General: Forums subtopic: App & System Services > Networking TN3151 Choosing the right networking API Networking Overview document — Despite the fact that this is in the archive, this is still really useful. TLS for App Developers forums post Choosing a Network Debugging Tool documentation WWDC 2019 Session 712 Advances in Networking, Part 1 — This explains the concept of constrained networking, which is Apple’s preferred solution to questions like How do I check whether I’m on Wi-Fi? TN3135 Low-level networking on watchOS TN3179 Understanding local network privacy Adapt to changing network conditions tech talk Understanding Also-Ran Connections forums post Extra-ordinary Networking forums post Foundation networking: Forums tags: Foundation, CFNetwork URL Loading System documentation — NSURLSession, or URLSession in Swift, is the recommended API for HTTP[S] on Apple platforms. Moving to Fewer, Larger Transfers forums post Testing Background Session Code forums post Network framework: Forums tag: Network Network framework documentation — Network framework is the recommended API for TCP, UDP, and QUIC on Apple platforms. Building a custom peer-to-peer protocol sample code (aka TicTacToe) Implementing netcat with Network Framework sample code (aka nwcat) Configuring a Wi-Fi accessory to join a network sample code Moving from Multipeer Connectivity to Network Framework forums post NWEndpoint History and Advice forums post Wi-Fi (general): How to modernize your captive network developer news post Wi-Fi Fundamentals forums post Filing a Wi-Fi Bug Report forums post Working with a Wi-Fi Accessory forums post — This is part of the Extra-ordinary Networking series. Wi-Fi (iOS): TN3111 iOS Wi-Fi API overview technote Wi-Fi Aware framework documentation WirelessInsights framework documentation iOS Network Signal Strength forums post Network Extension Resources Wi-Fi on macOS: Forums tag: Core WLAN Core WLAN framework documentation Secure networking: Forums tags: Security Apple Platform Security support document Preventing Insecure Network Connections documentation — This is all about App Transport Security (ATS). WWDC 2017 Session 701 Your Apps and Evolving Network Security Standards [1] — This is generally interesting, but the section starting at 17:40 is, AFAIK, the best information from Apple about how certificate revocation works on modern systems. Available trusted root certificates for Apple operating systems support article Requirements for trusted certificates in iOS 13 and macOS 10.15 support article About upcoming limits on trusted certificates support article Apple’s Certificate Transparency policy support article What’s new for enterprise in iOS 18 support article — This discusses new key usage requirements. Technote 2232 HTTPS Server Trust Evaluation Technote 2326 Creating Certificates for TLS Testing QA1948 HTTPS and Test Servers Miscellaneous: More network-related forums tags: 5G, QUIC, Bonjour On FTP forums post Using the Multicast Networking Additional Capability forums post Investigating Network Latency Problems forums post Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" [1] This video is no longer available from Apple, but the URL should help you locate other sources of this info.

I'm working on an API client for a REST service that uses a custom token-based authentiation scheme. The app hits a specificed authentication endpoint with a username and password, said endpoint returns a token that's good for X amount of time, and the app passes that token along with every subsequent request. When that token expires, we start over.Most literature out there tells me to manually set the Authorization header on my request, but official Apple documentation discourages this, as that header is meant to be 'owned' by the built-in HTTP loading system. That said, official documentation on the 'correct' way to do this is shockingly lacking, and the standard didReceiveChallenge callbacks seem better suited for non-custom Basic/Digest/etc authentication schemes. One thought I had was registering my own URLProtocol subclass to handle our custom flow. However, while I haven't had a chance to sit down and take a crack at that yet, my understanding from skimming these forums is that it's suffering from some bit-rot right now, so it 'might' (?) not be the best choice. That, and it's also not clear to me whether the rules around the Authorization header change when a custom URLProtocol is in play.So, community (paging eskimo in particular!), what's the correct way for me to go about this?

