[IOS] Image Notification Push 구현하기

- 4월 14, 2020

APNs를 이용해서 푸쉬를 보낼 수 있다는 가정하게 작성된 글 입니다.

Image Push Notification 만들기 (Using Notification Service Extension and Notification Content Extension).

기본적인 알림 기능이 동작하고 있다고 가정하고 설명합니다.

service extension과 content extension을 추가해줍니다.
Service extension은 Service라는 이름으로, Content extension은 Content라는 이름으로 추가 해 줍니다.

xcode > Editor > Add Target > Notification Service Extension > productname : "Service" > Next > Finish  
xcode > Editor > Add Target > Notification Content Extension > productname : "Content" > Next > Finish

추가 후 결과 화면은 다음과 같습니다.

Service > NotificationService.swift는 다음과 같습니다.

import UserNotifications

class NotificationService: UNNotificationServiceExtension {

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

    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)
        
        if let bestAttemptContent = bestAttemptContent {
            // Modify the notification content here...
            bestAttemptContent.title = "\(bestAttemptContent.title) [modified]"
            
            var urlString:String? = nil
            if let urlImageString = request.content.userInfo["urlImageString"] as? String {
                urlString = urlImageString
            }
            
            if urlString != nil, let fileUrl = URL(string: urlString!) {
                print("fileUrl: \(fileUrl)")
                
                guard let imageData = NSData(contentsOf: fileUrl) else {
                    contentHandler(bestAttemptContent)
                    return
                }
                guard let attachment = UNNotificationAttachment.saveImageToDisk(fileIdentifier: "image.jpg", data: imageData, options: nil) else {
                    print("error in UNNotificationAttachment.saveImageToDisk()")
                    contentHandler(bestAttemptContent)
                    return
                }
                
                bestAttemptContent.attachments = [ attachment ]
            }
            
            contentHandler(bestAttemptContent)
        }
    }
    
    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)
        }
    }

}

@available(iOSApplicationExtension 10.0, *)
extension UNNotificationAttachment {
    
    static func saveImageToDisk(fileIdentifier: String, data: NSData, options: [NSObject : AnyObject]?) -> UNNotificationAttachment? {
        let fileManager = FileManager.default
        let folderName = ProcessInfo.processInfo.globallyUniqueString
        let folderURL = NSURL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(folderName, isDirectory: true)
        
        do {
            try fileManager.createDirectory(at: folderURL!, withIntermediateDirectories: true, attributes: nil)
            let fileURL = folderURL?.appendingPathComponent(fileIdentifier)
            try data.write(to: fileURL!, options: [])
            let attachment = try UNNotificationAttachment(identifier: fileIdentifier, url: fileURL!, options: options)
            return attachment
        } catch let error {
            print("error \(error)")
        }
        
        return nil
    }
}

추가 후 다음과 같은 바디를 전송합니다.

{  
   "aps":{  
      "alert":"flowers for Hyunho!",
      "badge":1,
      "sound":"default",
      "category":"CustomSamplePush",
      "mutable-content":"1"
   },
   "urlImageString":"https://res.cloudinary.com/demo/image/upload/sample.jpg"
}