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New features for APNs token authentication now available
Team-scoped keys introduce the ability to restrict your token authentication keys to either development or production environments. Topic-specific keys in addition to environment isolation allow you to associate each key with a specific Bundle ID streamlining key management. For detailed instructions on accessing these features, read our updated documentation on establishing a token-based connection to APNs.
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1.8k
Feb ’25
How to turn off shortcuts notifications permanently apart from turning it off via screen time as it keeps turning itself back ON.
I have created a configuration profile which basically just turns off notifications for Shortcuts app but I am unable to install it on my iPhone as I am getting the following error “This profile can be installed on a supervised device only” can someone please help me with this? Would also appreciate if you have another way to turn off shortcuts notifications permanently since when I turn it off via screen time it keeps turning itself ON every couple of days.
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301
Feb ’25
Background App wake up when Live Activity Offline Push Arrived not reliable
we have three problem when using the push notification on Live Activity. 1. What is the specific callback strategy for the activityUpdates property in ActivityKit? We found that in actual user scenarios, there is a probability that we may not receive callbacks. From the community experience, there are some resource optimization strategies that do not perform callbacks. From this perspective, the explanation is kind of vague. Is there any clear feedback to understand why callbacks are performed/not performed? 2.what is the specific description of the wake-up strategy, when background app receive Live Activity offline start Push? From community experience, we can see that the system may wake up for a duration of 0-30s due to resource optimization strategies, or not wake up/not deal with it. Is there an official description of the wake-up strategy? or we also have to follow this description: Wake up of apps using content-available pushes are heavily throttled. You can expect 1-2 wakeup per hour as a best case scenario in the hands of your users. so this cannot be assumed to be a reliable wake-up on demand mechanism for an app. 3 How can we determine user have selected (allow or always allow) of the Live Activity permission? When we use real-time activity offline push, there are two system prompts in iOS: the first prompt : allow and disallow real-time activity the second prompt : always allow and disallow Is there an interface that can directly determine which permission the user has chosen (allow/always allow)? (By the way, we can get disallow status). At present, we haven't seen any interface in the official documentation/interface that can determine (allow/always allow). The difference here will affect the generation of Update Token. Without Update Token, we can not update our activity instance.
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664
Feb ’25
Offline Mapkit tiles
I'm currently developing an app with mapkit which I may submit to the Swift Student Challenge. So anyways, the app will be used completely offline. I was wondering if there was any way to include very low resolution map tiles with the app files. That way, the app never needs wifi. However, I'm not sure if this is possible, especially since the map would need to be under 20 mb. Thanks.
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308
Feb ’25
Apple Pay Wallet API Access – Applied a Year AGO and Almost No Progress! Anyone Else?
Hey everyone, I wanted to check if anyone else has faced extreme delays when requesting access to Apple Pay Wallet APIs. It was Oct 11 2024 a year ago since we first applied to enable in-app provisioning for virtual cards in our app and we made 1% progress. For context, we already got access from Google for Google Wallet—it was smooth, professional, and timely. But with Apple… it’s been nothing but an endless cycle of waiting. We followed every step, submitted everything correctly, and even called Apple Developer Support multiple times. Their response? "We've escalated it." Again and again. But there’s no real progress. We’re rerouted, ignored, and left in limbo. At this point, I don’t even know if anyone is actually reviewing these requests. If a business like ours—fully compliant and ready to integrate—can’t even get a response in 150 day, how is this process supposed to work? I’m posting this here because I can’t be the only one. Has anyone else faced this? If you finally got access, how did you do it? Because right now, it feels like Apple Pay in-app provisioning is an impossible goal. Hoping someone from Apple sees this and realizes how broken this process is. We’re just trying to innovate and offer Apple users a great experience—why is it so difficult? Looking forward to hearing from anyone in the community who can help, Thanks! 🙏
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335
Feb ’25
Merchant validation error on Apple Pay payment processing
Hi, I'm developer in fintech company, we have setup process for onboarding merchants for our partner and processing payments with usage of Apple Pay API. Daily system is processing ca. 10k payments but every day ca. 100 of transactions are declined because of merchant validation error: request to https://apple-pay-gateway.apple.com/paymentservices/paymentSession (with all required parameters in body) is returning response with status code 417 "statusMessage": "Payment Services Exception merchantId={root merchant id} unauthorized to process transactions on behalf of merchantId={merchant id hash} reason={merchant id hash} is not a registered merchant in WWDR and isn't properly authorized via Mass Enablement, either." Issue impacts recurring merchants, most of their transactions are processed successfully but randomly some of them are failing with such reason. All prerequisites are met: merchant have deployed 'apple-developer-merchantid-domain-association' certificate, certificates are valid and not expired. Apple Support is not able to provide any information based on provided requests timestamps. We would to know what may be the reason just part of the requests are failing and what 417 error code means.
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274
Feb ’25
Is the Time Sensitive Notification entitlement needed for visionOS?
I noticed the time sensitive entitlement says it's only for iOS and macOS. But without the entitlement, the time sensitive toggle doesn't show in my app's notification settings on visionOS. When I archive my visionOS app for App Store Connect, the entitlement seems to be taken out as it doesn't show in my entitlement list for the build in App Store Connect. I'm confused at this point if the entitlement is really necessary, since it seems to be needed to debug on the simulator at least. I don't have a physical device to test it on unfortunately.
