I have several processes maintaining NSXPConnection to an XPC service. The connections are bi-directional. Each side service and clients) of the connection exports an object, and an XPCInterface. The @protocols are different - to the service, and from the service to clients.
So long as all the "clients" fully implement their "call-back" @protocol, there's no problem. All works fine.
However - If a client does NOT implement a method in the "call back protocol", or completely neglects to export an object, or interface - and the service attempts to call back using the nonexistent method -- the XPC connection invalidates immediately.
So far - expected behaviour.
However, if I want the service to behave to the client a little like a "delegate" style -- and check first whether the client "respondsToSelector" or even - supports an interface BEFORE calling it, then this doesn't work.
When my XPC service tries the following on a client connection:
if (xpcConnection.remoteObjectInterface == nil)
os_log_error(myXPCLog, "client has no remote interface);
the condition is never met - i.e. the "remoteObjectInterface is never nil even when the client does NOT configure its NSXPCConnection with any incoming NSXPCInterface, and does not set an "exportedObject"
Furthermore, the next check:
if ([proxy respondsToSelector:@selector(downloadFiltersForCustomer:withReply:)]) {
}
will not only fail - but will drop the connection. The client side gets the invalidation with the following error:
<NSXPCConnection: 0x600000b20000> connection to service with pid 2477 named com.proofpoint.ecd: received an undecodable message for proxy 1 (no exported object to receive message). Dropping message.
I guess the "undecidable message" is the respondsToSelector - because the code doesn't get to attempt anything else afterwards, the connection drops.
Is there a way to do this check "quietly", or suffering only "interruption", but without losing the connection,
Processes & Concurrency
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When using conformance to ObservableObject and then doing async work in a Task, you will get a warning courtesy of Combine if you then update an @Published or @State var from anywhere but the main thread. However, if you are using @Observable there is no such warning.
Also, Thread.current is unavailable in asynchronous contexts, so says the warning. And I have read that in a sense you simply aren't concerned with what thread an async task is on.
So for me, that begs a question. Is the lack of a warning, which when using Combine is rather important as ignoring it could lead to crashes, a pretty major bug that Apple seemingly should have addressed long ago? Or is it just not an issue to update state from another thread, because Xcode is doing that work for us behind the scenes too, just as it manages what thread the async task is running on when we don't specify?
I see a lot of posts about this from around the initial release of Async/Await talking about using await MainActor.run {} at the point the state variable is updated, usually also complaining about the lack of a warning. But ow years later there is still no warning and I have to wonder if this is actually a non issue. On some ways similar to the fact that many of the early posts I have seen related to @Observable have examples of an @Observable ViewModel instantiated in the view as an @State variable, but in fact this is not needed as that is addressed behind the scenes for all properties of an @Observable type.
At least, that is my understanding now, but I am learning Swift coming from a PowerShell background so I question my understanding a lot.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Concurrency
Swift
SwiftUI
Combine
How to execute code on main app when interacted with a live activity, given that they are already interactable.
is there a way without opening the app?
what are the best ways?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Extensions
WidgetKit
ActivityKit
The following code worked as expected on iOS 26 RC, but it no longer works on the official release of iOS 26.
Is there something I need to change in order to make it work on the official version?
Registration
BGTaskScheduler.shared.register(
forTaskWithIdentifier: taskIdentifier,
using: nil
) { task in
//////////////////////////////////////////////////////////////////////
// This closure is not called on the official release of iOS 26
//////////////////////////////////////////////////////////////////////
let task = task as! BGContinuedProcessingTask
var shouldContinue = true
task.expirationHandler = {
shouldContinue = false
}
task.progress.totalUnitCount = 100
task.progress.completedUnitCount = 0
while shouldContinue {
sleep(1)
task.progress.completedUnitCount += 1
task.updateTitle("\(task.progress.completedUnitCount) / \(task.progress.totalUnitCount)", subtitle: "any subtitle")
if task.progress.completedUnitCount == task.progress.totalUnitCount {
break
}
}
let completed = task.progress.completedUnitCount >= task.progress.totalUnitCount
if completed {
task.updateTitle("Completed", subtitle: "")
}
task.setTaskCompleted(success: completed)
}
Request
let request = BGContinuedProcessingTaskRequest(
identifier: taskIdentifier,
title: "any title",
subtitle: "any subtitle",
)
request.strategy = .queue
try BGTaskScheduler.shared.submit(request)
Sample project code:
https://github.com/HikaruSato/ExampleBackgroundProcess
In macOS 26 I noticed there is a section Menu Bar in System Settings which allows to toggle visibility of status items created with NSStatusItem. I'm assuming this is new, since I never noticed it before.
