private/GULNetworkConstants.h" +#import "Private/GULNetworkMessageCode.h" + +@implementation GULNetworkURLSession { + /// The handler to be called when the request completes or error has occurs. + GULNetworkURLSessionCompletionHandler _completionHandler; + + /// Session ID generated randomly with a fixed prefix. + NSString *_sessionID; + + /// The session configuration. + NSURLSessionConfiguration *_sessionConfig; + + /// The path to the directory where all temporary files are stored before uploading. + NSURL *_networkDirectoryURL; + + /// The downloaded data from fetching. + NSData *_downloadedData; + + /// The path to the temporary file which stores the uploading data. + NSURL *_uploadingFileURL; + + /// The current request. + NSURLRequest *_request; +} + +#pragma mark - Init + +- (instancetype)initWithNetworkLoggerDelegate:(id<GULNetworkLoggerDelegate>)networkLoggerDelegate { + self = [super init]; + if (self) { + // Create URL to the directory where all temporary files to upload have to be stored. + NSArray *paths = + NSSearchPathForDirectoriesInDomains(NSApplicationSupportDirectory, NSUserDomainMask, YES); + NSString *applicationSupportDirectory = paths.firstObject; + NSArray *tempPathComponents = @[ + applicationSupportDirectory, kGULNetworkApplicationSupportSubdirectory, + kGULNetworkTempDirectoryName + ]; + _networkDirectoryURL = [NSURL fileURLWithPathComponents:tempPathComponents]; + _sessionID = [NSString stringWithFormat:@"%@-%@", kGULNetworkBackgroundSessionConfigIDPrefix, + [[NSUUID UUID] UUIDString]]; + _loggerDelegate = networkLoggerDelegate; + } + return self; +} + +#pragma mark - External Methods + +#pragma mark - To be called from AppDelegate + ++ (void)handleEventsForBackgroundURLSessionID:(NSString *)sessionID + completionHandler: + (GULNetworkSystemCompletionHandler)systemCompletionHandler { + // The session may not be Analytics background. Ignore those that do not have the prefix. + if (![sessionID hasPrefix:kGULNetworkBackgroundSessionConfigIDPrefix]) { + return; + } + GULNetworkURLSession *fetcher = [self fetcherWithSessionIdentifier:sessionID]; + if (fetcher != nil) { + [fetcher addSystemCompletionHandler:systemCompletionHandler forSession:sessionID]; + } else { + GULLogError(kGULLoggerNetwork, NO, + [NSString stringWithFormat:@"I-NET%06ld", (long)kGULNetworkMessageCodeNetwork003], + @"Failed to retrieve background session with ID %@ after app is relaunched.", + sessionID); + } +} + +#pragma mark - External Methods + +/// Sends an async POST request using NSURLSession for iOS >= 7.0, and returns an ID of the +/// connection. +- (NSString *)sessionIDFromAsyncPOSTRequest:(NSURLRequest *)request + completionHandler:(GULNetworkURLSessionCompletionHandler)handler { + // NSURLSessionUploadTask does not work with NSData in the background. + // To avoid this issue, write the data to a temporary file to upload it. + // Make a temporary file with the data subset. + _uploadingFileURL = [self temporaryFilePathWithSessionID:_sessionID]; + NSError *writeError; + NSURLSessionUploadTask *postRequestTask; + NSURLSession *session; + BOOL didWriteFile = NO; + + // Clean up the entire temp folder to avoid temp files that remain in case the previous session + // crashed and did not clean up. + [self maybeRemoveTempFilesAtURL:_networkDirectoryURL + expiringTime:kGULNetworkTempFolderExpireTime]; + + // If there is no background network enabled, no need to write to file. This will allow default + // network session which runs on the foreground. + if (_backgroundNetworkEnabled && [self ensureTemporaryDirectoryExists]) { + didWriteFile = [request.HTTPBody writeToFile:_uploadingFileURL.path + options:NSDataWritingAtomic + error:&writeError]; + + if (writeError) { + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession000 + message:@"Failed to write request data to file" + context:writeError]; + } + } + + if (didWriteFile) { + // Exclude