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396
Feb ’25
My MacOS swift app refuses to close (When running on Monterrey, The app becomes unresponsive after it finishes all its work, and needs to be forcefully closed)
My MacOS swift app [myStuckApp5] refuses to close when running on Monterrey (The app becomes unresponsive after finishing its work, and needs to be forcefully closed). However, it closes as expected when running MacOS 13 and above. How can I troubleshoot this error? I'm attaching the content of the sys Log related to the app while it was stuck (too long to copy here...) This is the content of the related sys Log
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485
Feb ’25
Accessing Full Apple Pay Transaction Data in AppIntents
I'm currently working on an AppIntent in my app to import Apple Pay transactions via Transaction triggers in Shortcuts. While I can access the transaction name with the following code: @Parameter(title: "Transaction") var transaction: String I'm not sure how to retrieve the full details of the transaction, including: Card or Pass Merchant Amount Name At the moment, transaction only provides the name as a string, but I need access to the complete transaction data. I know that by selecting specific fields like Amount, Merchant, etc., I can retrieve each piece of data individually, but it would be much easier and more user-friendly to simply retrieve the entire transaction object at once. Has anyone successfully retrieved all details of an Apple Pay transaction in this context, and if so, could you share how to do so?
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415
Feb ’25
Moving from Multipeer Connectivity to Network Framework
I see a lot of folks spend a lot of time trying to get Multipeer Connectivity to work for them. My experience is that the final result is often unsatisfactory. Instead, my medium-to-long term recommendation is to use Network framework instead. This post explains how you might move from Multipeer Connectivity to Network framework. If you have questions or comments, put them in a new thread. Place it in the App & System Services > Networking topic area and tag it with Multipeer Connectivity and Network framework. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Moving from Multipeer Connectivity to Network Framework Multipeer Connectivity has a number of drawbacks: It has an opinionated networking model, where every participant in a session is a symmetric peer. Many apps work better with the traditional client/server model. It offers good latency but poor throughput. It doesn’t support flow control, aka back pressure, which severely constrains its utility for general-purpose networking. It includes a number of UI components that are effectively obsolete. It hasn’t evolved in recent years. For example, it relies on NSStream, which has been scheduled for deprecation as far as networking is concerned. It always enables peer-to-peer Wi-Fi, something that’s not required for many apps and can impact the performance of the network (see Enable peer-to-peer Wi-Fi, below, for more about this). Its security model requires the use of PKI — public key infrastructure, that is, digital identities and certificates — which are tricky to deploy in a peer-to-peer environment. It has some gnarly bugs. IMPORTANT Many folks use Multipeer Connectivity because they think it’s the only way to use peer-to-peer Wi-Fi. That’s not the case. Network framework has opt-in peer-to-peer Wi-Fi support. See Enable peer-to-peer Wi-Fi, below. If Multipeer Connectivity is not working well for you, consider moving to Network framework. This post explains how to do that in 13 easy steps (-: Plan for security Select a network architecture Create a peer identifier Choose a protocol to match your send mode Discover peers Design for privacy Configure your connections Manage a listener Manage a connection Send and receive reliable messages Send and receive best effort messages Start a stream Send a resource Finally, at the end of the post you’ll find two appendices: Final notes contains some general hints and tips. Symbol cross reference maps symbols in the Multipeer Connectivity framework to sections of this post. Consult it if you’re not sure where to start with a specific Multipeer Connectivity construct. Plan for security The first thing you need to think about is security. Multipeer Connectivity offers three security models, expressed as choices in the MCEncryptionPreference enum: .none for no security .optional for optional security .required for required security For required security each peer must have a digital identity. Optional security is largely pointless. It’s more complex than no security but doesn’t yield any benefits. So, in this post we’ll focus on the no security and required security models. Your security choice affects the network protocols you can use: QUIC is always secure. WebSocket, TCP, and UDP can be used with and without TLS security. QUIC security only supports PKI. TLS security supports both TLS-PKI and pre-shared key (PSK). You might find that TLS-PSK is easier to deploy in a peer-to-peer environment. To configure the security of the QUIC protocol: func quicParameters() -> NWParameters { let quic = NWProtocolQUIC.Options(alpn: ["MyAPLN"]) let sec = quic.securityProtocolOptions … configure `sec` here … return NWParameters(quic: quic) } To enable TLS over TCP: func tlsOverTCPParameters() -> NWParameters { let tcp = NWProtocolTCP.Options() let tls = NWProtocolTLS.Options() let sec = tls.securityProtocolOptions … configure `sec` here … return NWParameters(tls: tls, tcp: tcp) } To enable TLS over UDP, also known as DTLS: func dtlsOverUDPParameters() -> NWParameters { let udp = NWProtocolUDP.Options() let dtls = NWProtocolTLS.Options() let sec = dtls.securityProtocolOptions … configure `sec` here … return NWParameters(dtls: dtls, udp: udp) } To configure TLS with a local digital identity and custom server trust evaluation: func configureTLSPKI(sec: sec_protocol_options_t, identity: SecIdentity) { let secIdentity = sec_identity_create(identity)! sec_protocol_options_set_local_identity(sec, secIdentity) if disableServerTrustEvaluation { sec_protocol_options_set_verify_block(sec, { metadata, secTrust, completionHandler in let trust = sec_trust_copy_ref(secTrust).takeRetainedValue() … evaluate `trust` here … completionHandler(true) }, .main) } } To configure TLS with a pre-shared key: func configureTLSPSK(sec: sec_protocol_options_t, identity: Data, key: Data) { let identityDD = identity.withUnsafeBytes { DispatchData(bytes: $0) } let keyDD = identity.withUnsafeBytes { DispatchData(bytes: $0) } sec_protocol_options_add_pre_shared_key( sec, keyDD as dispatch_data_t, identityDD as dispatch_data_t ) sec_protocol_options_append_tls_ciphersuite( sec, tls_ciphersuite_t(rawValue: TLS_PSK_WITH_AES_128_GCM_SHA256)! ) } Select a network architecture Multipeer Connectivity uses a star network architecture. All peers are equal, and every peer is effectively connected to every peer. Many apps work better with the client/server model, where one peer acts on the server and all the others are clients. Network framework supports both models. To implement a client/server network architecture with Network framework: Designate one peer as the server and all the others as clients. On the server, use NWListener to listen for incoming connections. On each client, use NWConnection to made an outgoing