Currently my app has a menu item that allows toggling its status item, but now I wonder whether it should always create the status item and let the user control its visibility from System Settings. Theoretically, keeping this option inside the app could lead to confusion if the user has previously disabled the status item in System Settings, then perhaps forgot about it, and then tries to enable it inside the app, but apparently nothing happens because System Settings overrides the app setting. Should I remove the option inside the app?
This also makes me think of login items, which can be managed both in System Settings and inside the app via SMAppService. Some users ask why my app doesn't have a launch at login option, and I tell them that System Settings already offers that functionality. Since there is SMAppService I could offer an option inside the app that is kept in sync with System Settings, but I prefer to avoid duplicating functionality, particularly if it's something that is changed once by the user and then rarely (if ever) changed afterwards. But I wonder: why can login items be controlled by an app, and the status item cannot (at least I'm not aware of an API that allows to change the option in System Settings)? If the status item can be overridden in System Settings, why do login items behave differently?
We have an application that sets a code signing requirement on a XPC connection between a File Provider extension and the main application. Only with a specific Developer ID certificate <DEVELOPER_ID_TEAM_IDENTIFIER> that designated requirement is not accepted and the application crashes with EXC_CRASH (SIGABRT) and the stacktrace
Thread 1 Crashed:: Dispatch queue: com.apple.root.default-qos
0 libsystem_kernel.dylib 0x19b556388 __pthread_kill + 8
1 libsystem_pthread.dylib 0x19b58f88c pthread_kill + 296
2 libsystem_c.dylib 0x19b498a3c abort + 124
3 libc++abi.dylib 0x19b545384 abort_message + 132
4 libc++abi.dylib 0x19b533cf4 demangling_terminate_handler() + 344
5 libobjc.A.dylib 0x19b1b8dd4 _objc_terminate() + 156
6 libc++abi.dylib 0x19b544698 std::__terminate(void (*)()) + 16
7 libc++abi.dylib 0x19b547c30 __cxxabiv1::failed_throw(__cxxabiv1::__cxa_exception*) + 88
8 libc++abi.dylib 0x19b547bd8 __cxa_throw + 92
9 libobjc.A.dylib 0x19b1aecf8 objc_exception_throw + 448
10 Foundation 0x19d5c3840 -[NSXPCConnection setCodeSigningRequirement:] + 140
11 libxpcfileprovider.dylib 0x301023048 NSXPCConnection.setCodeSigningRequirementFromTeamIdentifier(_:) + 1796
12 libxpcfileprovider.dylib 0x30101dc94 closure #1 in CallbackFileProviderManager.getFileProviderConnection(_:service:completionHandler:interruptionHandler:exportedObject:) + 1936
13 libxpcfileprovider.dylib 0x30101e110 thunk for @escaping @callee_guaranteed @Sendable (@guaranteed NSXPCConnection?, @guaranteed Error?) -> () + 80
14 Foundation 0x19d46c3a4 __72-[NSFileProviderService getFileProviderConnectionWithCompletionHandler:]_block_invoke_2.687 + 284
15 libdispatch.dylib 0x19b3d7b2c _dispatch_call_block_and_release + 32
16 libdispatch.dylib 0x19b3f185c _dispatch_client_callout + 16
17 libdispatch.dylib 0x19b40e490 + 32
18 libdispatch.dylib 0x19b3e9fa4 _dispatch_root_queue_drain + 736
19 libdispatch.dylib 0x19b3ea5d4 _dispatch_worker_thread2 + 156
20 libsystem_pthread.dylib 0x19b58be28 _pthread_wqthread + 232
21 libsystem_pthread.dylib 0x19b58ab74 start_wqthread + 8
The designated codesign requirement on the XPC connection is set to
anchor apple generic and certificate leaf[subject.OU] = <DEVELOPER_ID_TEAM_IDENTIFIER>"
We have verified the designated code sign requirement to be valid on both the main bundle and the embedded extension using:
codesign --verify -v -R '=anchor apple generic and certificate leaf[subject.OU] = "<DEVELOPER_ID_TEAM_IDENTIFIER>"' *.app
codesign --verify -v -R '=anchor apple generic and certificate leaf[subject.OU] = "<DEVELOPER_ID_TEAM_IDENTIFIER>"' *.app/Contents/PlugIns/*