IMPORTANT Rather than use the code below, I recommend that you adopt Swift’s shiny-new Subprocess package. That’s what I’m doing! (-: Running a child process using Process (or NSTask in Objective-C) is easy, but piping data to and from the child’s stdin and stdout is surprisingly tricky. I regularly see folks confused by this. Moreover, it’s easy to come up with a solution that works most of the time, but suffers from weird problems that only show up in the field [1]. I recently had a couple of DTS incidents from folks struggling with this, so I sat down and worked through the details. Pasted below is the results of that effort, namely, a single function that will start a child process, pass it some data on stdin, read the data from the child’s stdout, and call a completion handler when everything is done. There are some things to note here, some obvious, some not so much: I’ve included Swift and Objective-C versions of the code. Both versions work the same way. The Swift version has all the comments. If you decide to base your code on the Objective-C version, copy the comments from there. I didn’t bother collecting stderr. That’s not necessary in many cases and, if you need it, it’s not hard to extend the code to handle that case. I use Dispatch I/O rather than FileHandle to manage the I/O channels. Dispatch I/O is well suited to this task. In contrast, FileHandle has numerous problems working with pipes. For the details, see Whither FileHandle?. This single function is way longer than I’d normally tolerate. This is partly due to the extensive comments and party due to my desire to maintain focus. When wrapping Process it’s very easy to run afoul of architecture astronaut-ism. Indeed, I have a much more full-featured Process wrapper sitting on my hard disk, but that’s going to stay there in favour of this approach (-: Handling a child process correctly involves some gnarly race conditions. The code has extensive comments explaining how I deal with those. If you have any questions or comments about this, put them in a new thread. Make sure to tag that thread with Foundation and Inter-process communication so that I see it. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" [1] Indeed, this post shows that I’ve made this sort of mistake myself )-:

When the UITextField is touched, it crashes on "[UITextField becomeFirstResponder]" iOS 15.3.1 keyboard: Chinese keyboard of system

I'm struggling to understand why the async-await version of URLSession download task APIs do not call the delegate functions, whereas the old non-async version that returns a reference to the download task works just fine. Here is my sample code: class DownloadDelegate: NSObject, URLSessionDownloadDelegate { func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) { // This only prints the percentage of the download progress. let calculatedProgress = Float(totalBytesWritten) / Float(totalBytesExpectedToWrite) let formatter = NumberFormatter() formatter.numberStyle = .percent print(formatter.string(from: NSNumber(value: calculatedProgress))!) } } // Here's the VC. final class DownloadsViewController: UIViewController { private let url = URL(string: "https://pixabay.com/get/g0b9fa2936ff6a5078ea607398665e8151fc0c10df7db5c093e543314b883755ecd43eda2b7b5178a7e613a35541be6486885fb4a55d0777ba949aedccc807d8c_1280.jpg")! private let delegate = DownloadDelegate() private lazy var session = URLSession(configuration: .default, delegate: delegate, delegateQueue: nil) // for the async-await version private var task: Task<Void, Never>? // for the old version private var downloadTask: URLSessionDownloadTask? override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) task?.cancel() task = nil task = Task { let (_, _) = try! await session.download(for: URLRequest(url: url)) self.task = nil } // If I uncomment this, the progress listener delegate function above is called. // downloadTask?.cancel() // downloadTask = nil // downloadTask = session.downloadTask(with: URLRequest(url: url)) // downloadTask?.resume() } } What am I missing here?

Greetings, I would like to understand this URLCache behavior for two different requests to the same end point but with a different header value. Here is a code with comment explaining the behavior. // Create a request to for a url. let url = URL(string: "https://<my url>?f=json")! var request = URLRequest(url: url) // Set custom header with a value. request.setValue("myvalue", forHTTPHeaderField: "CustomField") // Send request to get the response. let (data, response) = try await URLSession.shared.data(for: request) print("data: \(String(describing: String(data: data, encoding: .utf8)))") print("response: \(response)") // Create second request to the same url but with different value of custom header field. var request2 = URLRequest(url: url) request2.setValue("newvalue", forHTTPHeaderField: "CustomField") // Check the URL cache for second request and it returns the response // of the first request even though the second request has different header value. let cachedResponse = URLCache.shared.cachedResponse(for: request2) print("cachedResponse: \(cachedResponse?.response)") Is this a bug in URLCache that request headers are not matched while returning the response? Is this an expected behavior? If yes, why?