connection to the server. To implement a star network architecture with Network framework: On each peer, start a listener. And also start a connection to each of the other peers. This is likely to generate a lot of redundant connections, as peer A connects to peer B and vice versa. You’ll need to a way to deduplicate those connections, which is the subject of the next section. IMPORTANT While the star network architecture is more likely to create redundant connections, the client/server network architecture can generate redundant connections as well. The advice in the next section applies to both architectures. Create a peer identifier Multipeer Connectivity uses MCPeerID to uniquely identify each peer. There’s nothing particularly magic about MCPeerID; it’s effectively a wrapper around a large random number. To identify each peer in Network framework, generate your own large random number. One good choice for a peer identifier is a locally generated UUID, created using the system UUID type. Some Multipeer Connectivity apps persist their local MCPeerID value, taking advantage of its NSSecureCoding support. You can do the same with a UUID, using either its string representation or its Codable support. IMPORTANT Before you decide to persist a peer identifier, think about the privacy implications. See Design for privacy below. Avoid having multiple connections between peers; that’s both wasteful and potentially confusing. Use your peer identifier to deduplicate connections. Deduplicating connections in a client/server network architecture is easy. Have each client check in with the server with its peer identifier. If the server already has a connection for that identifier, it can either close the old connection and keep the new connection, or vice versa. Deduplicating connections in a star network architecture is a bit trickier. One option is to have each peer send its peer identifier to the other peer and then the peer with the ‘best’ identifier wins. For example, imagine that peer A makes an outgoing connection to peer B while peer B is simultaneously making an outgoing connection to peer A. When a peer receives a peer identifier from a connection, it checks for a duplicate. If it finds one, it compares the peer identifiers and then chooses a connection to drop based on that comparison: if local peer identifier > remote peer identifier then drop outgoing connection else drop incoming connection end if So, peer A drops its incoming connection and peer B drops its outgoing connection. Et voilà! Choose a protocol to match your send mode Multipeer Connectivity offers two send modes, expressed as choices in the MCSessionSendDataMode enum: .reliable for reliable messages .unreliable for best effort messages Best effort is useful when sending latency-sensitive data, that is, data where retransmission is pointless because, by the retransmission arrives, the data will no longer be relevant. This is common in audio and video applications. In Network framework, the send mode is set by the connection’s protocol: A specific QUIC connection is either reliable or best effort. WebSocket and TCP are reliable. UDP is best effort. Start with a reliable connection. In many cases you can stop there, because you never need a best effort connection. If you’re not sure which reliable protocol to use, choose WebSocket. It has key advantages over other protocols: It supports both security models: none and required. Moreover, its required security model supports both TLS-PKI and TLS PSK. In contrast, QUIC only supports the required security model, and within that model it only supports TLS-PKI. It allows you to send messages over the connection. In contrast, TCP works in terms of bytes, meaning that you have to add your own framing. If you need a best effort connection, get started with a reliable connection and use that connection to set up a parallel best effort connection. For example, you might have an exchange like this: Peer A uses its reliable WebSocket connection to peer B to send a request for a parallel best effort UDP connection. Peer B receives that, opens a UDP listener, and sends the UDP listener’s port number back to peer A. Peer A opens its parallel UDP connection to that port on peer B. Note For step 3, get peer B’s IP address from the currentPath property of the reliable WebSocket connection. If you’re not sure which best effort protocol to use, use UDP. While it is possible to use QUIC in datagram mode, it has the same security complexities as QUIC in reliable mode. Discover peers Multipeer Connectivity has a types for advertising a peer’s session (MCAdvertiserAssistant) and a type for browsering for peer (MCNearbyServiceBrowser). In Network framework, configure the listener to advertise its service by setting the service property of NWListener: let listener: NWListener = … listener.service = .init(type: "_example._tcp") listener.serviceRegistrationUpdateHandler = { change in switch change { case .add(let endpoint): … update UI for the added listener endpoint … break case .remove(let endpoint): … update UI for the removed listener endpoint … break @unknown default: break } } listener.stateUpdateHandler = … handle state changes … listener.newConnectionHandler = … handle the new connection … listener.start(queue: .main) This example also shows how to use the serviceRegistrationUpdateHandler to update your UI to reflect changes in the listener. Note This example uses a service type of _example._tcp. See About service types, below, for more details on that. To browse for services, use NWBrowser: let browser = NWBrowser(for: .bonjour(type: "_example._tcp", domain: nil), using: .tcp) browser.browseResultsChangedHandler = { latestResults, _ in … update UI to show the latest results … } browser.stateUpdateHandler = … handle state changes … browser.start(queue: .main) This yields NWEndpoint values for each peer that it discovers. To connect to a given peer, create an NWConnection with that endpoint. About service types The examples in this post use _example._tcp for the service type. The first part, _example, is directly analogous to the serviceType value you supply when creating MCAdvertiserAssistant and MCNearbyServiceBrowser objects. The second part is either _tcp or _udp depending on the underlying transport protocol. For TCP and WebSocket, use _tcp. For UDP and QUIC, use _udp. Service types are described in RFC 6335. If you deploy an app that uses a new service type, register that service type with IANA. Discovery UI Multipeer Connectivity also has UI components for advertising (MCNearbyServiceAdvertiser) and browsing (MCBrowserViewController). There’s no direct equivalent to this in Network framework. Instead, use your preferred UI framework to create a UI that best suits your requirements. Note If you’re targeting Apple TV, check out the DeviceDiscoveryUI framework. Discovery TXT records The Bonjour service discovery protocol used by Network framework supports TXT records. Using these, a listener can associate metadata with its service and a browser can get that metadata for each discovered service. To advertise a TXT record with your listener, include it it the service property value: let listener: NWListener = … let peerID: UUID = … var txtRecord = NWTXTRecord() txtRecord["peerID"] = peerID.uuidString listener.service = .init(type: "_example._tcp", txtRecord: txtRecord.data) To browse for services and their associated TXT records, use the .bonjourWithTXTRecord(…) descriptor: let browser = NWBrowser(for: .bonjourWithTXTRecord(type: "_example._tcp", domain: nil), using: .tcp) browser.browseResultsChangedHandler = { latestResults, _ in for result in latestResults { guard case .bonjour(let txtRecord) = result.metadata, let peerID = txtRecord["peerID"] else { continue } // … examine `result` and `peerID` … _ = peerID } } This example includes the peer identifier in the TXT record with the goal of reducing the number of duplicate connections, but that’s just one potential use for TXT records. Design for privacy This section lists some privacy topics to consider as you implement your app. Obviously this isn’t an exhaustive list. For general advice on this topic, see Protecting the User’s Privacy. There can be no privacy without security. If you didn’t opt in to security with Multipeer Connectivity because you didn’t want to deal with PKI, consider the TLS-PSK options offered by Network framework. For more on this topic, see Plan for security. When you advertise a service, the default behaviour is to use the user-assigned device name as the service name. To override that, create a service with a custom name: let listener: NWListener = … let name: String = … listener.service = .init(name: name, type: "_example._tcp") It’s not uncommon for folks to use the peer identifier as the service name. Whether that’s a good option depends on the user experience of your product: Some products present a list of remote peers and have the user choose from that list. In that case it’s best to stick with the user-assigned device name, because that’s what the user will recognise. Some products automatically connect to services as they discover them. In that case it’s fine to use the peer identifier as the service name, because the user won’t see it anyway. If you stick with the user-assigned device name, consider advertising the peer identifier in your TXT record. See Discovery TXT records. IMPORTANT Using a peer identifier in your service name or TXT record is a heuristic to reduce the number of duplicate connections. Don’t rely on it for correctness. Rather, deduplicate connections using the process described in Create a peer identifier. There are good reasons to persist your peer identifier, but doing so isn’t great for privacy. Persisting the identifier allows for tracking of your service over time and between networks. Consider whether you need a persistent peer identifier at all. If you do, consider whether it makes sense to rotate it over time. A persistent peer identifier is especially worrying if you use it as your service name or put it in your TXT record. Configure your connections Multipeer Connectivity’s symmetric architecture means that it uses a single type, MCSession, to manage the connections to all peers. In Network framework, that role is fulfilled by two types: NWListener to listen for incoming connections. NWConnection to make outgoing connections. Both types require you to supply an NWParameters value that specifies the network protocol and options to use. In addition, when creating an NWConnection you pass in an NWEndpoint to tell it the service to connect to. For example, here’s how to configure a very simple listener for TCP: let parameters = NWParameters.tcp let listener = try NWListener(using: parameters) … continue setting up the listener … And here’s how you might configure an outgoing TCP connection: let parameters = NWParameters.tcp let endpoint = NWEndpoint.hostPort(host: "example.com", port: 80) let connection = NWConnection.init(to: endpoint, using: parameters) … continue setting up the connection … NWParameters has properties to control exactly what protocol to use and what options to use with those protocols. To work with QUIC connections, use code like that shown in the quicParameters() example from the Security section earlier in this post. To work with TCP connections, use the NWParameters.tcp property as shown above. To enable TLS on your TCP connections, use code like that shown in the tlsOverTCPParameters() example from the Security section earlier in this post. To work with WebSocket connections, insert it into the application protocols array: let parameters = NWParameters.tcp let ws = NWProtocolWebSocket.Options(.version13) parameters.defaultProtocolStack.applicationProtocols.insert(ws, at: 0) To enable TLS on your WebSocket connections, use code like that shown in the tlsOverTCPParameters() example to create your base parameters and then add the WebSocket application protocol to that. To work with UDP connections, use the NWParameters.udp property: let parameters = NWParameters.udp To enable TLS on your UDP connections, use code like that shown in the dtlsOverUDPParameters() example from the Security section earlier in this post. Enable peer-to-peer Wi-Fi By default, Network framework doesn’t use peer-to-peer Wi-Fi. To enable that, set the includePeerToPeer property on the parameters used to create your listener and connection objects. parameters.includePeerToPeer = true IMPORTANT Enabling peer-to-peer Wi-Fi can impact the performance of the network. Only opt into it if it’s a significant benefit to your app. If you enable peer-to-peer Wi-Fi, it’s critical to stop network operations as soon as you’re done with them. For example, if you’re browsing for services with peer-to-peer Wi-Fi enabled and the user picks a service, stop the browse operation immediately. Otherwise, the ongoing browse operation might affect the performance of your connection. Manage a listener In Network framework, use NWListener to listen for incoming connections: let parameters: NWParameters = .tcp … configure parameters … let listener = try NWListener(using: parameters) listener.service = … service details … listener.serviceRegistrationUpdateHandler = … handle service registration changes … listener.stateUpdateHandler = { newState in … handle state changes … } listener.newConnectionHandler = { newConnection in … handle the new connection … } listener.start(queue: .main) For details on how to set up parameters, see Configure your connections. For details on how to set up up service and serviceRegistrationUpdateHandler, see Discover peers. Network framework calls your state update handler when the listener changes state: let listener: NWListener = … listener.stateUpdateHandler = { newState in switch newState { case .setup: // The listener has not yet started. … case .waiting(let error): // The listener tried to start and failed. It might recover in the // future. … case .ready: // The listener is running. … case .failed(let error): // The listener tried to start and failed irrecoverably. … case .cancelled: // The listener was cancelled by you. … @unknown default: break } } Network framework calls your new connection handler when a client connects to it: var connections: [NWConnection] = [] let listener: NWListener = listener listener.newConnectionHandler = { newConnection in … configure the new connection … newConnection.start(queue: .main) connections.append(newConnection) } IMPORTANT Don’t forget to call start(queue:) on your connections. In Multipeer Connectivity, the session (MCSession) keeps track of all the peers you’re communicating with. With Network framework, that responsibility falls on you. This example uses a simple connections array for that purpose. In your app you may or may not need a more complex data structure. For example: In the client/server network