I have followed this post for creating a Launch Agent that provides an XPC service on macOS using Swift-
post link - https://rderik.com/blog/creating-a-launch-agent-that-provides-an-xpc-service-on-macos/
In the swift code the interface of the XPC service is defined by protocols which makes the code nice and neat. I want to implement the XPC service using C APIs for XPC, and C APIs send and receive messages using dictionaries, which need manual handling with conditional statements.
I want to know if its possible to go with the protocol based approach with C APIs.
Hi!
Could you please point me to the official documentation or recommended approach for launching the host app from a Share Extension?
The scenario is:
The user is sharing some text to my app.
I need launch App and show this text.
At the moment, I'm using the following hack:
let selector = NSSelectorFromString("sharedApplication")
if let app = UIApplication.perform(selector)?.takeUnretainedValue() as? UIApplication,
app.responds(to: #selector(UIApplication.open(_:options:completionHandler:))) {
app.open(url, options: [:], completionHandler: nil)
}
This does work, but it's terrible.
So, the question:
What is the official way to open the host app from within a Share Extension?
Thanks!
In iOS Background Execution limits, I see this:
When the user ‘force quits’ an app by swiping up in the multitasking UI, iOS interprets that to mean that the user doesn’t want the app running at all. iOS also sets a flag that prevents the app from being launched in the background. That flag gets cleared when the user next launches the app manually.
However, I see that when I close an app on iPadOS 26 with the red X, the app doesn't appear in the multitasking UI. So are they treated as force closes and prevented from running background tasks?
I'm trying to schedule a background task that will run on an iPhone and I'm looking into creating a task request using BGProcessingTaskRequest and scheduled it using BGTaskScheduler.shared.submit().
Per earliestBeginDate documentation, this property can be used to specify the earliest time a background task will be launched by OS. All clear here.
However, the question is: how is the value interpreted with respect to timezone ? Is the specified date in device timezone ? Is GMT ? Is something else ?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
iOS
Background Tasks
Foundation
This is the functionality I am trying to achieve with libxpc:
There's one xpc server and two xpc clients. When the xpc server receives a particular dictionary item from clientB, the server needs to send a response to both clientA and clientB.
This is the approach I am currently using:
First, clientA creates a dictionary item that indicates that this item is from clientA. Now, clientA sends this dictionary to server. When server receives this item, it stores the connection instance with clientA in a global variable. Next, when clientB sends a particular dictionary item, server uses this global variable where it perviously stored clientA's connection instance to send a response back to clientA, alongside clientB.
Only one edge case I can see is that when clientA closes this connection instance, server will be trying to send a response to an invalidated connection.
Question:
Is this approach recommended? Any edge cases I should be aware of? Is there any better way to achieve this functionality?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Inter-process communication
XPC
Dear Apple:
We are developing an app for file sharing between mobile devices. We want to create an iOS app that can continue sharing files with other devices even when it is running in the background. We are using WLAN channels for file sharing. Could you please advise on which background persistence measures we should use to ensure the iOS app can maintain file transfer when it goes to the background? Thank you.
Hello everyone!
I'm having a problem with background tasks running in the foreground.