Hey, I am just about to prepare my app for Swift 6, and facing the issue that UserDefaults is not Sendable. The documentation states that its thread safe, so I am wondering, why is it not marked as Sendable? Was it just forgotten? Is it safe to mark it as nonisolated(unsafe) or @unchecked Sendable?

I'm a font developer. In the development process, I will revise a font and overwrite the OTF file that is currently enabled (registered) with macOS. If I then launch an app, it will immediately use the revised version of the font; while apps that are already loaded will continue to use the old version. This suggests that each app is loading new and separate font data, rather than getting it from some existing cache in memory. Yet macOS does have a "font cache" of some sort. Some apps, like TextEdit, seem to only load the fonts that they need to use. However, other apps, like Pages, load every enabled (registered) font on the OS!! (According to the Open Files list in Activity Monitor.) Given that /System/Library/Fonts/ is 625 Mb, and we can't disable any of it, isn't that a lot of data to be repeating? How many fonts is too many fonts? I can't find much documentation about the process.

We are getting a crash _dispatch_assert_queue_fail when the cancellationHandler on NSProgress is called. We do not see this with iOS 17.x, only on iOS 18. We are building in Swift 6 language mode and do not have any compiler warnings. We have a type whose init looks something like this: init( request: URLRequest, destinationURL: URL, session: URLSession ) { progress = Progress() progress.kind = .file progress.fileOperationKind = .downloading progress.fileURL = destinationURL progress.pausingHandler = { [weak self] in self?.setIsPaused(true) } progress.resumingHandler = { [weak self] in self?.setIsPaused(false) } progress.cancellationHandler = { [weak self] in self?.cancel() } When the progress is cancelled, and the cancellation handler is invoked. We get the crash. The crash is not reproducible 100% of the time, but it happens significantly often. Especially after cleaning and rebuilding and running our tests. * thread #4, queue = 'com.apple.root.default-qos', stop reason = EXC_BREAKPOINT (code=1, subcode=0x18017b0e8) * frame #0: 0x000000018017b0e8 libdispatch.dylib`_dispatch_assert_queue_fail + 116 frame #1: 0x000000018017b074 libdispatch.dylib`dispatch_assert_queue + 188 frame #2: 0x00000002444c63e0 libswift_Concurrency.dylib`swift_task_isCurrentExecutorImpl(swift::SerialExecutorRef) + 284 frame #3: 0x000000010b80bd84 MyTests`closure #3 in MyController.init() at MyController.swift:0 frame #4: 0x000000010b80bb04 MyTests`thunk for @escaping @callee_guaranteed @Sendable () -> () at <compiler-generated>:0 frame #5: 0x00000001810276b0 Foundation`__20-[NSProgress cancel]_block_invoke_3 + 28 frame #6: 0x00000001801774ec libdispatch.dylib`_dispatch_call_block_and_release + 24 frame #7: 0x0000000180178de0 libdispatch.dylib`_dispatch_client_callout + 16 frame #8: 0x000000018018b7dc libdispatch.dylib`_dispatch_root_queue_drain + 1072 frame #9: 0x000000018018bf60 libdispatch.dylib`_dispatch_worker_thread2 + 232 frame #10: 0x00000001012a77d8 libsystem_pthread.dylib`_pthread_wqthread + 224 Any thoughts on why this is crashing and what we can do to work-around it? I have not been able to extract our code into a simple reproducible case yet. And I mostly see it when running our code in a testing environment (XCTest). Although I have been able to reproduce it running an app a few times, it's just less common.

