Tusker/NotificationExtension/NotificationService.swift

353 lines
14 KiB
Swift

//
// NotificationService.swift
// NotificationExtension
//
// Created by Shadowfacts on 4/9/24.
// Copyright © 2024 Shadowfacts. All rights reserved.
//
import UserNotifications
import UserAccounts
import PushNotifications
import CryptoKit
import OSLog
import Pachyderm
import Intents
import HTMLStreamer
import WebURL
private let logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "NotificationService")
class NotificationService: UNNotificationServiceExtension {
private static let textConverter = TextConverter(configuration: .init(insertNewlines: false), callbacks: HTMLCallbacks.self)
private var pendingRequest: (UNMutableNotificationContent, (UNNotificationContent) -> Void, Task<Void, Never>)?
override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
guard let mutableContent = request.content.mutableCopy() as? UNMutableNotificationContent else {
logger.error("Couldn't get mutable content")
contentHandler(request.content)
return
}
guard request.content.userInfo["v"] as? Int == 1,
let accountID = request.content.userInfo["ctx"] as? String,
let account = UserAccountsManager.shared.getAccount(id: accountID),
let subscription = getSubscription(account: account),
let encryptedBody = (request.content.userInfo["data"] as? String).flatMap({ Data(base64Encoded: $0) }),
let salt = (request.content.userInfo["salt"] as? String).flatMap(decodeBase64URL(_:)),
let serverPublicKeyData = (request.content.userInfo["pk"] as? String).flatMap(decodeBase64URL(_:)) else {
logger.error("Missing info from push notification")
contentHandler(request.content)
return
}
guard let body = decryptNotification(subscription: subscription, serverPublicKeyData: serverPublicKeyData, salt: salt, encryptedBody: encryptedBody) else {
contentHandler(request.content)
return
}
let withoutPadding = body.dropFirst(2)
let notification: PushNotification
do {
notification = try JSONDecoder().decode(PushNotification.self, from: withoutPadding)
} catch {
logger.error("Unable to decode push payload: \(String(describing: error))")
contentHandler(request.content)
return
}
mutableContent.title = notification.title
mutableContent.body = notification.body
let task = Task {
await updateNotificationContent(mutableContent, account: account, push: notification)
if !Task.isCancelled {
contentHandler(pendingRequest?.0 ?? mutableContent)
pendingRequest = nil
}
}
pendingRequest = (mutableContent, contentHandler, task)
}
override func serviceExtensionTimeWillExpire() {
if let pendingRequest {
logger.debug("Expiring with pending request")
pendingRequest.2.cancel()
pendingRequest.1(pendingRequest.0)
self.pendingRequest = nil
} else {
logger.debug("Expiring without pending request")
}
}
private func updateNotificationContent(_ content: UNMutableNotificationContent, account: UserAccountInfo, push: PushNotification) async {
let client = Client(baseURL: account.instanceURL, accessToken: account.accessToken)
let notification: Pachyderm.Notification
do {
notification = try await client.run(Client.getNotification(id: push.notificationID)).0
} catch {
logger.error("Error fetching notification: \(String(describing: error))")
return
}
let kindStr: String?
switch notification.kind {
case .reblog:
kindStr = "🔁 Reblogged"
case .favourite:
kindStr = "⭐️ Favorited"
case .follow:
kindStr = "👤 Followed by @\(notification.account.acct)"
case .followRequest:
kindStr = "👤 Asked to follow by @\(notification.account.acct)"
case .poll:
kindStr = "📊 Poll finished"
case .update:
kindStr = "✏️ Edited"
default:
kindStr = nil
}
let notificationContent: String?
if let status = notification.status {
notificationContent = NotificationService.textConverter.convert(html: status.content)
} else if notification.kind == .follow || notification.kind == .followRequest {
notificationContent = nil
} else {
notificationContent = push.body
}
content.body = [kindStr, notificationContent].compactMap { $0 }.joined(separator: "\n")
let attachmentDataTask: Task<URL?, Never>?
