I’m trying to build a CRUD app using SwiftData, @Query model and multidatepicker. The data from a multidatepicker is stored or persists in SwiftData as Set = []. My current dilemma is how to use SwiftData and @Query model Predicate to find all records on the current date. I can’t find any SwiftData documentation or examples @Query using Set = []. My CRUD app should retrieve all records for the current date. Unfortunately, I don’t know the correct @Query model syntax for Set = [].

I get crash reports which I can't reproduce when trying to present an SKStoreProductViewController : Fatal Exception: UIApplicationInvalidInterfaceOrientation Supported orientations has no common orientation with the application, and [SKStoreProductViewController shouldAutorotate] is returning YES No matter what app Deployment info orientation I try I can't get my SKStoreProductViewController shouldAutorotate property to return YES. It is always false. Does anyone knows why or how to get an SKStoreProductViewController to return shouldAutorotate YES?

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.

I've discovered a bug in the Phone app on iOS related to how long verdicts are displayed. When a call is identified by a third-party Caller ID app, long verdicts display correctly during the call (they auto-scroll) and in the call log (with an ellipsis at the end). However, on the call details screen, the text is strangely truncated - showing only the beginning of the string and the last word. For testing, I used this verdict: "Musclemen grow on trees. They can tense their muscles and look good in a mirror. So what? I'm interested in practical strength that's going to help me run, jump, twist, punch." I'll attach a screenshots demonstrating the problem:

ios構成プロファイルの制限のallowCloudPrivateRelayのプライベートリレーの制御とRelayペイロードの機能は関係がありますか？ それとも別々の機能でしょうか？ ↓ s there a relationship between the private relay control in the iOS configuration profile restriction allowCloudPrivateRelay and the functionality of the Relay payload? Or are they separate features?

It seems like find my mac is able to fetch the device location even if the device is in locked state. Why can’t other apps do the same.

We sell magazines through a third party app platform called Pocketmags and our website. The magazines have Print, Digital and Combo options available for purchase. Also, this third party app provides the platform to read the digital version of the magazines. Once a user buys a subscription on the website, he/she receives the email with the login information on PocketMags, where he registers his login details and can start reading his subscription. With us, the customer shares his billing/shipping address along with their email id while they make payment. Now we have our own app where through which we want to sell these magazines and have to integrate In-App purchase for selling these digital subscriptions. How do we send the 3rd party subscription access details on email to the user if they do in app purchase?