All the threads only contain system calls. The crashed thread only contains a single call to my app's code which is main.swift:13. What could cause such a crash? crash.crash

Hi there, I uploaded an update bundle for the posted app, but I got a rejection message. ITMS-90048: This bundle is invalid - Your archive contains paths that are not allowed: [._Symbols] The XCode version I'm using is 16.2, and I've been trying to find a route using Run Script and Finder, but I don't know what the hell it is about. Does anybody know what could cause this issue? Any help would be appreciated. Thanks.

Hey there! I faced issue in iOS 18 and newer when Spotlight search doesn't show my App in results. In older versions it works. Here is my code: func configureUserActivitity(with id: String, keywords: [String]) { let activity = NSUserActivity(activityType: id) activity.contentAttributeSet = self.defaultAttributeSet activity.isEligibleForSearch = true activity.keywords = Set(keywords) activity.becomeCurrent() self.userActivity = activity } I didn't find any reasons why it doesn't work now. Maybe I should report a bug?

My app started crashing since iOS 18.4 update. Crashes started happening in 18.4 beta and are still happening in the official 18.4 RTM build (22E240). Crash is happening randomly and I cannot reproduce it, but it affects a few percent of users. As you can see in log, crash happen when NSAttributedString is loading HTML with init(data:options:documentAttributes:) with .html documentType. Crash-2025-04-02-154720.ips

The current live version of my app is 1.1.0, and I intended to create a new submission version, 1.1.1. However, I accidentally entered it as 1.0.8. In App Store Connect, I couldn't find any button to delete or modify the 1.0.8 version, nor could I add another submission version. As a result, I tried to upload the build for version 1.0.8 via Xcode, but an even worse issue occurred—Xcode displayed an error: "A version 1.1.0 already exists, which is higher than 1.0.8, so the upload path is closed." I can't update my app now or later, what should I do to fix it?

Let’s try calculating one day after "2023/11/04 12:00 New York time". let timeZone = TimeZone(identifier: "America/New_York")! var calendar = Calendar(identifier: .gregorian) calendar.timeZone = timeZone var dateFormatter = DateFormatter() dateFormatter.timeZone = timeZone dateFormatter.locale = .init(identifier: "ja_JP") dateFormatter.dateStyle = .short dateFormatter.timeStyle = .short var dateComponents = DateComponents() dateComponents.year = 2023 dateComponents.month = 11 dateComponents.day = 4 dateComponents.hour = 12 // At New York 2023/11/04 12:00 let date1 = calendar.date(from: dateComponents)! print(dateFormatter.string(from: date1)) // Add 1 day let date2 = calendar.date(byAdding: .day, value: 1, to: date1)! print(dateFormatter.string(from: date2))``` The output is: 2023/11/04 12:00 2023/11/05 12:00 Now, let’s try the following—also to get the time one day later: let date2 = calendar.date(byAdding: .minute, value: 24 * 60, to: date1)! print(dateFormatter.string(from: date2)) This outputs: 2023/11/04 12:00 2023/11/05 11:00 What's Causing This Difference? It’s likely due to Daylight Saving Time (DST). But why do we get different results between the first and second examples?