When a user enters the app, a background task is triggered. I've written some code to check if the app is in the foreground and to prevent the task from running, but it doesn't always work. Sometimes the task runs in the background as expected, but other times it runs in the foreground, as I mentioned earlier.
Could it be that I'm doing something wrong? Any suggestions would be appreciated.
here is code:
class BackgroundTaskService {
@Environment(\.scenePhase) var scenePhase
static let shared = BackgroundTaskService()
private init() {}
// MARK: - create task
func createCheckTask() {
let identifier = TaskIdentifier.check
BGTaskScheduler.shared.getPendingTaskRequests { requests in
if requests.contains(where: { $0.identifier == identifier.rawValue }) {
return
}
self.createByInterval(identifier: identifier.rawValue, interval: identifier.interval)
}
}
private func createByInterval(identifier: String, interval: TimeInterval) {
let request = BGProcessingTaskRequest(identifier: identifier)
request.earliestBeginDate = Date(timeIntervalSinceNow: interval)
scheduleTask(request: request)
}
// MARK: submit task
private func scheduleTask(request: BGProcessingTaskRequest) {
do {
try BGTaskScheduler.shared.submit(request)
} catch {
// some actions with error
}
}
// MARK: background actions
func checkTask(task: BGProcessingTask) {
let today = Calendar.current.startOfDay(for: Date())
let lastExecutionDate = UserDefaults.standard.object(forKey: "lastCheckExecutionDate") as? Date ?? Date.distantPast
let notRunnedToday = !Calendar.current.isDate(today, inSameDayAs: lastExecutionDate)
guard notRunnedToday else {
task.setTaskCompleted(success: true)
createCheckTask()
return
}
if scenePhase == .background {
TaskActionStore.shared.getAction(for: task.identifier)?()
}
task.setTaskCompleted(success: true)
UserDefaults.standard.set(today, forKey: "lastCheckExecutionDate")
createCheckTask()
}
}
And in AppDelegate:
BGTaskScheduler.shared.register(forTaskWithIdentifier: "check", using: nil) { task in
guard let task = task as? BGProcessingTask else { return }
BackgroundTaskService.shared.checkNodeTask(task: task)
}
BackgroundTaskService.shared.createCheckTask()
How can I return the results of a Spotlight query synchronously from a Swift function?
I want to return a [String] that contains the items that match the query, one item per array element.
I specifically want to find all data for Spotlight items in the /Applications folder that have a kMDItemAppStoreAdamID (if there is a better predicate than kMDItemAppStoreAdamID > 0, please let me know).
The following should be the correct query:
let query = NSMetadataQuery()
query.predicate = NSPredicate(format: "kMDItemAppStoreAdamID > 0")
query.searchScopes = ["/Applications"]
I would like to do this for code that can run on macOS 10.13+, which precludes using Swift Concurrency. My project already uses the latest PromiseKit, so I assume that the solution should use that. A bonus solution using Swift Concurrency wouldn't hurt as I will probably switch over sometime in the future, but won't be able to switch soon.
I have written code that can retrieve the Spotlight data as the [String], but I don't know how to return it synchronously from a function; whatever I tried, the query hangs, presumably because I've called various run loop functions at the wrong places.
In case it matters, the app is a macOS command-line app using Swift 5.7 & Swift Argument Parser 1.5.0. The Spotlight data will be output only as text to stdout & stderr, not to any Apple UI elements.
MacOS Version: 14.7.2
macOS SDKs:
macOS 14.5 -sdk macosx14.5
I am working on a sample program for validation Against:
Team Identifier
Developer ID
I started with validating Team Identifier, but my validation is not working and it is allowing to launch programs which are not matching the team identifier in the signature.
