Create a notification attachment

createAttachment.swift

import UserNotifications
 
class ServiceExtension: UNNotificationServiceExtension
{
    struct Attachments {
        static let image = (identifier:"image", jsonElement:"imageURL")
    }
 
    var contentHandler: ((UNNotificationContent) -> Void)?
    var content: UNMutableNotificationContent?
 
    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler:(UNNotificationContent) -> Void)
    {
        self.contentHandler = contentHandler
        content = (request.content.mutableCopy() as? UNMutableNotificationContent)
        if let content = content {
            if let urlString = content.userInfo[Attachments.image.jsonElement] as? String, let attachmentURL = URL(string: urlString) {
                if let attachment = try? UNNotificationAttachment(identifier: Attachments.image.identifier, url: attachmentURL, options: nil) {
                    content.attachments = [attachment]
                }
            }
            return contentHandler(content)
        }
        contentHandler(request.content)
    }
 
    override func serviceExtensionTimeWillExpire()
    {
        if let contentHandler = contentHandler, let content =  content {
            contentHandler(content)
        }
    }
 
}