this file from backing up to iTunes. There are conflicting reports that excluding + // directory from backing up does not excluding files of that directory from backing up. + [self excludeFromBackupForURL:_uploadingFileURL]; + + _sessionConfig = [self backgroundSessionConfigWithSessionID:_sessionID]; + [self populateSessionConfig:_sessionConfig withRequest:request]; + session = [NSURLSession sessionWithConfiguration:_sessionConfig + delegate:self + delegateQueue:[NSOperationQueue mainQueue]]; + postRequestTask = [session uploadTaskWithRequest:request fromFile:_uploadingFileURL]; + } else { + // If we cannot write to file, just send it in the foreground. + _sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration]; + [self populateSessionConfig:_sessionConfig withRequest:request]; + _sessionConfig.URLCache = nil; + session = [NSURLSession sessionWithConfiguration:_sessionConfig + delegate:self + delegateQueue:[NSOperationQueue mainQueue]]; + postRequestTask = [session uploadTaskWithRequest:request fromData:request.HTTPBody]; + } + + if (!session || !postRequestTask) { + NSError *error = [[NSError alloc] + initWithDomain:kGULNetworkErrorDomain + code:GULErrorCodeNetworkRequestCreation + userInfo:@{kGULNetworkErrorContext : @"Cannot create network session"}]; + [self callCompletionHandler:handler withResponse:nil data:nil error:error]; + return nil; + } + + // Save the session into memory. + NSMapTable *sessionIdentifierToFetcherMap = [[self class] sessionIDToFetcherMap]; + [sessionIdentifierToFetcherMap setObject:self forKey:_sessionID]; + + _request = [request copy]; + + // Store completion handler because background session does not accept handler block but custom + // delegate. + _completionHandler = [handler copy]; + [postRequestTask resume]; + + return _sessionID; +} + +/// Sends an async GET request using NSURLSession for iOS >= 7.0, and returns an ID of the session. +- (NSString *)sessionIDFromAsyncGETRequest:(NSURLRequest *)request + completionHandler:(GULNetworkURLSessionCompletionHandler)handler { + if (_backgroundNetworkEnabled) { + _sessionConfig = [self backgroundSessionConfigWithSessionID:_sessionID]; + } else { + _sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration]; + } + + [self populateSessionConfig:_sessionConfig withRequest:request]; + + // Do not cache the GET request. + _sessionConfig.URLCache = nil; + + NSURLSession *session = [NSURLSession sessionWithConfiguration:_sessionConfig + delegate:self + delegateQueue:[NSOperationQueue mainQueue]]; + NSURLSessionDownloadTask *downloadTask = [session downloadTaskWithRequest:request]; + + if (!session || !downloadTask) { + NSError *error = [[NSError alloc] + initWithDomain:kGULNetworkErrorDomain + code:GULErrorCodeNetworkRequestCreation + userInfo:@{kGULNetworkErrorContext : @"Cannot create network session"}]; + [self callCompletionHandler:handler withResponse:nil data:nil error:error]; + return nil; + } + + // Save the session into memory. + NSMapTable *sessionIdentifierToFetcherMap = [[self class] sessionIDToFetcherMap]; + [sessionIdentifierToFetcherMap setObject:self forKey:_sessionID]; + + _request = [request copy]; + + _completionHandler = [handler copy]; + [downloadTask resume]; + + return _sessionID; +} + +#pragma mark - NSURLSessionTaskDelegate + +/// Called by the NSURLSession once the download task is completed. The file is saved in the +/// provided URL so we need to read the data and store into _downloadedData. Once the session is +/// completed, URLSession:task:didCompleteWithError will be called and the completion handler will +/// be called with the downloaded data. +- (void)URLSession:(NSURLSession *)session + downloadTask:(NSURLSessionDownloadTask *)task + didFinishDownloadingToURL:(NSURL *)url { + if (!url.path) { + [_loggerDelegate + GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession001 + message:@"Unable to read