--- name: musickit description: "Integrate Apple Music playback, catalog search, and Now Playing metadata using MusicKit and MediaPlayer. Use when adding music search, Apple Music subscription flows, queue management, playback controls, remote command handling, or Now Playing info to iOS apps." --- # MusicKit Search the Apple Music catalog, manage playback with `ApplicationMusicPlayer`, check subscriptions, and publish Now Playing metadata via `MPNowPlayingInfoCenter` and `MPRemoteCommandCenter`. Targets Swift 6.3 / iOS 26+. ## Contents - [Setup](#setup) - [Authorization](#authorization) - [Catalog Search](#catalog-search) - [Subscription Checks](#subscription-checks) - [Playback with ApplicationMusicPlayer](#playback-with-applicationmusicplayer) - [Queue Management](#queue-management) - [Now Playing Info](#now-playing-info) - [Remote Command Center](#remote-command-center) - [Common Mistakes](#common-mistakes) - [Review Checklist](#review-checklist) - [References](#references) ## Setup ### Project Configuration 1. Enable the **MusicKit** capability in Xcode (adds the `com.apple.developer.musickit` entitlement) 2. Add `NSAppleMusicUsageDescription` to Info.plist explaining why the app accesses Apple Music 3. For background playback, add the `audio` background mode to `UIBackgroundModes` ### Imports ```swift import MusicKit // Catalog, auth, playback import MediaPlayer // MPRemoteCommandCenter, MPNowPlayingInfoCenter ``` ## Authorization Request permission before accessing the user's music data or playing Apple Music content. Authorization is a one-time prompt per app install. ```swift func requestMusicAccess() async -> MusicAuthorization.Status { let status = await MusicAuthorization.request() switch status { case .authorized: // Full access to MusicKit APIs break case .denied, .restricted: // Show guidance to enable in Settings break case .notDetermined: break @unknown default: break } return status } // Check current status without prompting let current = MusicAuthorization.currentStatus ``` ## Catalog Search Use `MusicCatalogSearchRequest` to search the Apple Music catalog. The user must have an Apple Music subscription for full catalog access. ```swift func searchCatalog(term: String) async throws -> MusicItemCollection { var request = MusicCatalogSearchRequest(term: term, types: [Song.self]) request.limit = 25 let response = try await request.response() return response.songs } ``` ### Displaying Results ```swift for song in songs { print("\(song.title) by \(song.artistName)") if let artwork = song.artwork { let url = artwork.url(width: 300, height: 300) // Load artwork from url } } ``` ## Subscription Checks Check whether the user has an active Apple Music subscription before offering playback features. ```swift func checkSubscription() async throws -> Bool { let subscription = try await MusicSubscription.current return subscription.canPlayCatalogContent } // Observe subscription changes func observeSubscription() async { for await subscription in MusicSubscription.subscriptionUpdates { if subscription.canPlayCatalogContent { // Enable full playback UI } else { // Show subscription offer } } } ``` ### Offering Apple Music Present the Apple Music subscription offer sheet when the user is not subscribed. ```swift import MusicKit import SwiftUI struct MusicOfferView: View { @State private var showOffer = false var body: some View { Button("Subscribe to Apple Music") { showOffer = true } .musicSubscriptionOffer(isPresented: $showOffer) } } ``` ## Playback with ApplicationMusicPlayer `ApplicationMusicPlayer` plays Apple Music content independently from the Music app. It does not affect the system player's state. ```swift let player = ApplicationMusicPlayer.shared func playSong(_ song: Song) async throws { player.queue = [song] try await player.play() } func pause() { player.pause() } func skipToNext() async throws { try await player.skipToNextEntry() } ``` ### Observing Playback State ```swift func observePlayback() { // player.state is an @Observable property let state = player.state switch state.playbackStatus { case .playing: break case .paused: break case .stopped, .interrupted, .seekingForward, .seekingBackward: break @unknown default: break } } ``` ## Queue Management Build and manipulate the playback queue using `ApplicationMusicPlayer.Queue`. ```swift // Initialize with multiple items func playAlbum(_ album: Album) async throws { player.queue = [album] try await player.play() } // Append songs to the existing queue func appendToQueue(_ songs: [Song]) async throws { try await player.queue.insert(songs, position: .tail) } // Insert song to play next func playNext(_ song: Song) async throws { try await player.queue.insert(song, position: .afterCurrentEntry) } ``` ## Now Playing Info Update `MPNowPlayingInfoCenter` so the Lock Screen, Control Center, and CarPlay display current track metadata. This is essential when playing custom audio (non-MusicKit sources). `ApplicationMusicPlayer` handles this automatically for Apple Music content. ```swift import MediaPlayer func updateNowPlaying(title: String, artist: String, duration: TimeInterval, elapsed: TimeInterval) { var info = [String: Any]() info[MPMediaItemPropertyTitle] = title info[MPMediaItemPropertyArtist] = artist info[MPMediaItemPropertyPlaybackDuration] = duration info[MPNowPlayingInfoPropertyElapsedPlaybackTime] = elapsed info[MPNowPlayingInfoPropertyPlaybackRate] = 