UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) {
    granted, error in
    if granted {
        // 用户允许进行通知
    }
}

// 向 APNs 请求 token：
UIApplication.shared.registerForRemoteNotifications()

// AppDelegate.swift
 func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    let tokenString = deviceToken.hexString
    print("Get Push token: \(tokenString)")
}

extension Data {
    var hexString: String {
        return withUnsafeBytes {(bytes: UnsafePointer<UInt8>) -> String in
            let buffer = UnsafeBufferPointer(start: bytes, count: count)
            return buffer.map {String(format: "%02hhx", $0)}.reduce("", { $0 + $1 })
        }
    }
}

UNUserNotificationCenter.current().getNotificationSettings {
    settings in 
    print(settings.authorizationStatus) // .authorized | .denied | .notDetermined
    print(settings.badgeSetting) // .enabled | .disabled | .notSupported
    // etc...
}

// 1. 创建通知内容
let content = UNMutableNotificationContent()
content.title = "Time Interval Notification"
content.body = "My first notification"

// 2. 创建发送触发
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5, repeats: false)

// 3. 发送请求标识符
let requestIdentifier = "com.onevcat.usernotification.myFirstNotification"

// 4. 创建一个发送请求
let request = UNNotificationRequest(identifier: requestIdentifier, content: content, trigger: trigger)

// 将请求添加到发送中心
UNUserNotificationCenter.current().add(request) { error in
    if error == nil {
        print("Time Interval Notification scheduled: \(requestIdentifier)")
    }
}

{
  "aps":{
    "alert":"Test",
    "sound":"default",
    "badge":1
  }
}

  "aps":{
    "alert":{
      "title":"I am title",
      "subtitle":"I am subtitle",
      "body":"I am body"
    },
    "sound":"default",
    "badge":1
  }
}

let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 3, repeats: false)
let identifier = "com.onevcat.usernotification.notificationWillBeRemovedAfterDisplayed"
let request = UNNotificationRequest(identifier: identifier, content: content, trigger: trigger)

UNUserNotificationCenter.current().add(request) { error in
    if error != nil {
        print("Notification request added: \(identifier)")
    }
}

delay(4) {
    print("Notification request removed: \(identifier)")
    UNUserNotificationCenter.current().removeDeliveredNotifications(withIdentifiers: [identifier])
}

// let request: UNNotificationRequest = ...
UNUserNotificationCenter.current().add(request) { error in
    if error != nil {
        print("Notification request added: \(identifier)")
    }
}

delay(2) {
    let newTrigger = UNTimeIntervalNotificationTrigger(timeInterval: 1, repeats: false)

    // Add new request with the same identifier to update a notification.
    let newRequest = UNNotificationRequest(identifier: identifier, content:newContent, trigger: newTrigger)
    UNUserNotificationCenter.current().add(newRequest) { error in
        if error != nil {
            print("Notification request updated: \(identifier)")
        }
    }
}

class NotificationHandler: NSObject, UNUserNotificationCenterDelegate {
    func userNotificationCenter(_ center: UNUserNotificationCenter, 
                       willPresent notification: UNNotification, 
                       withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) 
    {
        completionHandler([.alert, .sound])

        // 如果不想显示某个通知，可以直接用空 options 调用 completionHandler:
        // completionHandler([])
    }
}

class AppDelegate: UIResponder, UIApplicationDelegate {
    let notificationHandler = NotificationHandler()
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        UNUserNotificationCenter.current().delegate = notificationHandler
        return true
    }
}

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
    completionHandler()
}

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
    if let name = response.notification.request.content.userInfo["name"] as? String {
        print("I know it's you! \(name)")
    }
    completionHandler()
}

private func registerNotificationCategory() {
    let saySomethingCategory: UNNotificationCategory = {
        // 1
        let inputAction = UNTextInputNotificationAction(
            identifier: "action.input",
            title: "Input",
            options: [.foreground],
            textInputButtonTitle: "Send",
            textInputPlaceholder: "What do you want to say...")

