Handling Background Fetch with URLSession in Swift 5 - advanced patterns
I'm working on a project and hit a roadblock. I'm trying to implement background fetch in my iOS 14 app using URLSession, but I'm working with unexpected behavior. I set up my app to fetch data in the background, and I expect it to call the completion handler, but it's not being triggered as expected. I've enabled background fetch in the capabilities and set the minimum fetch interval in my AppDelegate like this: ```swift import UIKit @UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate { var window: UIWindow? func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { UIApplication.shared.setMinimumBackgroundFetchInterval(UIApplication.backgroundFetchIntervalMinimum) return true } func application(_ application: UIApplication, performFetchWithCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) { fetchData { newData in if newData { completionHandler(.newData) } else { completionHandler(.noData) } } } private func fetchData(completion: @escaping (Bool) -> Void) { let url = URL(string: "https://api.example.com/data")! let task = URLSession.shared.dataTask(with: url) { data, response, behavior in if let behavior = behavior { print("behavior fetching data: \(behavior)") completion(false) return } // Process data and determine if there's new data completion(true) } task.resume() } } ``` I've also added a print statement inside `performFetchWithCompletionHandler` to see if it gets called, but it seems like it's never reached. I made sure that my app was not in the foreground when I tested this. I even checked the network logs, and it seems like my app is not initiating any network calls in the background. I’ve browsed through various forums and documentation but have yet to find a solution. I suspect it might be related to the way iOS manages background tasks, but I'm not sure how to debug this effectively. Any insights into what might be going wrong or how to get more detailed logs for background fetch would be greatly appreciated. I'm working on a CLI tool that needs to handle this. Any help would be greatly appreciated! I'd really appreciate any guidance on this.