architecture, the client only needs to manage the connections to a single peer, the server. On the other hand, the server must managed the connections to all client peers. In the star network architecture, every peer must maintain a listener and connections to each of the other peers. Understand UDP flows Network framework handles UDP using the same NWListener and NWConnection types as it uses for TCP. However, the underlying UDP protocol is not implemented in terms of listeners and connections. To resolve this, Network framework works in terms of UDP flows. A UDP flow is defined as a bidirectional sequence of UDP datagrams with the same 4 tuple (local IP address, local port, remote IP address, and remote port). In Network framework: Each NWConnection object manages a single UDP flow. If an NWListener receives a UDP datagram whose 4 tuple doesn’t match any known NWConnection, it creates a new NWConnection. Manage a connection In Network framework, use NWConnection to start an outgoing connection: var connections: [NWConnection] = [] let parameters: NWParameters = … let endpoint: NWEndpoint = … let connection = NWConnection(to: endpoint, using: parameters) connection.stateUpdateHandler = … handle state changes … connection.viabilityUpdateHandler = … handle viability changes … connection.pathUpdateHandler = … handle path changes … connection.betterPathUpdateHandler = … handle better path notifications … connection.start(queue: .main) connections.append(connection) As in the listener case, you’re responsible for keeping track of this connection. Each connection supports four different handlers. Of these, the state and viability update handlers are the most important. For information about the path update and better path handlers, see the NWConnection documentation. Network framework calls your state update handler when the connection changes state: let connection: NWConnection = … connection.stateUpdateHandler = { newState in switch newState { case .setup: // The connection has not yet started. … case .preparing: // The connection is starting. … case .waiting(let error): // The connection tried to start and failed. It might recover in the // future. … case .ready: // The connection is running. … case .failed(let error): // The connection tried to start and failed irrecoverably. … case .cancelled: // The connection was cancelled by you. … @unknown default: break } } If you a connection is in the .waiting(_:) state and you want to force an immediate retry, call the restart() method. Network framework calls your viability update handler when its viability changes: let connection: NWConnection = … connection.viabilityUpdateHandler = { isViable in … react to viability changes … } A connection becomes inviable when a network resource that it depends on is unavailable. A good example of this is the network interface that the connection is running over. If you have a connection running over Wi-Fi, and the user turns off Wi-Fi or moves out of range of their Wi-Fi network, any connection running over Wi-Fi becomes inviable. The inviable state is not necessarily permanent. To continue the above example, the user might re-enable Wi-Fi or move back into range of their Wi-Fi network. If the connection becomes viable again, Network framework calls your viability update handler with a true value. It’s a good idea to debounce the viability handler. If the connection becomes inviable, don’t close it down immediately. Rather, wait for a short while to see if it becomes viable again. If a connection has been inviable for a while, you get to choose as to how to respond. For example, you might close the connection down or inform the user. To close a connection, call the cancel() method. This gracefully disconnects the underlying network connection. To close a connection immediately, call the forceCancel() method. This is not something you should do as a matter of course, but it does make sense in exceptional circumstances. For example, if you’ve determined that the remote peer has gone deaf, it makes sense to cancel it in this way. Send and receive reliable messages In Multipeer Connectivity, a single session supports both reliable and best effort send modes. In Network framework, a connection is either reliable or best effort, depending on the underlying network protocol. The exact mechanism for sending a message depends on the underlying network protocol. A good protocol for reliable messages is WebSocket. To send a message on a WebSocket connection: let connection: NWConnection = … let message: Data = … let metadata = NWProtocolWebSocket.Metadata(opcode: .binary) let context = NWConnection.ContentContext(identifier: "send", metadata: [metadata]) connection.send(content: message, contentContext: context, completion: .contentProcessed({ error in // … check `error` … _ = error })) In WebSocket, the content identifier is ignored. Using an arbitrary fixed value, like the send in this example, is just fine. Multipeer Connectivity allows you to send a message to multiple peers in a single send call. In Network framework each send call targets a specific connection. To send a message to multiple peers, make a send call on the connection associated with each peer. If your app needs to transfer arbitrary amounts of data on a connection, it must implement flow control. See Start a stream, below. To receive messages on a WebSocket connection: func startWebSocketReceive(on connection: NWConnection) { connection.receiveMessage { message, _, _, error in if let error { … handle the error … return } if let message { … handle the incoming message … } startWebSocketReceive(on: connection) } } IMPORTANT WebSocket preserves message boundaries, which is one of the reasons why it’s ideal for your reliable messaging connections. If you use a streaming protocol, like TCP or QUIC streams, you must do your own framing. A good way to do that is with NWProtocolFramer. If you need the metadata associated with the message, get it from the context parameter: connection.receiveMessage { message, context, _, error in … if let message, let metadata = context?.protocolMetadata(definition: NWProtocolWebSocket.definition) as? NWProtocolWebSocket.Metadata { … handle the incoming message and its metadata … } … } Send and receive best effort messages In Multipeer Connectivity, a single session supports both reliable and best effort send modes. In Network framework, a connection is either reliable or best effort, depending on the underlying network protocol. The exact mechanism for sending a message depends on the underlying network protocol. A good protocol for best effort messages is UDP. To send a message on a UDP connection: let connection: NWConnection = … let message: Data = … connection.send(content: message, completion: .idempotent) IMPORTANT UDP datagrams have a theoretical maximum size of just under 64 KiB. However, sending a large datagram results in IP fragmentation, which is very inefficient. For this reason, Network framework prevents you from sending UDP datagrams that will be fragmented. To find the maximum supported datagram size for a connection, gets its maximumDatagramSize property. To receive messages on a UDP connection: func startUDPReceive(on connection: NWConnection) { connection.receiveMessage { message, _, _, error in if let error { … handle the error … return } if let message { … handle the incoming message … } startUDPReceive(on: connection) } } This is exactly the same code