iOS SDKのセットアップ

import UserNotifications
import OneSignalExtension

class NotificationService: UNNotificationServiceExtension {
    var contentHandler: ((UNNotificationContent) -> Void)?
    var receivedRequest: UNNotificationRequest!
    var bestAttemptContent: UNMutableNotificationContent?

    // Note this extension only runs when `mutable_content` is set
    // Setting an attachment or action buttons automatically sets the property to true
    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.receivedRequest = request
        self.contentHandler = contentHandler
        self.bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

        if let bestAttemptContent = bestAttemptContent {
            // DEBUGGING: Uncomment the 2 lines below to check this extension is executing
//            print("Running NotificationServiceExtension")
//            bestAttemptContent.body = "[Modified] " + bestAttemptContent.body

            OneSignalExtension.didReceiveNotificationExtensionRequest(self.receivedRequest, with: bestAttemptContent, withContentHandler: self.contentHandler)
        }
    }

    override func serviceExtensionTimeWillExpire() {
        // 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 {
            OneSignalExtension.serviceExtensionTimeWillExpireRequest(self.receivedRequest, with: self.bestAttemptContent)
            contentHandler(bestAttemptContent)
        }
    }
}