downloaded data from empty temp path"]; + _downloadedData = nil; + return; + } + + NSError *error; + _downloadedData = [NSData dataWithContentsOfFile:url.path options:0 error:&error]; + + if (error) { + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession002 + message:@"Cannot read the content of downloaded data" + context:error]; + _downloadedData = nil; + } +} + +#if TARGET_OS_IOS || TARGET_OS_TV +- (void)URLSessionDidFinishEventsForBackgroundURLSession:(NSURLSession *)session { + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelDebug + messageCode:kGULNetworkMessageCodeURLSession003 + message:@"Background session finished" + context:session.configuration.identifier]; + [self callSystemCompletionHandler:session.configuration.identifier]; +} +#endif + +- (void)URLSession:(NSURLSession *)session + task:(NSURLSessionTask *)task + didCompleteWithError:(NSError *)error { + // Avoid any chance of recursive behavior leading to it being used repeatedly. + GULNetworkURLSessionCompletionHandler handler = _completionHandler; + _completionHandler = nil; + + if (task.response) { + // The following assertion should always be true for HTTP requests, see https://goo.gl/gVLxT7. + NSAssert([task.response isKindOfClass:[NSHTTPURLResponse class]], @"URL response must be HTTP"); + + // The server responded so ignore the error created by the system. + error = nil; + } else if (!error) { + error = [[NSError alloc] + initWithDomain:kGULNetworkErrorDomain + code:GULErrorCodeNetworkInvalidResponse + userInfo:@{kGULNetworkErrorContext : @"Network Error: Empty network response"}]; + } + + [self callCompletionHandler:handler + withResponse:(NSHTTPURLResponse *)task.response + data:_downloadedData + error:error]; + + // Remove the temp file to avoid trashing devices with lots of temp files. + [self removeTempItemAtURL:_uploadingFileURL]; + + // Try to clean up stale files again. + [self maybeRemoveTempFilesAtURL:_networkDirectoryURL + expiringTime:kGULNetworkTempFolderExpireTime]; +} + +- (void)URLSession:(NSURLSession *)session + task:(NSURLSessionTask *)task + didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge + completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, + NSURLCredential *credential))completionHandler { + // The handling is modeled after GTMSessionFetcher. + if ([challenge.protectionSpace.authenticationMethod + isEqualToString:NSURLAuthenticationMethodServerTrust]) { + SecTrustRef serverTrust = challenge.protectionSpace.serverTrust; + if (serverTrust == NULL) { + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelDebug + messageCode:kGULNetworkMessageCodeURLSession004 + message:@"Received empty server trust for host. Host" + context:_request.URL]; + completionHandler(NSURLSessionAuthChallengePerformDefaultHandling, nil); + return; + } + NSURLCredential *credential = [NSURLCredential credentialForTrust:serverTrust]; + if (!credential) { + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelWarning + messageCode:kGULNetworkMessageCodeURLSession005 + message:@"Unable to verify server identity. Host" + context:_request.URL]; + completionHandler(NSURLSessionAuthChallengeCancelAuthenticationChallenge, nil); + return; + } + + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelDebug + messageCode:kGULNetworkMessageCodeURLSession006 + message:@"Received SSL challenge for host. Host" + context:_request.URL]; + + void (^callback)(BOOL) = ^(BOOL allow) { + if (allow) { + completionHandler(NSURLSessionAuthChallengeUseCredential, credential); + } else { + [self->_loggerDelegate + GULNetwork_logWithLevel:kGULNetworkLogLevelDebug + messageCode:kGULNetworkMessageCodeURLSession007 + message:@"Cancelling authentication challenge for host. Host" + context:self->_request.URL]; + completionHandler(NSURLSessionAuthChallengeCancelAuthenticationChallenge, nil); + } + }; + + // Retain the trust object to avoid a SecTrustEvaluate() crash on