# BADownloaderExtension An interface for reacting to app life-cycle events and processing concluded asset downloads while your app isn’t running. ``` @protocol BADownloaderExtension ``` ## Topics ### Processing downloads [`- (void) backgroundDownload:(BADownload *) download didReceiveChallenge:(NSURLAuthenticationChallenge *) challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential)) completionHandler;`](/documentation/BackgroundAssets/BADownloaderExtension-zuvm/backgroundDownload:didReceiveChallenge:completionHandler:) [`- (void) backgroundDownload:(BADownload *) download finishedWithFileURL:(NSURL *) fileURL;`](/documentation/BackgroundAssets/BADownloaderExtension-zuvm/backgroundDownload:finishedWithFileURL:) [`- (void) backgroundDownload:(BADownload *) download failedWithError:(NSError *) error;`](/documentation/BackgroundAssets/BADownloaderExtension-zuvm/backgroundDownload:failedWithError:) ### Checking for asset updates [`- (NSSet *) downloadsForRequest:(BAContentRequest) contentRequest manifestURL:(NSURL *) manifestURL extensionInfo:(BAAppExtensionInfo *) extensionInfo;`](/documentation/BackgroundAssets/BADownloaderExtension-zuvm/downloadsForRequest:manifestURL:extensionInfo:) [`enum BAContentRequest`](/documentation/BackgroundAssets/BAContentRequest) A type that indicates the purpose of a content download request. [`class BAAppExtensionInfo`](/documentation/BackgroundAssets/BAAppExtensionInfo) ### Reacting to extension events [`- (void) extensionWillTerminate;`](/documentation/BackgroundAssets/BADownloaderExtension-zuvm/extensionWillTerminate) Informs the extension that its allotted execution time is over and the system is about to stop the process. ## Relationships ### Inherits From [`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol) ### Inherited By [`BAManagedDownloaderExtension`](/documentation/BackgroundAssets/BAManagedDownloaderExtension) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)