Hi, I work at OneSignal, a third-party SDK, and have the following two crash reports submitted by a client for the same issue. Because the crash originates from our SDK, even if the root cause may be elsewhere, the onus is on our team to try to resolve this crash. Additionally, my information is limited as this is not our own crash report. I'm trying to figure out why this crash happens and how we can address it within our SDK. Crash Reported: Fatal Exception: NSInvalidArgumentException [NSMutableDictionary __addObject:forKey:]: object cannot be nil Context: Our SDK makes a call to [NSUserDefaults(NSUserDefaults) objectForKey:] on the standardUserDefaults and passes in a non-null key. It appears further up the call stack, a null value is being added to a dictionary. I assume this is the innards of how the search list is generated. Additional Information: The client states that it seems to happen only once per user and the scale is not extremely high but it is increasing. They are unsure what happened and when. They don't have much information about the devices except it has happened on iOS 18. Log 1: 0 CoreFoundation 0x2d5fc __exceptionPreprocess 1 libobjc.A.dylib 0x31244 objc_exception_throw 2 CoreFoundation 0x15548 -[NSMutableDictionary __addObject:forKey:] 3 CoreFoundation 0x20850 -[__NSDictionaryM __apply:context:] 4 CoreFoundation 0x54700 ___CFPrefsDeliverPendingKVONotificationsGuts_block_invoke 5 CoreFoundation 0x52988 __CFDictionaryApplyFunction_block_invoke 6 CoreFoundation 0x52524 CFBasicHashApply 7 CoreFoundation 0x21040 CFDictionaryApplyFunction 8 CoreFoundation 0x7a6b0 _CFPrefsDeliverPendingKVONotificationsGuts 9 CoreFoundation 0x777d0 -[_CFXPreferences _deliverPendingKVONotifications] 10 CoreFoundation 0x776ac __108-[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:]_block_invoke 11 CoreFoundation 0x5cf24 normalizeQuintuplet 12 CoreFoundation 0x5cd60 -[_CFXPreferences withSearchListForIdentifier:container:cloudConfigurationURL:perform:] 13 CoreFoundation 0x5cc60 -[_CFXPreferences copyAppValueForKey:identifier:container:configurationURL:] 14 CoreFoundation 0x5c8bc _CFPreferencesCopyAppValueWithContainerAndConfiguration 15 Foundation 0xf0dcc -[NSUserDefaults(NSUserDefaults) objectForKey:] 16 OneSignalCore 0xc7c8 -[OneSignalUserDefaults keyExists:] + 61 (OneSignalUserDefaults.m:61) 17 OneSignalCore 0xc8b0 -[OneSignalUserDefaults getSavedBoolForKey:defaultValue:] + 70 (OneSignalUserDefaults.m:70) 18 OneSignalCore 0xbb10 +[OSPrivacyConsentController requiresUserPrivacyConsent] + 59 (OSPrivacyConsentController.m:59) 19 OneSignalCore 0xbc30 +[OSPrivacyConsentController shouldLogMissingPrivacyConsentErrorWithMethodName:] + 75 (OSPrivacyConsentController.m:75) 20 OneSignalCore 0x4418 +[OneSignalConfigManager shouldAwaitAppIdAndLogMissingPrivacyConsentForMethod:] + 50 (OneSignalConfigManager.m:50) 21 OneSignalOSCore 0x537c OSOperationRepo.flushDeltaQueue(inBackground:) + 140 (OSOperationRepo.swift:140) 22 OneSignalOSCore 0x4868 closure #1 in OSOperationRepo.pollFlushQueue() + 84 (OSOperationRepo.swift:84) 23 OneSignalOSCore 0x5078 thunk for @escaping @callee_guaranteed @Sendable () -> () 24 libdispatch.dylib 0x3fa8 _dispatch_client_callout 25 libdispatch.dylib 0x745c _dispatch_continuation_pop 26 libdispatch.dylib 0x1b620 _dispatch_source_latch_and_call 27 libdispatch.dylib 0x1a1e8 _dispatch_source_invoke 28 libdispatch.dylib 0xb42c _dispatch_lane_serial_drain 29 libdispatch.dylib 0xc124 _dispatch_lane_invoke 30 libdispatch.dylib 0x1738c _dispatch_root_queue_drain_deferred_wlh 31 libdispatch.dylib 0x16bd8 _dispatch_workloop_worker_thread 32 libsystem_pthread.dylib 0x3680 _pthread_wqthread 33 libsystem_pthread.dylib 0x1474 start_wqthread Log 2: Fatal Exception: NSInvalidArgumentException 0 CoreFoundation 0x2d5fc __exceptionPreprocess 1 libobjc.A.dylib 0x31244 objc_exception_throw 2 CoreFoundation 0x15548 -[NSMutableDictionary __addObject:forKey:] 3 CoreFoundation 0x168f0 __72-[CFPrefsSource mergeIntoDictionary:sourceDictionary:cloudKeyEvaluator:]_block_invoke 4 CoreFoundation 0x23ecc -[__NSFrozenDictionaryM __apply:context:] 5 CoreFoundation 0x4f82c -[CFPrefsSource mergeIntoDictionary:sourceDictionary:cloudKeyEvaluator:] 6 CoreFoundation 0x783b8 -[CFPrefsSearchListSource alreadylocked_getDictionary:] 7 CoreFoundation 0x77dfc -[CFPrefsSearchListSource alreadylocked_copyValueForKey:] 8 CoreFoundation 0x77d30 -[CFPrefsSource copyValueForKey:] 9 CoreFoundation 0x77ce4 __76-[_CFXPreferences copyAppValueForKey:identifier:container:configurationURL:]_block_invoke 10 CoreFoundation 0x77690 __108-[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:]_block_invoke 11 CoreFoundation 0x5cf24 normalizeQuintuplet 12 CoreFoundation 0x5cd60 -[_CFXPreferences withSearchListForIdentifier:container:cloudConfigurationURL:perform:] 13 CoreFoundation 0x5cc60 -[_CFXPreferences copyAppValueForKey:identifier:container:configurationURL:] 14 CoreFoundation 0x5c8bc _CFPreferencesCopyAppValueWithContainerAndConfiguration 15 Foundation 0xf0dcc -[NSUserDefaults(NSUserDefaults) objectForKey:] 16 OneSignalCore 0xc7c8 -[OneSignalUserDefaults keyExists:] + 61 (OneSignalUserDefaults.m:61) 17 OneSignalCore 0xcbd8 -[OneSignalUserDefaults getSavedDoubleForKey:defaultValue:] + 107 (OneSignalUserDefaults.m:107) 18 OneSignalFramework 0x8964 +[OneSignal shouldStartNewSession] + 350 (OneSignal.m:350) 19 OneSignalFramework 0xc968 +[OneSignalTracker applicationBecameActive] + 83 (OneSignalTracker.m:83) 20 OneSignalFramework 0xb894 -[OneSignalLifecycleObserver didBecomeActive] + 84 (OneSignalLifecycleObserver.m:84) ...... 55 UIKitCore 0x3ee674 -[UIApplication _run] 56 UIKitCore 0x14e88 UIApplicationMain 57 UnityFramework 0x399aef0 -[UnityFramework runUIApplicationMainWithArgc:argv:] + 96 (main.mm:96) 58 ClientsApp 0x412c main + 28 (main.mm:28)