iOS 7. + CFRetain(serverTrust); + + // Evaluate the certificate chain. + // + // The delegate queue may be the main thread. Trust evaluation could cause some + // blocking network activity, so we must evaluate async, as documented at + // https://developer.apple.com/library/ios/technotes/tn2232/ + dispatch_queue_t evaluateBackgroundQueue = + dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); + + dispatch_async(evaluateBackgroundQueue, ^{ + SecTrustResultType trustEval = kSecTrustResultInvalid; + BOOL shouldAllow; + OSStatus trustError; + + @synchronized([GULNetworkURLSession class]) { + trustError = SecTrustEvaluate(serverTrust, &trustEval); + } + + if (trustError != errSecSuccess) { + [self->_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession008 + message:@"Cannot evaluate server trust. Error, host" + contexts:@[ @(trustError), self->_request.URL ]]; + shouldAllow = NO; + } else { + // Having a trust level "unspecified" by the user is the usual result, described at + // https://developer.apple.com/library/mac/qa/qa1360 + shouldAllow = + (trustEval == kSecTrustResultUnspecified || trustEval == kSecTrustResultProceed); + } + + // Call the call back with the permission. + callback(shouldAllow); + + CFRelease(serverTrust); + }); + return; + } + + // Default handling for other Auth Challenges. + completionHandler(NSURLSessionAuthChallengePerformDefaultHandling, nil); +} + +#pragma mark - Internal Methods + +/// Stores system completion handler with session ID as key. +- (void)addSystemCompletionHandler:(GULNetworkSystemCompletionHandler)handler + forSession:(NSString *)identifier { + if (!handler) { + [_loggerDelegate + GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession009 + message:@"Cannot store nil system completion handler in network"]; + return; + } + + if (!identifier.length) { + [_loggerDelegate + GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession010 + message: + @"Cannot store system completion handler with empty network " + "session identifier"]; + return; + } + + GULMutableDictionary *systemCompletionHandlers = + [[self class] sessionIDToSystemCompletionHandlerDictionary]; + if (systemCompletionHandlers[identifier]) { + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelWarning + messageCode:kGULNetworkMessageCodeURLSession011 + message:@"Got multiple system handlers for a single session ID" + context:identifier]; + } + + systemCompletionHandlers[identifier] = handler; +} + +/// Calls the system provided completion handler with the session ID stored in the dictionary. +/// The handler will be removed from the dictionary after being called. +- (void)callSystemCompletionHandler:(NSString *)identifier { + GULMutableDictionary *systemCompletionHandlers = + [[self class] sessionIDToSystemCompletionHandlerDictionary]; + GULNetworkSystemCompletionHandler handler = [systemCompletionHandlers objectForKey:identifier]; + + if (handler) { + [systemCompletionHandlers removeObjectForKey:identifier]; + + dispatch_async(dispatch_get_main_queue(), ^{ + handler(); + }); + } +} + +/// Sets or updates the session ID of this session. +- (void)setSessionID:(NSString *)sessionID { + _sessionID = [sessionID copy]; +} + +/// Creates a background session configuration with the session ID using the supported method. +- (NSURLSessionConfiguration *)backgroundSessionConfigWithSessionID:(NSString *)sessionID { +#if (TARGET_OS_OSX && defined(MAC_OS_X_VERSION_10_10) && \ + MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_10) || \ + TARGET_OS_TV || \ + (TARGET_OS_IOS && defined(__IPHONE_8_0) && __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_8_0) + + // iOS 8/10.10 builds require the new backgroundSessionConfiguration method name. + return [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:sessionID]; + +#elif (TARGET_OS_OSX && defined(MAC_OS_X_VERSION_10_10) && \ + MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_10) || \ + (TARGET_OS_IOS && defined(__IPHONE_8_0) && __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_8_0) + + // Do a runtime check to avoid a deprecation warning about using + // +backgroundSessionConfiguration: on iOS 8. + if ([NSURLSessionConfiguration + respondsToSelector:@selector(backgroundSessionConfigurationWithIdentifier:)]) { + // Running on iOS 8+/OS X 10.10+. + return [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:sessionID]; + } else { + // Running on iOS 7/OS X 10.9. + return [NSURLSessionConfiguration backgroundSessionConfiguration:sessionID]; + } + +#else + // Building with an SDK earlier than iOS 8/OS X 10.10. + return [NSURLSessionConfiguration backgroundSessionConfiguration:sessionID]; +#endif +} + +- (void)maybeRemoveTempFilesAtURL:(NSURL *)folderURL expiringTime:(NSTimeInterval)staleTime { + if (!folderURL.absoluteString.length) { + return; + } + + NSFileManager *fileManager = [NSFileManager defaultManager]; + NSError *error = nil; + + NSArray *properties = @[ NSURLCreationDateKey ]; + NSArray *directoryContent = + [fileManager contentsOfDirectoryAtURL:folderURL + includingPropertiesForKeys:properties + options:NSDirectoryEnumerationSkipsSubdirectoryDescendants + error:&error]; + if (error && error.code != NSFileReadNoSuchFileError) { + [_loggerDelegate + GULNetwork_logWithLevel:kGULNetworkLogLevelDebug + messageCode:kGULNetworkMessageCodeURLSession012 + message:@"Cannot get files from the temporary network folder. Error" + context:error]; + return; + } + + if (!directoryContent.count) { + return; + } + + NSTimeInterval now = [NSDate date].timeIntervalSince1970; + for (NSURL *tempFile in directoryContent) { + NSDate *creationDate; + BOOL getCreationDate = + [tempFile getResourceValue:&creationDate forKey:NSURLCreationDateKey error:NULL]; + if (!getCreationDate) { + continue; + } + NSTimeInterval creationTimeInterval = creationDate.timeIntervalSince1970; + if (fabs(now - creationTimeInterval) > staleTime) { + [self removeTempItemAtURL:tempFile]; + } + } +} + +/// Removes the temporary file written to disk for sending the request. It has to be cleaned up +/// after the session is done. +- (void)removeTempItemAtURL:(NSURL *)fileURL { + if (!fileURL.absoluteString.length) { + return; + } + + NSFileManager *fileManager = [NSFileManager defaultManager]; + NSError *error = nil; + + if (![fileManager removeItemAtURL:fileURL error:&error] && error.code != NSFileNoSuchFileError) { + [_loggerDelegate + GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession013 + message:@"Failed to remove temporary uploading data file. Error" + context:error.localizedDescription]; + } +} + +/// Gets the fetcher with the session ID. ++ (instancetype)fetcherWithSessionIdentifier:(NSString *)sessionIdentifier { + NSMapTable *sessionIdentifierToFetcherMap = [self sessionIDToFetcherMap]; + GULNetworkURLSession *session = [sessionIdentifierToFetcherMap objectForKey:sessionIdentifier]; + if (!session && [sessionIdentifier hasPrefix:kGULNetworkBackgroundSessionConfigIDPrefix]) { + session = [[GULNetworkURLSession alloc] initWithNetworkLoggerDelegate:nil]; + [session setSessionID:sessionIdentifier]; + [sessionIdentifierToFetcherMap setObject:session forKey:sessionIdentifier]; + } + return session; +} + +/// Returns a map of the fetcher by session ID. Creates a map if it is not created. ++ (NSMapTable *)sessionIDToFetcherMap { + static NSMapTable *sessionIDToFetcherMap; + + static dispatch_once_t sessionMapOnceToken; + dispatch_once(&sessionMapOnceToken, ^{ + sessionIDToFetcherMap = [NSMapTable strongToWeakObjectsMapTable]; + }); + return sessionIDToFetcherMap; +} + +/// Returns a map of system provided completion handler by session ID. Creates a map if it is not +/// created. ++ (GULMutableDictionary *)sessionIDToSystemCompletionHandlerDictionary { + static GULMutableDictionary *systemCompletionHandlers; + + static