Added OneSignal

ios/App/OneSignalNotificationServiceExtension/NotificationService.swift

@@ -0,0 +1,35 @@
+import UserNotifications
+
+import OneSignalExtension
+
+class NotificationService: UNNotificationServiceExtension {
+    
+    var contentHandler: ((UNNotificationContent) -> Void)?
+    var receivedRequest: UNNotificationRequest!
+    var bestAttemptContent: UNMutableNotificationContent?
+    
+    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
+                          Note, this extension only runs when mutable-content is set
+                          Setting an attachment or action buttons automatically adds this */
+            // print("Running NotificationServiceExtension")
+            // bestAttemptContent.body = "[Modified] " + bestAttemptContent.body
+            
+            OneSignalExtension.didReceiveNotificationExtensionRequest(self.receivedRequest, with: bestAttemptContent, withContentHandler: self.contentHandler)
+        }
+    }
+    
+    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 {
+            OneSignalExtension.serviceExtensionTimeWillExpireRequest(self.receivedRequest, with: self.bestAttemptContent)
+            contentHandler(bestAttemptContent)
+        }
+    }
+}