1.0 info[MPNowPlayingInfoPropertyMediaType] = MPNowPlayingInfoMediaType.audio.rawValue MPNowPlayingInfoCenter.default().nowPlayingInfo = info } func clearNowPlaying() { MPNowPlayingInfoCenter.default().nowPlayingInfo = nil } ``` ### Adding Artwork ```swift func setArtwork(_ image: UIImage) { let artwork = MPMediaItemArtwork(boundsSize: image.size) { _ in image } var info = MPNowPlayingInfoCenter.default().nowPlayingInfo ?? [:] info[MPMediaItemPropertyArtwork] = artwork MPNowPlayingInfoCenter.default().nowPlayingInfo = info } ``` ## Remote Command Center Register handlers for `MPRemoteCommandCenter` to respond to Lock Screen controls, AirPods tap gestures, and CarPlay buttons. ```swift func setupRemoteCommands() { let center = MPRemoteCommandCenter.shared() center.playCommand.addTarget { _ in resumePlayback() return .success } center.pauseCommand.addTarget { _ in pausePlayback() return .success } center.nextTrackCommand.addTarget { _ in skipToNext() return .success } center.previousTrackCommand.addTarget { _ in skipToPrevious() return .success } // Disable commands you do not support center.seekForwardCommand.isEnabled = false center.seekBackwardCommand.isEnabled = false } ``` ### Scrubbing Support ```swift func enableScrubbing() { let center = MPRemoteCommandCenter.shared() center.changePlaybackPositionCommand.addTarget { event in guard let positionEvent = event as? MPChangePlaybackPositionCommandEvent else { return .commandFailed } seek(to: positionEvent.positionTime) return .success } } ``` ## Common Mistakes ### DON'T: Skip the MusicKit entitlement or usage description Without the MusicKit entitlement your app crashes at authorization. Without `NSAppleMusicUsageDescription`, App Review rejects the submission. ```swift // WRONG: No entitlement configured let status = await MusicAuthorization.request() // Crashes // CORRECT: Enable MusicKit capability in Xcode first, // then add NSAppleMusicUsageDescription to Info.plist let status = await MusicAuthorization.request() ``` ### DON'T: Forget to check subscription before playback Attempting to play catalog content without a subscription silently fails or throws. ```swift // WRONG func play(_ song: Song) async throws { player.queue = [song] try await player.play() // Fails if no subscription } // CORRECT func play(_ song: Song) async throws { let sub = try await MusicSubscription.current guard sub.canPlayCatalogContent else { showSubscriptionOffer() return } player.queue = [song] try await player.play() } ``` ### DON'T: Use SystemMusicPlayer when you mean ApplicationMusicPlayer `SystemMusicPlayer` controls the global Music app queue. Changes affect the user's Music app state. Use `ApplicationMusicPlayer` for app-scoped playback. ```swift // WRONG: Modifies the user's Music app queue let player = SystemMusicPlayer.shared // CORRECT: App-scoped playback let player = ApplicationMusicPlayer.shared ``` ### DON'T: Forget to update Now Playing info when track changes Stale metadata on the Lock Screen confuses users. Update Now Playing info every time the current track changes. ```swift // WRONG: Set once and forget updateNowPlaying(title: firstSong.title, ...) // CORRECT: Update on every track change func onTrackChanged(_ song: Song) { updateNowPlaying( title: song.title, artist: song.artistName, duration: song.duration ?? 0, elapsed: 0 ) } ``` ### DON'T: Register remote commands without handling them Registering a command but returning `.commandFailed` breaks Lock Screen controls. Disable commands you do not support instead. ```swift // WRONG center.skipForwardCommand.addTarget { _ in .commandFailed } // CORRECT center.skipForwardCommand.isEnabled = false ``` ## Review Checklist - [ ] MusicKit capability enabled in Xcode project - [ ] `NSAppleMusicUsageDescription` added to Info.plist - [ ] `MusicAuthorization.request()` called before any MusicKit access - [ ] Subscription checked before attempting catalog playback - [ ] `ApplicationMusicPlayer` used (not `SystemMusicPlayer`) for app-scoped playback - [ ] Background audio mode enabled if music plays in background - [ ] Now Playing info updated on every track change (for custom audio) - [ ] Remote command handlers return `.success` for supported commands - [ ] Unsupported remote commands disabled with `isEnabled = false` - [ ] Artwork provided in Now Playing info for Lock Screen display - [ ] Elapsed playback time updated periodically for scrubber accuracy - [ ] Subscription offer presented when user lacks Apple Music subscription ## References - Extended patterns (SwiftUI integration, genre browsing, playlist management): [references/musickit-patterns.md](references/musickit-patterns.md) - [MusicKit framework](https://sosumi.ai/documentation/musickit) - [MusicAuthorization](https://sosumi.ai/documentation/musickit/musicauthorization) - [ApplicationMusicPlayer](https://sosumi.ai/documentation/musickit/applicationmusicplayer) - [MusicCatalogSearchRequest](https://sosumi.ai/documentation/musickit/musiccatalogsearchrequest) - [MusicSubscription](https://sosumi.ai/documentation/musickit/musicsubscription) - [MPRemoteCommandCenter](https://sosumi.ai/documentation/mediaplayer/mpremotecommandcenter) - [MPNowPlayingInfoCenter](https://sosumi.ai/documentation/mediaplayer/mpnowplayinginfocenter) - [NSAppleMusicUsageDescription](https://sosumi.ai/documentation/bundleresources/information-property-list/nsapplemusicusagedescription)