dispatch_once_t systemCompletionHandlerOnceToken; + dispatch_once(&systemCompletionHandlerOnceToken, ^{ + systemCompletionHandlers = [[GULMutableDictionary alloc] init]; + }); + return systemCompletionHandlers; +} + +- (NSURL *)temporaryFilePathWithSessionID:(NSString *)sessionID { + NSString *tempName = [NSString stringWithFormat:@"GULUpload_temp_%@", sessionID]; + return [_networkDirectoryURL URLByAppendingPathComponent:tempName]; +} + +/// Makes sure that the directory to store temp files exists. If not, tries to create it and returns +/// YES. If there is anything wrong, returns NO. +- (BOOL)ensureTemporaryDirectoryExists { + NSFileManager *fileManager = [NSFileManager defaultManager]; + NSError *error = nil; + + // Create a temporary directory if it does not exist or was deleted. + if ([_networkDirectoryURL checkResourceIsReachableAndReturnError:&error]) { + return YES; + } + + if (error && error.code != NSFileReadNoSuchFileError) { + [_loggerDelegate + GULNetwork_logWithLevel:kGULNetworkLogLevelWarning + messageCode:kGULNetworkMessageCodeURLSession014 + message:@"Error while trying to access Network temp folder. Error" + context:error]; + } + + NSError *writeError = nil; + + [fileManager createDirectoryAtURL:_networkDirectoryURL + withIntermediateDirectories:YES + attributes:nil + error:&writeError]; + if (writeError) { + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession015 + message:@"Cannot create temporary directory. Error" + context:writeError]; + return NO; + } + + // Set the iCloud exclusion attribute on the Documents URL. + [self excludeFromBackupForURL:_networkDirectoryURL]; + + return YES; +} + +- (void)excludeFromBackupForURL:(NSURL *)url { + if (!url.path) { + return; + } + + // Set the iCloud exclusion attribute on the Documents URL. + NSError *preventBackupError = nil; + [url setResourceValue:@YES forKey:NSURLIsExcludedFromBackupKey error:&preventBackupError]; + if (preventBackupError) { + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession016 + message:@"Cannot exclude temporary folder from iTunes backup"]; + } +} + +- (void)URLSession:(NSURLSession *)session + task:(NSURLSessionTask *)task + willPerformHTTPRedirection:(NSHTTPURLResponse *)response + newRequest:(NSURLRequest *)request + completionHandler:(void (^)(NSURLRequest *))completionHandler { + NSArray *nonAllowedRedirectionCodes = @[ + @(kGULNetworkHTTPStatusCodeFound), @(kGULNetworkHTTPStatusCodeMovedPermanently), + @(kGULNetworkHTTPStatusCodeMovedTemporarily), @(kGULNetworkHTTPStatusCodeMultipleChoices) + ]; + + // Allow those not in the non allowed list to be followed. + if (![nonAllowedRedirectionCodes containsObject:@(response.statusCode)]) { + completionHandler(request); + return; + } + + // Do not allow redirection if the response code is in the non-allowed list. + NSURLRequest *newRequest = request; + + if (response) { + newRequest = nil; + } + + completionHandler(newRequest); +} + +#pragma mark - Helper Methods + +- (void)callCompletionHandler:(GULNetworkURLSessionCompletionHandler)handler + withResponse:(NSHTTPURLResponse *)response + data:(NSData *)data + error:(NSError *)error { + if (error) { + [_loggerDelegate GULNetwork_logWithLevel:kGULNetworkLogLevelError + messageCode:kGULNetworkMessageCodeURLSession017 + message:@"Encounter network error. Code, error" + contexts:@[ @(error.code), error ]]; + } + + if (handler) { + dispatch_async(dispatch_get_main_queue(), ^{ + handler(response, data, self->_sessionID, error); + }); + } +} + +- (void)populateSessionConfig:(NSURLSessionConfiguration *)sessionConfig + withRequest:(NSURLRequest *)request { + sessionConfig.HTTPAdditionalHeaders = request.allHTTPHeaderFields; + sessionConfig.timeoutIntervalForRequest = request.timeoutInterval; + sessionConfig.timeoutIntervalForResource = request.timeoutInterval; + sessionConfig.requestCachePolicy = request.cachePolicy; +} + +@end |