as you’d use for WebSocket. Start a stream In Multipeer Connectivity, you can ask the session to start a stream to a specific peer. There are two ways to achieve this in Network framework: If you’re using QUIC for your reliable connection, start a new QUIC stream over that connection. This is one place that QUIC shines. You can run an arbitrary number of QUIC connections over a single QUIC connection group, and QUIC manages flow control (see below) for each connection and for the group as a whole. If you’re using some other protocol for your reliable connection, like WebSocket, you must start a new connection. You might use TCP for this new connection, but it’s not unreasonable to use WebSocket or QUIC. If you need to open a new connection for your stream, you can manage that process over your reliable connection. Choose a protocol to match your send mode explains the general approach for this, although in that case it’s opening a parallel best effort UDP connection rather than a parallel stream connection. The main reason to start a new stream is that you want to send a lot of data to the remote peer. In that case you need to worry about flow control. Flow control applies to both the send and receive side. IMPORTANT Failing to implement flow control can result in unbounded memory growth in your app. This is particularly bad on iOS, where jetsam will terminate your app if it uses too much memory. On the send side, implement flow control by waiting for the connection to call your completion handler before generating and sending more data. For example, on a TCP connection or QUIC stream you might have code like this: func sendNextChunk(on connection: NWConnection) { let chunk: Data = … read next chunk from disk … connection.send(content: chunk, completion: .contentProcessed({ error in if let error { … handle error … return } sendNextChunk(on: connection) })) } This acts like an asynchronous loop. The first send call completes immediately because the connection just copies the data to its send buffer. In response, your app generates more data. This continues until the connection’s send buffer fills up, at which point it defers calling your completion handler. Eventually, the connection moves enough data across the network to free up space in its send buffer, and calls your completion handler. Your app generates another chunk of data For best performance, use a chunk size of at least 64 KiB. If you’re expecting to run on a fast device with a fast network, a chunk size of 1 MiB is reasonable. Receive-side flow control is a natural extension of the standard receive pattern. For example, on a TCP connection or QUIC stream you might have code like this: func receiveNextChunk(on connection: NWConnection) { let chunkSize = 64 * 1024 connection.receive(minimumIncompleteLength: chunkSize, maximumLength: chunkSize) { chunk, _, isComplete, error in if let chunk { … write chunk to disk … } if isComplete { … close the file … return } if let error { … handle the error … return } receiveNextChunk(on: connection) } } IMPORTANT The above is cast in terms of writing the chunk to disk. That’s important, because it prevents unbounded memory growth. If, for example, you accumulated the chunks into an in-memory buffer, that buffer could grow without bound, which risks jetsam terminating your app. The above assumes that you can read and write chunks of data synchronously and promptly, for example, reading and writing a file on a local disk. That’s not always the case. For example, you might be writing data to an accessory over a slow interface, like Bluetooth LE. In such cases you need to read and write each chunk asynchronously. This results in a structure where you read from an asynchronous input and write to an asynchronous output. For an example of how you might approach this, albeit in a very different context, see Handling Flow Copying. Send a resource In Multipeer Connectivity, you can ask the session to send a complete resource, identified by either a file or HTTP URL, to a specific peer. Network framework has no equivalent support for this, but you can implement it on top of a stream: To send, open a stream and then read chunks of data using URLSession and send them over that stream. To receive, open a stream and then receive chunks of data from that stream and write those chunks to disk. In this situation it’s critical to implement flow control, as described in the previous section. Final notes This section collects together some general hints and tips. Concurrency In Multipeer Connectivity, each MCSession has its own internal queue and calls delegate callbacks on that queue. In Network framework, you get to control the queue used by each object for its callbacks. A good pattern is to have a single serial queue for all networking, including your listener and all connections. In a simple app it’s reasonable to use the main queue for networking. If you do this, be careful not to do CPU intensive work in your networking callbacks. For example, if you receive a message that holds JPEG data, don’t decode that data on the main queue. Overriding protocol defaults Many network protocols, most notably TCP and QUIC, are intended to be deployed at vast scale across the wider Internet. For that reason they use default options that aren’t optimised for local networking. Consider changing these defaults in your app. TCP has the concept of a send timeout. If you send data on a TCP connection and TCP is unable to successfully transfer it to the remote peer within the send timeout, TCP will fail the connection. The default send timeout is infinite. TCP just keeps trying. To change this, set the connectionDropTime property. TCP has the concept of keepalives. If a connection is idle, TCP will send traffic on the connection for two reasons: If the connection is running through a NAT, the keepalives prevent the NAT mapping from timing out. If the remote peer is inaccessible, the keepalives fail, which in turn causes the connection to fail. This prevents idle but dead connections from lingering indefinitely. TCP keepalives default to disabled. To enable and configure them, set the enableKeepalive property. To configure their behaviour, set the keepaliveIdle, keepaliveCount, and keepaliveInterval properties. Symbol cross reference If you’re not sure where to start with a specific Multipeer Connectivity construct, find it in the tables below and follow the link to the relevant section. [Sorry for the poor formatting here. DevForums doesn’t support tables properly, so I’ve included the tables as preformatted text.] | For symbol | See | | ----------------------------------- | --------------------------- | | `MCAdvertiserAssistant` | *Discover peers* | | `MCAdvertiserAssistantDelegate` | *Discover peers* | | `MCBrowserViewController` | *Discover peers* | | `MCBrowserViewControllerDelegate` | *Discover peers* | | `MCNearbyServiceAdvertiser` | *Discover peers* | | `MCNearbyServiceAdvertiserDelegate` | *Discover peers* | | `MCNearbyServiceBrowser` | *Discover peers* | | `MCNearbyServiceBrowserDelegate` | *Discover peers* | | `MCPeerID` | *Create a peer identifier* | | `MCSession` | See below. | | `MCSessionDelegate` | See below. | Within MCSession: | For symbol | See | | --------------------------------------------------------- | ------------------------------------ | | `cancelConnectPeer(_:)` | *Manage a connection* | | `connectedPeers` | *Manage a