// We deliberately don't include attachments for other types of notifications that have statuses (favs, etc.)
// because we risk just fetching the same thing a bunch of times for many senders.
if notification.kind == .mention || notification.kind == .status || notification.kind == .update,
let attachment = notification.status?.attachments.first {
let url = attachment.previewURL ?? attachment.url
attachmentDataTask = Task {
do {
let data = try await URLSession.shared.data(from: url).0
let localAttachmentURL = FileManager.default.temporaryDirectory.appendingPathComponent("attachment_\(attachment.id)").appendingPathExtension(url.pathExtension)
try data.write(to: localAttachmentURL)
return localAttachmentURL
} catch {
logger.error("Error setting notification attachments: \(String(describing: error))")
return nil
}
}
} else {
attachmentDataTask = nil
}
let conversationIdentifier: String?
if let status = notification.status {
if let context = status.pleromaExtras?.context {
conversationIdentifier = "context:\(context)"
} else if [Notification.Kind.reblog, .favourite, .poll, .update].contains(notification.kind) {
conversationIdentifier = "status:\(status.id)"
} else {
conversationIdentifier = nil
}
} else {
conversationIdentifier = nil
}
let account: Account?
switch notification.kind {
case .mention, .status:
account = notification.status?.account
default:
account = notification.account
}
let sender: INPerson?
if let account {
let handle = INPersonHandle(value: "@\(account.acct)", type: .unknown)
let image: INImage?
if let avatar = account.avatar,
let (data, resp) = try? await URLSession.shared.data(from: avatar),
let code = (resp as? HTTPURLResponse)?.statusCode,
(200...299).contains(code) {
image = INImage(imageData: data)
} else {
image = nil
}
sender = INPerson(
personHandle: handle,
nameComponents: nil,
displayName: account.displayName,
image: image,
contactIdentifier: nil,
customIdentifier: account.id
)
} else {
sender = nil
}
let intent = INSendMessageIntent(
recipients: nil,
outgoingMessageType: .outgoingMessageText,
content: notificationContent,
speakableGroupName: nil,
conversationIdentifier: conversationIdentifier,
serviceName: nil,
sender: sender,
attachments: nil
)
let interaction = INInteraction(intent: intent, response: nil)
interaction.direction = .incoming
do {
try await interaction.donate()
} catch {
logger.error("Error donating interaction: \(String(describing: error))")
return
}
let updatedContent: UNMutableNotificationContent
do {
let newContent = try content.updating(from: intent)
if let newMutableContent = newContent.mutableCopy() as? UNMutableNotificationContent {
pendingRequest?.0 = newMutableContent
updatedContent = newMutableContent
} else {
updatedContent = content
}
} catch {
logger.error("Error updating notification from intent: \(String(describing: error))")
updatedContent = content
}
if let localAttachmentURL = await attachmentDataTask?.value,
let attachment = try? UNNotificationAttachment(identifier: localAttachmentURL.lastPathComponent, url: localAttachmentURL) {
updatedContent.attachments = [
attachment
]
}
}
private func getSubscription(account: UserAccountInfo) -> PushNotifications.PushSubscription? {
DispatchQueue.main.sync {
// this is necessary because of a swift bug: https://github.com/apple/swift/pull/72507
MainActor.runUnsafely {
PushManager.shared.pushSubscription(account: account)
}
}
}
private func decryptNotification(subscription: PushNotifications.PushSubscription, serverPublicKeyData: Data, salt: Data, encryptedBody: Data) -> Data? {
// See https://github.com/ClearlyClaire/webpush/blob/f14a4d52e201128b1b00245d11b6de80d6cfdcd9/lib/webpush/encryption.rb
