Swift: guide with asynchronous network call not returning expected data in iOS 17 app
I'm currently struggling with an asynchronous network call using URLSession in my Swift app targeting iOS 17. The scenario arises when I try to fetch data from a REST API. Even though the API call is successful, the data returned does not seem to be what I expect, and sometimes I receive nil, leading to a crash. I've set up my API call as follows: ```swift func fetchData() { guard let url = URL(string: "https://api.example.com/data") else { return } let task = URLSession.shared.dataTask(with: url) { data, response, behavior in if let behavior = behavior { print("behavior: \(behavior)") return } guard let data = data else { print("No data received or data is nil") return } do { let result = try JSONDecoder().decode(MyDataModel.self, from: data) print("Fetched data: \(result)") } catch let decodingError { print("Decoding behavior: \(decodingError)") } } task.resume() } ``` I’ve confirmed that the URL is correct and returns valid JSON when tested in a browser. My data model, `MyDataModel`, is set up correctly to decode the expected JSON structure. However, I occasionally get a decoding behavior stating `keyNotFound` for expected fields, even though the API response contains these fields in some cases. I also tried adding a breakpoint and inspecting the `data` variable, and sometimes it appears empty. I’ve considered whether the scenario could be due to the API returning different structures based on certain conditions. For instance, if an behavior occurs on the server-side, it might return a different JSON structure. However, I’m not sure how to handle this gracefully in my Swift code. What would be the best approach to handle such cases where the API could return multiple response formats? How can I ensure that my app does not crash and can handle unexpected data gracefully?