listener* | | `connectPeer(_:withNearbyConnectionData:)` | *Manage a connection* | | `disconnect()` | *Manage a connection* | | `encryptionPreference` | *Plan for security* | | `myPeerID` | *Create a peer identifier* | | `nearbyConnectionData(forPeer:withCompletionHandler:)` | *Discover peers* | | `securityIdentity` | *Plan for security* | | `send(_:toPeers:with:)` | *Send and receive reliable messages* | | `sendResource(at:withName:toPeer:withCompletionHandler:)` | *Send a resource* | | `startStream(withName:toPeer:)` | *Start a stream* | Within MCSessionDelegate: | For symbol | See | | ---------------------------------------------------------------------- | ------------------------------------ | | `session(_:didFinishReceivingResourceWithName:fromPeer:at:withError:)` | *Send a resource* | | `session(_:didReceive:fromPeer:)` | *Send and receive reliable messages* | | `session(_:didReceive:withName:fromPeer:)` | *Start a stream* | | `session(_:didReceiveCertificate:fromPeer:certificateHandler:)` | *Plan for security* | | `session(_:didStartReceivingResourceWithName:fromPeer:with:)` | *Send a resource* | | `session(_:peer:didChange:)` | *Manage a connection* | Revision History 2025-04-11 Added some advice as to whether to use the peer identifier in your service name. Expanded the discussion of how to deduplicate connections in a star network architecture. 2025-03-20 Added a link to the DeviceDiscoveryUI framework to the Discovery UI section. Made other minor editorial changes. 2025-03-11 Expanded the Enable peer-to-peer Wi-Fi section to stress the importance of stopping network operations once you’re done with them. Added a link to that section from the list of Multipeer Connectivity drawbacks. 2025-03-07 First posted.
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1.5k
Apr ’25
How can implement iOS esim in-app activation
Esim activation. Assuming I already have card data, I use the universal link https://esimsetup.apple.com/esim_qrcode_provisioning?carddata= to install it. However, it always ends up in the system Settings app. The flow: 1. Click the link -> 2. Redirect to Settings -> 3. Show activation dialog. Is there anyway to make the activation flow stay within the app? I couldn't find any documentation for that. This is an example from Revolut app, where the whole flow above happens without leaving the app.
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1
416
Feb ’25
Operation of Server Notifications V2 when Apple account is withdrawal
Please allow me to confirm the Server Notifications V2 specification. I am aware that if withdrawal an Apple account that has a subscription, the subscription will eventually be cancelled. Regarding Server Notifications V2 notifications with a notificationType of EXPIRED, am I correct in thinking that they will be sent when the subscription expires even if the Apple account is withdrawal?
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306
Feb ’25
UIApplication Background Task Notes
The UIApplication background task mechanism allows you to prevent your app from being suspended for short periods of time. While the API involved is quite small, there’s still a bunch of things to watch out for. The name background task is somewhat misappropriate. Specifically, beginBackgroundTask(expirationHandler:) doesn’t actually start any sort of background task, but rather it tells the system that you have started some ongoing work that you want to continue even if your app is in the background. You still have to write the code to create and manage that work. So it’s best to think of the background task API as raising a “don’t suspend me” assertion. You must end every background task that you begin. Failure to do so will result in your app being killed by the watchdog. For this reason I recommend that you attach a name to each background task you start (by calling beginBackgroundTask(withName:expirationHandler:) rather than beginBackgroundTask(expirationHandler:)). A good name is critical for tracking down problems when things go wrong. IMPORTANT Failing to end a background task is the number one cause of background task problems on iOS. This usually involves some easy-to-overlook error in bookkeeping that results in the app begining a background task and not ending it. For example, you might have a property that stores your current background task identifier (of type UIBackgroundTaskIdentifier). If you accidentally creates a second background task and store it in that property without calling endBackgroundTask on the identifier that’s currently stored there, the app will ‘leak’ a background task, something that will get it killed by the watchdog. One way to avoid this is to wrap the background task in an object; see the QRunInBackgroundAssertion post on this thread for an example. Background tasks can end in one of two ways: When your app has finished doing whatever it set out to do. When the system calls the task’s expiry handler. Your code is responsible for calling endBackgroundTask(_:) in both cases. All background tasks must have an expiry handler that the system can use to ‘call in’ the task. The background task API allows the system to do that at any time. Your expiry handler is your opportunity to clean things up. It should not return until everything is actually cleaned up. It must run quickly, that is, in less than a second or so. If it takes too long, your app will be killed by the watchdog. Your expiry handler is called on the main thread. It is legal to begin and end background tasks on any thread, but doing this from a secondary thread can be tricky because you have to coordinate that work with the expiry handler, which is always called on the main thread. The system puts strict limits on the total amount of time that you can prevent suspension using background tasks. On current systems you can expect about 30 seconds. IMPORTANT I’m quoting these numbers just to give you a rough idea of what to expect. The target values have changed in the past and may well change in the future, and the amount of time you actually get depends on the state of the system. The thing to remember here is that the exact value doesn’t matter as long as your background tasks have a functional expiry handler. You can get a rough estimate of the amount of time available to you by looking at UIApplication’s backgroundTimeRemaining property. IMPORTANT The value returned by backgroundTimeRemaining is an estimate and can change at any time. You must design your app to function correctly regardless of the value returned. It’s reasonable to use this property for debugging but we strongly recommend that you avoid using as part of your app’s logic. IMPORTANT Basing app behaviour on the value returned by backgroundTimeRemaining is the number two cause of background task problems on iOS. The system does not guarantee any background task execution time. It’s possible (albeit unlikely, as covered in the next point) that you’ll be unable to create a background task. And even if you do manage to create one, its expiry handler can be called at any time. beginBackgroundTask(expirationHandler:) can fail, returning UIBackgroundTaskInvalid, to indicate that you the system is unable to create a background task. While this was a real possibility when background tasks were first introduced, where some devices did not support multitasking, you’re unlikely to see this on modern systems. The background time ‘clock’ only starts to tick when the background