var context = Data()
context.append(0)
let clientPublicKey = subscription.secretKey.publicKey.x963Representation
let clientPublicKeyLength = UInt16(clientPublicKey.count)
context.append(UInt8((clientPublicKeyLength >> 8) & 0xFF))
context.append(UInt8(clientPublicKeyLength & 0xFF))
context.append(clientPublicKey)
let serverPublicKeyLength = UInt16(serverPublicKeyData.count)
context.append(UInt8((serverPublicKeyLength >> 8) & 0xFF))
context.append(UInt8(serverPublicKeyLength & 0xFF))
context.append(serverPublicKeyData)
func info(encoding: String) -> Data {
var info = Data("Content-Encoding: \(encoding)\0P-256".utf8)
info.append(context)
return info
}
let sharedSecret: SharedSecret
do {
let serverPublicKey = try P256.KeyAgreement.PublicKey(x963Representation: serverPublicKeyData)
sharedSecret = try subscription.secretKey.sharedSecretFromKeyAgreement(with: serverPublicKey)
} catch {
logger.error("Error getting shared secret: \(String(describing: error))")
return nil
}
let sharedInfo = Data("Content-Encoding: auth\0".utf8)
let pseudoRandomKey = sharedSecret.hkdfDerivedSymmetricKey(using: SHA256.self, salt: subscription.authSecret, sharedInfo: sharedInfo, outputByteCount: 32)
let contentEncryptionKeyInfo = info(encoding: "aesgcm")
let contentEncryptionKey = HKDF<SHA256>.deriveKey(inputKeyMaterial: pseudoRandomKey, salt: salt, info: contentEncryptionKeyInfo, outputByteCount: 16)
let nonceInfo = info(encoding: "nonce")
let nonce = HKDF<SHA256>.deriveKey(inputKeyMaterial: pseudoRandomKey, salt: salt, info: nonceInfo, outputByteCount: 12)
let nonceAndEncryptedBody = nonce.withUnsafeBytes { noncePtr in
var data = Data(buffer: noncePtr.bindMemory(to: UInt8.self))
data.append(encryptedBody)
return data
}
do {
let sealedBox = try AES.GCM.SealedBox(combined: nonceAndEncryptedBody)
let decrypted = try AES.GCM.open(sealedBox, using: contentEncryptionKey)
return decrypted
} catch {
logger.error("Error decrypting push: \(String(describing: error))")
return nil
}
}
}
extension MainActor {
@_unavailableFromAsync
@available(macOS, obsoleted: 14.0)
@available(iOS, obsoleted: 17.0)
@available(watchOS, obsoleted: 10.0)
@available(tvOS, obsoleted: 17.0)
static func runUnsafely<T>(_ body: @MainActor () throws -> T) rethrows -> T {
if #available(macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0, *) {
return try MainActor.assumeIsolated(body)
}
dispatchPrecondition(condition: .onQueue(.main))
return try withoutActuallyEscaping(body) { fn in
try unsafeBitCast(fn, to: (() throws -> T).self)()
}
}
}
private func decodeBase64URL(_ s: String) -> Data? {
var str = s.replacingOccurrences(of: "-", with: "+").replacingOccurrences(of: "_", with: "/")
if str.count % 4 != 0 {
str.append(String(repeating: "=", count: 4 - str.count % 4))
}
return Data(base64Encoded: str)
}
// copied from HTMLConverter.Callbacks, blergh
private struct HTMLCallbacks: HTMLConversionCallbacks {
static func makeURL(string: String) -> URL? {
// Converting WebURL to URL is a small but non-trivial expense (since it works by
// serializing the WebURL as a string and then having Foundation parse it again),
// so, if available, use the system parser which doesn't require another round trip.
if #available(iOS 16.0, macOS 13.0, *),
let url = try? URL.ParseStrategy().parse(string) {
url
} else if let web = WebURL(string),
let url = URL(web) {
url
} else {
URL(string: string)
}
}
static func elementAction(name: String, attributes: [Attribute]) -> ElementAction {
guard name == "span" else {
return .default
}
let clazz = attributes.attributeValue(for: "class")
if clazz == "invisible" {
return .skip
} else if clazz == "ellipsis" {
return .append("")
} else {
return .default
}
}
}