We have identified an issue when using NumberFormatter with the locale set to it_IT. Specifically, when formatting numbers with exactly four integer digits, the grouping separator is not applied: for example, the number is displayed as 4000,00 instead of the expected 4.000,00. This behavior occurs only with four-digit integers; for instance, 40.000,00 is formatted correctly. The issue appears to affect only iOS 18.4 and later versions.

I want decoded my base64 string and want to create image from it. NSData *data = [NSData dataWithBytes:bpData.rt_wav.data length:sizeof(bpData.rt_wav.data)]; NSMutableString *baseString = [data base64Encoding]; UIImage *image = [UIImage imageWithData:data];

Hi Dev Forums and Quinn "The Eskimo!", Short version Is there sample NWConnection code available that behaves in a similar way to the higher level URLSession and URLRequest APIs? Long version I have not been able to make this question get past the "sensitive language filter" on the dev forums. I figured it might be 'fool' or 'heck', or the X link, but removing each of those still triggers the sensitive language filter. Please see this gist: https://gist.github.com/lzell/8672c26ecb6ee1bb26d3aa3c7d67dd62 Thank you! Lou Zell

We have an enterprise mac OS X application which uses the UserDefaults to store the onboarding states. The strange part here is that the newly installed mac OS X app is still be able to access the UserDefalus data of removed application. Because of this, the application never becomes as a freshly installed app. Is it any limitation to Enterprise mac OS X apps? Could you please provide us the resolution for this issue.