Platform and Version iOS Development Environment: Xcode 16.2.0, macOS 15.3 Run-time Configuration: iOS 18.3, 17.x Description of Problem We have started migrating some of the app’s core functionality over to App Intents. Our first release of App Intent support focused on two settings a user can modify on their Bose products, Audio Modes and Immersive Audio, giving users the ability to modify these settings via Siri and shortcuts. The implementation uses two separate shortcuts for each setting type, with each shortcut supporting a single phrase for Siri each: “Change my Bose mode to ” and “Change my Bose immersive audio to ”. Each shortcut uses their own App Intent, and each App Intent has support for optionally providing both a product and a setting when performing the intent. Failing to provide a device, which happens when the intent is performed via Siri, simply auto selects a currently connected Bose product. Failing to provide a setting, like in cases where a user says “Change my Bose ” without providing a setting will simply have Siri confirm the setting the user wants to change before changing the setting. We are using AppEntity to identify a Bose product for both App Intents. Because the App Intent for the Audio Modes setting has a larger number of supported values (up to 15 maximum), we are also using AppEntity to identify these settings. We are using AppEnum to identify available settings for the Immersive Audio App Intent, as only 3 static values are supported. Our original implementation of App Intent support had quite a few phrases supported for each shortcut. We had explicit support for direct synonyms of the verb “Change” in other phrases, supporting words like “Switch” and “Set”. We also had support for words that are like the word “Change”, but not directly related, like the word “Toggle” for instance. We also had support for phrases with or without the setting in each phrase. However, early on we had a lot of trouble with phrase detection with Siri. Siri had a hard time identifying what shortcut was being requested, as well as not being able to identify what settings the user was providing for the setting parameter of each App Intent. While researching potential fixes for this issue, we found a response to a thread in the Apple forums (https://developer.apple.com/forums/thread/759909) that seemed to indicate that Siri phrase recognition was very much an aggregate process. With the total number of phrases supported combined with the available settings for each phrase further compounding the total number of phrases Siri needs to learn to recognize for each shortcut. So, to hopefully improve Siri phrase detection, we added logic to limit the amount of Audio Mode settings supported based on what Audio Modes the user had setup on their Bose products. But, more importantly, we limited the number of explicit phrases supported for each shortcut to just a single phrase. In our testing, not only did this improve phrase recognition, but support for synonyms like “Set” or “Switch” seemed to implicitly still be recognized by Siri. The issues we ran into with Siri phrase detection above has us a bit concerned about scaling App Intent support to other settings and features for our products in the future. Our app supports the ability to modify a large number of settings on their Bose products, with support constantly expanding to new products as they are released. Our roadmap for App Intent support was initially very ambitious, supporting much more than just the two settings mentioned above. But our initial experience with App Intents has us tapering our expectations a little bit as far as how much can be supported in total for App Intents. One thing we also noticed is less than optimal display of default shortcuts in the Shortcuts app. The default shortcuts appeared like so, with shortcuts displayed based on available settings fro each shortcut: However, we could not find a way to indicate to users that one particular section pertained specifically to the Audio Mode setting and the other to the Immersive Audio setting. The only information the user has to make this determination for themselves is the available settings (or shortcuts) for each. This may not be immediately clear to a new customer who might be using one of our products for the first time. This display of default shortcuts in the Shortcuts app has us wondering if our shortcuts implementation is what is intended as far as support for the Shortcuts app is concerned. We did survey default shortcuts displayed by other third-party applications and they mostly dealt with navigation with a single section containing default options clearly indicating where the user can navigate with a shortcut. We couldn’t find an example of an application supporting the ability to change different setting types, with each setting type having their own available values for each. So, to summarize the questions we have concerning App Intent support: What can we do with our App Intents and Shortcuts implementation to guarantee optimal performance with Siri? What is an ideal number of phrases to support for each Shortcut. What limitations should we be placing as far as the total number of available settings for each Shortcut. Are there phrases that might work better than others for what we’re trying to achieve with App Intent support? i.e. Is “Change my Bose mode” or “Change my Bose immersive audio” a good phrase to use for this kind of functionality? Or should we be using different verbs or wording? Assuming optimal support of each Shortcut above. What is a reasonable expectation as far as how many different supported shortcuts we can scale to support at the same time. One issue we ran into early on was Siri confusing one shortcut with the other and triggering the wrong App Intent at times. While this was ultimately resolved, this outcome seems much more likely the greater the number of individual shortcuts supported. Are there any recommendations on how to display these App Intents to customers as far as default shortcuts in the Shortcuts app is concerned? Is what we currently display for default shortcuts in the Shortcuts app what was initially intended for third party support for App Intents? If what we are currently displaying is expected, would it be possible to support the ability to provide additional context to each section of default shortcuts displayed? We would like to indicate to the user that one set of shortcuts pertains to the Audio Modes settings, and the other to Immersive Audio. Something along the lines of a section header like some of the first-party apps use. Are there any recommendations or tips for supporting App Intents, particularly phrases for Siri, in other languages?

I'm currently integrating Apple Pay with my payment provider, and I'm encountering a signature validation error during the payment flow. Here's the setup: I’ve verified that my Merchant Certificate is valid, and I'm able to initialize the Apple Pay session without any issues. Also this curl works fine The Payment Processing Certificate was created by my PSP. PSP claims that the payment token signature is invalid during the transaction phase, which prevents payment completion. The parsed signature starts like this 0:d=0 hl=2 l=inf cons: SEQUENCE 2:d=1 hl=2 l= 9 prim: OBJECT :pkcs7-signedData 13:d=1 hl=2 l=inf cons: cont [ 0 ] 15:d=2 hl=2 l=inf cons: SEQUENCE 17:d=3 hl=2 l= 1 prim: INTEGER :01 20:d=3 hl=2 l= 13 cons: SET 22:d=4 hl=2 l= 11 cons: SEQUENCE 24:d=5 hl=2 l= 9 prim: OBJECT :sha256 35:d=3 hl=2 l=inf cons: SEQUENCE 37:d=4 hl=2 l= 9 prim: OBJECT :pkcs7-data 48:d=4 hl=2 l= 0 prim: EOC 50:d=3 hl=2 l=inf cons: cont [ 0 ] 52:d=4 hl=4 l= 995 cons: SEQUENCE 56:d=5 hl=4 l= 904 cons: SEQUENCE 60:d=6 hl=2 l= 3 cons: cont [ 0 ] 62:d=7 hl=2 l= 1 prim: INTEGER :02 65:d=6 hl=2 l= 8 prim: INTEGER :16634C8B0E305717 75:d=6 hl=2 l= 10 cons: SEQUENCE 77:d=7 hl=2 l= 8 prim: OBJECT :ecdsa-with-SHA256 87:d=6 hl=2 l= 122 cons: SEQUENCE 89:d=7 hl=2 l= 46 cons: SET 91:d=8 hl=2 l= 44 cons: SEQUENCE 93:d=9 hl=2 l= 3 prim: OBJECT :commonName 98:d=9 hl=2 l= 37 prim: UTF8STRING :Apple Application Integration CA - G3 I'm looking for guidance on what could be causing this signature failure. Does anyone know what else I can check regarding the merchant or payment processing certificates, private keys, or key usage that might cause Apple Pay signature validation to fail, even if the session initializes successfully? Domains are also verified. Any help or suggestions would be greatly appreciated.