Below is my code:
func verifyExecutableWithLCR(executablePath: String, arguments: [String]) -> Bool {
let task = Process()
task.launchPath = executablePath
task.arguments = arguments
if #available(macOS 14.4, *) {
print("launchRequirementData is available on this system.")
do {
let req = try OnDiskCodeRequirement.allOf {
TeamIdentifier("ABCDEFGHI")
//SigningIdentifier("com.***.client.***-Client.****")
}
let encoder = PropertyListEncoder()
encoder.outputFormat = .xml
let requirementData = try encoder.encode(req)
task.launchRequirementData = requirementData
print("launchRequirementData is set.")
try task.run()
print("[SUCCESS] Executable passed the code signature verification.")
return true
} catch {
print("[ERROR] Code signature verification failed: \(error.localizedDescription)")
return false
}
} else {
print("[WARNING] launchRequirement is not available on this macOS version.")
return false
}
}
Could you please help me in identifying whay am I doing wrong here?
I'm trying to launch a command line app from my objective C application (sandboxed) using NSTask and I keep getting "launch path not accessible"
Here is the path:
[task setLaunchPath:@"/usr/local/bin/codeview"];
I have set the appropriate attributes for codeview and it is working perfectly when I use it from the command line and /usr/local/bin IS in the $PATH
I know I have NSTask configured correctly because this WILL work:
[task setLaunchPath:@"/usr/bin/hexdump"];
With the exception being that I'm using a command already in /usr/bin. But I can't copy codeview into /usr/bin due to SIPS.
I've tried moving codeview to various other non-SIPS protected locations all to no avail. Must all NSTask commands come from /usr/bin? Where might I put codeview so that it can be launched.
Today I'm going to use an older computer and disable SIPS to put my command in /usr/bin and see if that works. If it does. I will do it on my main machine.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Entitlements
Objective-C
Command Line Tools
App Sandbox
Hi! I'm trying to submit a task request into BGTaskScheduler when I background my app. The backgrounding triggers an update of data to a shared app groups container. I'm currently getting the following error and unsure where it's coming from:
*** Assertion failure in -[BGTaskScheduler _unsafe_submitTaskRequest:error:], BGTaskScheduler.m:274
Here is my code:
BGAppRefreshTaskRequest *request = [[BGAppRefreshTaskRequest alloc] initWithIdentifier:kRBBackgroundTaskIdentifier];
NSError *error = nil;
bool success = [[BGTaskScheduler sharedScheduler] submitTaskRequest:request error:&error];
I'm developing a medication scheduling app similar to Apple Health's Medications feature, and I'd like some input on my current approach to background tasks.
In my app, when a user creates a medication, I generate ScheduledDose objects (with corresponding local notifications) for the next 2 weeks and save them to SwiftData. To ensure this 2-week window stays current, I've implemented a BGAppRefreshTask that runs daily to generate new doses as needed.
My concern is whether BGAppRefreshTask is the appropriate mechanism for this purpose. Since I'm not making any network requests but rather generating and storing local data, I'm questioning if this is the right approach.
I'm also wondering how Apple Health's Medications feature handles this kind of scheduling. Their app seems to maintain future doses regardless of app usage patterns.
Has anyone implemented something similar or can suggest the best background execution API for this type of scenario?
Thanks for any guidance you can provide.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
HealthKit
SwiftUI
Background Tasks
SwiftData
Hi everyone, I’m Jaswanth. My friends and I are students working on a project where we’ve developed a website and a companion app.
Here’s the key functionality:
When two users enter a virtual room, one of them is prompted to download a desktop app.
The app is built with Python and uses psutil to check for certain running processes.
It does not send any data over the internet.
It has a GUI that clearly shows the system is being monitored , it’s not hidden or running in the background silently.
We want to sign and notarize the app to make sure it runs on macOS without warning users. However, we’re concerned that since the app accesses system process information, it might be flagged as malicious.
Before we pay for the Apple Developer Program, we wanted to ask:
Will an app like this (which only reads running processes and does not exfiltrate or hide activity) be eligible for notarization?
Thanks in advance for any insights. We'd appreciate any clarity before moving forward.
Best,
Jaswanth
My app is for personal use currently, so distribution won't be a problem. It registers a privileged helper using SMAppService, and I was wondering whether there is a way to customize the authorization dialog that the system presents to the user.