        // 2
        let goodbyeAction = UNNotificationAction(
            identifier: "action.goodbye",
            title: "Goodbye",
            options: [.foreground])

        let cancelAction = UNNotificationAction(
            identifier: "action.cancel",
            title: "Cancel",
            options: [.destructive])

        // 3
        return UNNotificationCategory(identifier:"saySomethingCategory", actions: [inputAction, goodbyeAction, cancelAction], intentIdentifiers: [], options: [.customDismissAction])
    }()

    UNUserNotificationCenter.current().setNotificationCategories([saySomethingCategory])
}

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    registerNotificationCategory()
    UNUserNotificationCenter.current().delegate = notificationHandler
    return true
}

content.categoryIdentifier = "saySomethingCategory"

{
  "aps":{
    "alert":"Please say something",
    "category":"saySomething"
  }
}

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {

    if let category = UserNotificationCategoryType(rawValue: response.notification.request.content.categoryIdentifier) {
        switch category {
        case .saySomething:
            handleSaySomthing(response: response)
        }
    }
    completionHandler()
}

private func handleSaySomthing(response: UNNotificationResponse) {
    let text: String

    if let actionType = SaySomethingCategoryAction(rawValue: response.actionIdentifier) {
        switch actionType {
        case .input: text = (response as! UNTextInputNotificationResponse).userText
        case .goodbye: text = "Goodbye"
        case .none: text = ""
        }
    } else {
        // Only tap or clear. (You will not receive this callback when user clear your notification unless you set .customDismissAction as the option of category)
        text = ""
    }

    if !text.isEmpty {
        UIAlertController.showConfirmAlertFromTopViewController(message: "You just said \(text)")
    }
}

class NotificationService: UNNotificationServiceExtension {

    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNMutableNotificationContent?

    // 1
    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

        if let bestAttemptContent = bestAttemptContent {
            if request.identifier == "mutableContent" {
                bestAttemptContent.body = "\(bestAttemptContent.body), Andrew"
            }
            contentHandler(bestAttemptContent)
        }
    }

    // 2
    override func serviceExtensionTimeWillExpire() {
        // Called just before the extension will be terminated by the system.
        // Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
        if let contentHandler = contentHandler, let bestAttemptContent =  bestAttemptContent {
            contentHandler(bestAttemptContent)
        }
    }
}

{
  "aps":{
    "alert":{
      "title":"Greetings",
      "body":"Long time no see"
    },
    "mutable-content":1
  }
}

let content = UNMutableNotificationContent()
content.title = "Image Notification"
content.body = "Show me an image!"

if let imageURL = Bundle.main.url(forResource: "image", withExtension: "jpg"),
   let attachment = try? UNNotificationAttachment(identifier: "imageAttachment", url: imageURL, options: nil)
{
    content.attachments = [attachment]
}

{
  "aps":{
    "alert":{
      "title":"Image Notification",
      "body":"Show me an image from web!"
    },
    "mutable-content":1
  },
  "image": "https://onevcat.com/assets/images/background-cover.jpg"
}

private func downloadAndSave(url: URL, handler: @escaping (_ localURL: URL?) -> Void) {
    let task = URLSession.shared.dataTask(with: url, completionHandler: {
        data, res, error in

        var localURL: URL? = nil

        if let data = data {
            let ext = (url.absoluteString as NSString).pathExtension
            let cacheURL = URL(fileURLWithPath: FileManager.default.cachesDirectory)
            let url = cacheURL.appendingPathComponent(url.absoluteString.md5).appendingPathExtension(ext)

            if let _ = try? data.write(to: url) {
                localURL = url
            }
        }

        handler(localURL)
    })

    task.resume()
}

if let imageURLString = bestAttemptContent.userInfo["image"] as? String,
   let URL = URL(string: imageURLString)
{
    downloadAndSave(url: URL) { localURL in
        if let localURL = localURL {
            do {
                let attachment = try UNNotificationAttachment(identifier: "image_downloaded", url: localURL, options: nil)
                bestAttemptContent.attachments = [attachment]
            } catch {
                print(error)
            }
        }
        contentHandler(bestAttemptContent)
    }
}

let content = notification.request.content
if let attachment = content.attachments.first {  
    if attachment.url.startAccessingSecurityScopedResource() {  
        eventImage.image = UIImage(contentsOfFile: attachment.url.path!)  
        attachment.url.stopAccessingSecurityScopedResource()  
    }  
}  

if #available(iOS 10.0, *) {
    // Use UserNotification
}