task becomes effective. For example, if you start a background task while the app is in the foreground and then stay in the foreground, the background task remains dormant until your app moves to the background. This can help simplify your background task tracking logic. The amount of background execution time you get is a property of your app, not a property of the background tasks themselves. For example, starting two background task in a row won’t give you 60 seconds of background execution time. Notwithstanding the previous point, it can still make sense to create multiple background tasks, just to help with your tracking logic. For example, it’s common to create a background task for each job being done by your app, ending the task when the job is done. Do not create too many background tasks. How many is too many? It’s absolutely fine to create tens of background tasks but creating thousands is not a good idea. IMPORTANT iOS 11 introduced a hard limit on the number of background task assertions a process can have (currently about 1000, but the specific value may change in the future). If you see a crash report with the exception code 0xbada5e47, you’ve hit that limit. Note The practical limit that you’re most likely to see here is the time taken to call your expiry handlers. The watchdog has a strict limit (a few seconds) on the total amount of time taken to run background task expiry handlers. If you have thousands of handlers, you may well run into this limit. If you’re working in a context where you don’t have access to UIApplication (an app extension or on watchOS) you can achieve a similar effect using the performExpiringActivity(withReason:using:) method on ProcessInfo. If your app ‘leaks’ a background task, it may end up being killed by the watchdog. This results in a crash report with the exception code 0x8badf00d (“ate bad food”). IMPORTANT A leaked background task is not the only reason for an 0x8badf00d crash. You should look at the backtrace of the main thread to see if the main thread is stuck in your code, for example, in a synchronous networking request. If, however, the main thread is happily blocked in the run loop, a leaked background task should be your primary suspect. Prior to iOS 11 information about any outstanding background tasks would appear in the resulting crash report (look for the text BKProcessAssertion). This information is not included by iOS 11 and later, but you can find equivalent information in the system log. The system log is very noisy so it’s important that you give each of your background tasks an easy-to-find name. For more system log hints and tips, see Your Friend the System Log. iOS 13 introduced the Background Tasks framework. This supports two type of requests: The BGAppRefreshTaskRequest class subsumes UIKit’s older background app refresh functionality. The BGProcessingTaskRequest class lets you request extended background execution time, typically overnight. WWDC 2020 Session 10063 Background execution demystified is an excellent summary of iOS’s background execution model. Watch it, learn it, love it! For more background execution hints and tips, see Background Tasks Resources. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Revision History 2023-06-16 Added a link to my QRunInBackgroundAssertion post. 2022-06-08 Corrected a serious error in the discussion of BGProcessingTaskRequest. Replaced the basic system log info with a reference to Your Friend the System Log. Added a link to Background Tasks Resources. Made other minor editorial changes. 2021-02-27 Fixed the formatting. Added a reference to the Background Tasks framework and the Background execution demystified WWDC presentation. Minor editorial changes. 2019-01-20 Added a note about changes in the iOS 13 beta. Added a short discussion about beginning and ending background tasks on a secondary thread. 2018-02-28 Updated the task name discussion to account for iOS 11 changes. Added a section on how to debug ‘leaked’ background tasks. 2017-10-31 Added a note about iOS 11’s background task limit. 2017-09-12 Numerous updates to clarify various points. 2017-08-17 First posted.
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34k
Feb ’25
VOIP is not receiving calls
Hello, I am developing a calling service using CallKit and VOIP push. I have occasionally encountered a strange issue. The issue is that VOIP permanently fails to receive calls. I was previously informed that even if the device is blocked, it can receive calls again after 24 hours. Also, when I checked the device logic, it complied with the policy requirements set by Apple, including correctly calling CallKit's reportNewIncomingCall method. Once the issue occurs, no matter how many times I try, VOIP does not receive calls, and neither a device reboot nor checking the Device Console Log shows any logs related to CallKit or VOIP. I suspect this might be an issue with the VOIP token, and I believe that the only way to get a new one is to reinstall the app. Is that correct? Of course, after reinstalling, it works fine again, but this is very inconvenient. I don't think this is the right solution. Is there anyone who can share their insights on this issue? Thank you.
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224
Mar ’25
Location Permission Management for Parental Control Apps with Screen Time Authorization
Apple Feedback Ticket: FB16804936 Background We develop a parental control application called Adora Kids (https://apps.apple.com/us/app/adora-kids/id6443787669) that requires "Location Always" permission to function properly. Our app has Screen Time authorization and provides monitoring services for parents. Issue We are experiencing a recurring problem where child users receive the system notification "Adora accessed your location in the background" every few days. This frequently results in children disabling location permissions, which prevents our app from functioning as intended. Current Approach and Limitations We have explored using Content & Privacy Restrictions for Location Services as a potential solution, but have encountered two significant limitations: These restrictions cannot be accessed programmatically via the ManagedSettings framework (unlike AppStoreSettings and other restrictions). The current implementation is "all-or-nothing" - enabling location restrictions blocks permission changes for ALL apps on the device, preventing children from granting legitimate location access to other applications. Questions Is there a way to programmatically access and manage Content & Privacy Restrictions for Location Services through the ManagedSettings framework that we might have overlooked? Are there any recommended approaches for apps with Screen Time authorization to prevent users from changing specific permissions (particularly location) while still allowing them to manage permissions for other apps? Does Apple have plans to implement app-specific permission locking for apps with Screen Time authorization in future iOS releases? Are there any alternative approaches or workarounds that other developers have successfully implemented for this use case? Any guidance from the developer community or Apple engineers would be greatly appreciated. This is a critical functionality issue affecting the reliability of our parental control service. Thank you in advance for your assistance.
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3
313
Mar ’25