I'm curious, why DynamicOptionsProvider is available on watchOS? Is there any way to present options to the user? For example in Emoji Rangers project: struct EmojiRangerSelection: AppIntent, WidgetConfigurationIntent { static let intentClassName = "EmojiRangerSelectionIntent" static var title: LocalizedStringResource = "Emoji Ranger Selection" static var description = IntentDescription("Select Hero") @Parameter(title: "Selected Hero", default: EmojiRanger.cake, optionsProvider: EmojiRangerOptionsProvider()) var hero: EmojiRanger? struct EmojiRangerOptionsProvider: DynamicOptionsProvider { func results() async throws -> [EmojiRanger] { EmojiRanger.allHeros } } func perform() async throws -> some IntentResult { return .result() } } On watchOS we usually use recommendations() to give the user predefined choice of configured widgets. Meanwhile in AppIntentProvider recommendations are empty: struct AppIntentProvider: AppIntentTimelineProvider { ... func recommendations() -> [AppIntentRecommendation<EmojiRangerSelection>] { [] } } Does it imply that there's a way to use DynamicOptionsProvider on watchOS somehow? BTW, WidgetConfiguration.promptsForUserConfiguration() is one of the methods that are not available on watchOS. And also, the Emoji Ranger project doesn't show widgets (complications) on watchOS out of the box.

I am facing an issue with Apple Pay js while doing the integration we are using reference https://applepaydemo.apple.com/apple-pay-js-api In this I can generate the merchantSession correctly But when I pass that merchantSession in session.completeMerchantValidation(merchantValidation) as per documentation It is getting failed and also no appropriate error is being shown in the console

Hi Guys, I am having an issue verifying a card when it is pending verification in the Apple Watch Wallet App and the iPhone Wallet. When the user verifies the card in the wallets, they are redirected to verification in my APP. However, the problem is that I don't know which application is calling, whether it is the Apple Watch or the iPhone, because the URL sends me the same serialNumber from the PKPASS. It is impossible to know if the user wants to verify and activate the card on the watch or the iPhone. Because I only receive the following information in the URL: myapp://app-url? passTypeldentifier=paymentpass.com.apple&action =verify&serialNumber=***** The serialNumber is the same from the iPhone Wallet and the Watch Wallet. func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool { let source = options[.sourceApplication] I try to retrieve the source, but it comes back null. It would be the only way to know the originating App. Can someone help me solve this problem?

Hi Team, We’re encountering a device-specific issue with our SMS Message Filter extension. The extension works as expected on an iPhone 11 running iOS 16.6, but it does not trigger on an iPhone 12 Pro running iOS 16.7. Key Observations: The extension is implemented using ILMessageFilterExtension and calls messageFilterOffline(appGroupIdentifier:for:) from our shared library. The App Group is properly configured and accessible across the app and extension. The extension is enabled under Settings &gt; Messages &gt; Unknown &amp; Spam. There are no crashes or error logs reported on the affected device. The issue is consistently reproducible — it works on one device but not the other. We’re wondering if this could be a regression or a device-specific behavior change introduced in iOS 16.7. Has anyone encountered similar inconsistencies in Message Filter extensions across different iOS versions or device models? Any guidance or suggestions would be greatly appreciated. Thanks in advance!

If I run an app with a message filter extension, it's triggered for all the prepaid unknown numbers and its not triggered for all the unknown postpaid numbers. Any idea, how to trigger for postpaid unknown numbers?.

