Files
letro-ios/NSE/Sources/NotificationServiceExtension.swift

246 lines
12 KiB
Swift

//
// Copyright 2025 Element Creations Ltd.
// Copyright 2022-2025 New Vector Ltd.
//
// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
// Please see LICENSE files in the repository root for full details.
//
import Combine
import MatrixRustSDK
import UserNotifications
// The lifecycle of the NSE looks something like the following:
// 1) App receives notification
// 2) System creates an instance of the extension class
// and calls `didReceive` in the background
// 3) Extension processes messages / displays whatever
// notifications it needs to
// 4) Extension notifies its work is complete by calling
// the contentHandler
// 5) If the extension takes too long to perform its work
// (more than 30s), it will be notified and immediately
// terminated
//
// Note that the NSE does *not* always spawn a new process to
// handle a new notification and will also try and process notifications
// in parallel. `didReceive` could be called twice for the same process,
// but it will always be called on different threads. It may or may not be
// called on the same instance of `NotificationService` as a previous
// notification.
class NotificationServiceExtension: UNNotificationServiceExtension {
static let receivedWhileOfflineNotificationID = "io.element.elementx.receivedWhileOfflineNotification"
private static var targetConfiguration: Target.ConfigurationResult?
private static var hasHandledFirstNotificationSinceBoot = false
private static let firstNotificationThreshold: TimeInterval = 15 * 60
private let settings: CommonSettingsProtocol = AppSettings()
private let appHooks: AppHooks
private var notificationHandler: NotificationHandler?
private let keychainController = KeychainController(service: .sessions,
accessGroup: InfoPlistReader.main.keychainAccessGroupIdentifier)
private var cancellables: Set<AnyCancellable> = []
/// We can make the whole NSE a MainActor after https://github.com/swiftlang/swift-evolution/blob/main/proposals/0371-isolated-synchronous-deinit.md
/// otherwise we wouldn't be able to log the tag in the deinit.
deinit {
ExtensionLogger.logMemory(with: tag)
MXLog.info("\(tag) deinit")
}
override init() {
appHooks = AppHooks()
appHooks.setUp()
// If the device is still locked then we can't write to the app group container and
// the target configuration will fail. We could call exit(0) here, however with the
// notification filtering entitlement that results in the notification being discarded
// so we need to wait for the delegate method to be called and bail out there instead.
if !BootDetectionManager.isDeviceLockedAfterReboot(containerURL: URL.appGroupContainerDirectory),
Self.targetConfiguration == nil {
Self.targetConfiguration = Target.nse.configure(logLevel: settings.logLevel,
traceLogPacks: settings.traceLogPacks,
sentryURL: nil,
rageshakeURL: settings.bugReportRageshakeURL,
appHooks: appHooks)
}
super.init()
}
override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
Task { await handle(request, withContentHandler: contentHandler) }
}
private func handle(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) async {
// If we skipped configuring the target it means we can't write to the app group, so we're unlikely to
// be able to create a session (and even if we could, we would be missing the lightweightTokioRuntime).
// Additionally, APNs servers only store the most recent notification when the device is powered off.
// So lets a) skip processing the notification and b) deliver a special "offline" notification as a workaround.
guard Self.targetConfiguration != nil else {
// MXLog isn't configured:
// swiftlint:disable:next print_deprecation
print("Device is locked after reboot.")
if Self.hasHandledFirstNotificationSinceBoot {
return contentHandler(request.content)
} else {
Self.hasHandledFirstNotificationSinceBoot = true
deliverReceivedWhileOfflineNotification(for: request)
return contentHandler(.init())
}
}
guard !shouldDeliverReceivedWhileOfflineNotification() else {
// Don't log until the app hooks have been run:
// swiftlint:disable:next print_deprecation
print("Device is unlocked but may have missed notifications while offline.")
deliverReceivedWhileOfflineNotification(for: request)
return contentHandler(.init())
}
guard let roomID = request.content.roomID else {
// Don't log until the app hooks have been run:
// swiftlint:disable:next print_deprecation
print("Missing roomID, bailing out.")
return contentHandler(request.content)
}
guard let eventID = request.content.eventID else {
// Don't log until the app hooks have been run:
// swiftlint:disable:next print_deprecation
print("Missing eventID, bailing out.")
return contentHandler(request.content)
}
guard let clientID = request.content.pusherNotificationClientIdentifier else {
// Don't log until the app hooks have been run:
// swiftlint:disable:next print_deprecation
print("Missing clientID, bailing out.")
