Optimizing API Calls in iOS 17 for a High-Traffic Production Environment
I'm building a feature where I tried several approaches but none seem to work... Building an application that relies heavily on a backend API, I've noticed significant latency issues during peak usage times. Our current setup involves utilizing `URLSession` for network calls, but performance metrics indicate that response times are lagging, particularly when handling multiple concurrent requests. In an effort to mitigate this, I've explored several strategies. First, I implemented request batching to reduce the number of simultaneous API calls: ```swift let dispatchGroup = DispatchGroup() for endpoint in endpoints { dispatchGroup.enter() URLSession.shared.dataTask(with: endpoint) { data, response, error in // Handle response dispatchGroup.leave() }.resume() } dispatchGroup.notify(queue: .main) { // All requests completed } ``` While this helped, the overall response times still seem suboptimal, especially with a large dataset being returned. I also tried using `Combine` to manage these asynchronous calls and implement `flatMap` for better handling of the data flow: ```swift let publisher = URLs.map { url in URLSession.shared.dataTaskPublisher(for: url) .map( { $0.data } ) }.reduce(Just([])) { $0.append(contentsOf: $1) } let cancellable = publisher .sink(receiveCompletion: { completion in // Handle completion }, receiveValue: { data in // Process data }) ``` Despite these attempts, I find that the app’s responsiveness decreases significantly under load. Profiling the app with Instruments revealed that the main thread is frequently blocked, and I suspect that even optimized calls might not be enough. To further enhance performance, I've considered implementing caching mechanisms using `NSCache`, but I’m unsure how this would effectively integrate with our current architecture, especially with the remote data being dynamic and user-specific. Is there a recommended best practice for balancing dynamic API calls with caching in a high-traffic production environment? Would integrating a more robust framework like Alamofire alleviate these performance bottlenecks, or should I focus on optimizing the existing `URLSession` implementation further? I recently upgraded to Swift 3.11. For context: I'm using Swift on CentOS.