We are experiencing an Unknown Error (error code 0) when testing purchases in the Apple Sandbox environment. The error does not occur every time, but it fails with an Unknown Error in approximately 8 out of 20 attempts. Due to this issue, our app is failing to pass Apple’s review. Issue Details This issue only occurs in the Apple Sandbox environment. After attempting a purchase, the Apple payment API returns SKPaymentTransaction Unknown Error. Returned error code: SKErrorUnknown (error.code 0). This problem is preventing us from conducting proper payment tests and getting approval from Apple. Would it be possible to receive support or any solutions for this issue?

https://developer.apple.com/documentation/apple_pay_on_the_web/applepaypaymentrequest/3955945-multitokencontexts According to this document, I know that I can initialize a multiTokenContexts when initializing ApplePayPaymentRequest. But I am now facing a tricky problem. If the user's order does not require multiTokenContexts, then I will not initialize this field when I first make ApplePayPaymentRequest. When the user is in the payment process, I may update multiTokenContexts. But this time, the update is not allowed, ApplePay will be cancelled and the payment will be closed. For example, if the user's address in Apple Pay is different, I need to update multiTokenContexts to support the payment of goods to multiple merchants, which will generate an update of multiTokenContexts. MultiTokenContexts can be updated in the onshippingcontactselected method. https://developer.apple.com/documentation/apple_pay_on_the_web/applepaysession/1778009-onshippingcontactselected My question is that from the beginning, there was no multiTokenContexts to update multiTokenContexts in onshippingcontactselected, which would cause the user to close the payment and need to manually click to pay again. This user experience is not very friendly. Is there a better way for me to go from no multiTokenContexts to multiTokenContexts without interrupting the user's payment process?

Howdy, I'm trying to figure out how to replicate the following behavior for our app: The system is able to ascertain that the Mac equivalent of some iOS app is installed locally, and it prevents notifications from being mirrored. However, I am unable to determine how this association is inferred. When I check our iOS app under this prefpane, the switch remains enabled and toggleable—we'd like to act like Slack here. My initial assumption is that an app group containing both the Mac and iOS apps can be used to create the association; however, I would like to confirm that this is indeed the case before doing so. I'm not terribly confident about this. Details: The bundle identifiers of both apps do not match. This also applies to Slack; its iOS app is com.tinyspeck.chatlyio while its Mac app is com.tinyspeck.slackmacgap. In our case, the iOS app's identifier is like com.company.app while the Mac app's identifier is com.company.app.desktop. Both apps are signed with certificates that have matching team identifiers. The com.apple.developer.team-identifier entitlement is present on the Mac app. The Mac app shares a keychain access group with the iOS app. The Mac app is not sandboxed. The Mac app is an Electron app. The Mac app does not use APNs. It sends notifications "locally". I currently only have the iOS app installed on my iPhone via TestFlight, if that matters. Notification mirroring does work, but we'd like to forcibly disable this by associating the apps together. To my knowledge, the iOS app makes use of both a UNNotificationServiceExtension and a UNNotificationContentExtension. The iOS app currently doesn't have an assigned category (at least in Xcode). The Mac app is currently miscategorized as a developer tool (LSApplicationCategoryType = "public.app-category.developer-tools";), but that should be fixed. (Redacted) bundle information for the Mac app: CFBundleDisplayName = App; CFBundleExecutable = "App Desktop"; CFBundleName = App; Note that our CFBundleExecutable differs from the bundle's display name/name because we're currently migrating our users to a new version of the app that they'd likely want to live alongside the new one. The filename of the bundle itself is, similarly, App Desktop.app. For the iOS app, to my knowledge, the CFBundleName and CFBundleDisplayName are App.

I noticed a very weird behavior for refunds. When a user refunds an up-front paid app, they still have access to the app. How can I detect such a case and block access to the app? In general, I think it should be handled by Apple, but for some reason, they don't do it.

Greetings, I recently submitted a request for the Location Push Service Extension Entitlement. Does anybody have insight into how long I would have to wait until Apple responds? Thanks

The NSMetadataUbiquitousItemDownloadingStatusKey indicates the status of a ubiquitous (iCloud Drive) file. A key value of NSMetadataUbiquitousItemDownloadingStatusDownloaded is defined as indicating there is a local version of this file available. The most current version will get downloaded as soon as possible . However this no longer occurs since iOS 18.4. A ubiquitous file may remain in the NSMetadataUbiquitousItemDownloadingStatusDownloaded state for an indefinite period. There is a workaround: call [NSFileManager startDownloadingUbiquitousItemAtURL: error:] however this shouldn't be necessary, and introduces delays over the previous behaviour. Has anyone else seen this behaviour? Is this a permanent change? FB17662379