return contentHandler(request.content)
}
guard let credentials = keychainController.restorationTokens().first(where: { $0.restorationToken.pusherNotificationClientIdentifier == clientID }) else {
// Don't log until the app hooks have been run:
// swiftlint:disable:next print_deprecation
print("Credentials not found, bailing out.")
return contentHandler(request.content)
}
let homeserverURL = credentials.restorationToken.session.homeserverUrl
await appHooks.remoteSettingsHook.loadCache(forHomeserver: homeserverURL, applyingTo: settings)
guard let mutableContent = request.content.mutableCopy() as? UNMutableNotificationContent else {
return contentHandler(request.content)
}
MXLog.info("\(tag) #########################################")
ExtensionLogger.logMemory(with: tag)
MXLog.info("\(tag) Received payload: \(request.content.userInfo)")
do {
let userSession = try await NSEUserSession(credentials: credentials,
roomID: roomID,
clientSessionDelegate: keychainController,
appHooks: appHooks,
appSettings: settings)
notificationHandler = NotificationHandler(userSession: userSession,
settings: settings,
contentHandler: contentHandler,
notificationContent: mutableContent,
tag: tag)
ExtensionLogger.logMemory(with: tag)
MXLog.info("\(tag) Configured user session")
await notificationHandler?.processEvent(eventID, roomID: roomID)
} catch {
MXLog.error("Failed creating user session with error: \(error)")
}
}
override func serviceExtensionTimeWillExpire() {
notificationHandler?.handleTimeExpiration()
}
// MARK: - Boot handling
/// The APNs servers only store the most recent notification when delivery fails. So when the user first boots
/// their phone we need to use some approximations to decide whether or not the first notification may potentially
/// represent more than one message. When that appears possible we replace the notification's content with the special
/// "received while offline" notification as a more prominent prompt for to the user to open the app and check all their chats.
///
/// Note that this only handles the first-boot case. When the SDK is able to compute the unread count, we should start to use the NSE,
/// remote-notifications (content-available) and background app refreshes to fetch and deliver our notifications as a more robust solution.
private func shouldDeliverReceivedWhileOfflineNotification() -> Bool {
if Self.hasHandledFirstNotificationSinceBoot {
// If we've already handled the first notification in this process there's no need to continue.
return false
}
Self.hasHandledFirstNotificationSinceBoot = true
guard let currentBootTime = BootDetectionManager.systemBootTime() else {
// There's not much we can do if the boot time is unknown, so don't show the offline notification.
return false
}
guard let lastKnownBootTime = settings.lastNotificationBootTime else {
// Assume a missing boot time indicates a fresh installation
// So store the current boot time but let the notification through.
settings.lastNotificationBootTime = currentBootTime
return false
}
if abs(lastKnownBootTime - currentBootTime) < 1 {
return false
}
// This is the first notification since boot, store the boot time.
settings.lastNotificationBootTime = currentBootTime
// At this point it becomes a trade-off. Once the device has been powered on for a long enough amount
// of time it is a reasonable assumption that the device has now connected to a network and that any
// notification is actually new rather than having been sent whilst the device was powered off.
//
// Note: We could actually solve this by having Sygnal add a timestamp to the notification payload 🤔
if Date.now.timeIntervalSince(Date(timeIntervalSince1970: currentBootTime)) > Self.firstNotificationThreshold {
return false
} else {
return true
}
}
/// Delivers a generic notification informing the user that they have one or more new messages.
///
/// Note: it is safe to call this method multiple times as it simply replaces any existing instance of the notification
/// with a fresh copy, meaning it won't queue multiple copies but will still re-play the notification sound.
private func deliverReceivedWhileOfflineNotification(for originalRequest: UNNotificationRequest) {
// This is intended to be called before the app hooks have been run, so don't log:
// swiftlint:disable:next print_deprecation
print("Delivering the 'received while offline' notification.")
let content = UNMutableNotificationContent()
content.body = L10n.notificationReceivedWhileOfflineIos
content.badge = originalRequest.content.unreadCount as NSNumber?
content.sound = .init(named: settings.notificationSoundName.publisher.value)
let request = UNNotificationRequest(identifier: Self.receivedWhileOfflineNotificationID, content: content, trigger: nil)
UNUserNotificationCenter.current().add(request)
}
// MARK: - Logging
private var tag: String {
"[NSE][\(Unmanaged.passUnretained(self).toOpaque())][\(Unmanaged.passUnretained(Thread.current).toOpaque())][\(ProcessInfo.processInfo.processIdentifier)]"
}
}