iOS Swift Send Rich Push Notification Using Firebase Cloud Messaging

Question

I cannot get Firebase push notifications to work using an image. I am sending the payload through the FCM interface. When I fill out the "Notification Image" field using a link to an image, the image does not come through when testing on my device.

The push notification is sent successfully to my phone, however the image never appears.

I have setup a Notification Service Extension. Any help is greatly appreciated.

import UserNotifications
import FirebaseMessaging
import Foundation

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)
    
    guard let bestAttemptContent = bestAttemptContent,
        let attachmentUrlAsString = bestAttemptContent.userInfo["url"] as? String,
        let attachmentUrl = URL(string: attachmentUrlAsString) else {
            return
    }
    let mediaInfo = bestAttemptContent.userInfo
    Messaging.serviceExtension().populateNotificationContent(bestAttemptContent, withContentHandler: contentHandler)
    print("media info for push is: \(mediaInfo)")
    downloadImageFrom(url: attachmentUrl) { (attachment) in
        if let attachment = attachment {
            bestAttemptContent.attachments = [attachment]
            contentHandler(bestAttemptContent)
            Messaging.serviceExtension().populateNotificationContent(bestAttemptContent, withContentHandler: 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 {
        contentHandler(bestAttemptContent)
    }
}

}

extension NotificationService {
private func downloadImageFrom(url: URL, with completionHandler: @escaping (UNNotificationAttachment?) -> Void){
    let task = URLSession.shared.downloadTask(with: url) { (downloadedUrl, response, error) in
        //1. Test url and escape if url has problem
        guard let downloadedUrl = downloadedUrl else {
            completionHandler(nil)
            return
        }
        
        //2.
        var urlPath = URL(fileURLWithPath: NSTemporaryDirectory())
        let uniqueUrlEnding = ProcessInfo.processInfo.globallyUniqueString + ".jpg"
        urlPath = urlPath.appendingPathComponent(uniqueUrlEnding)
        
        try? FileManager.default.moveItem(at: downloadedUrl, to: urlPath)
        
        do {
            let attachment = try UNNotificationAttachment(identifier: "picture", url: urlPath, options: nil)
            completionHandler(attachment)
        } catch {
            completionHandler(nil)
        }
        
    }
    task.resume()
}
}

Answer 1

I solved it like this, applied to Firebase:

    guard let bestAttemptContent = bestAttemptContent,
        let fcmOptions = bestAttemptContent.userInfo["fcm_options"] as? [String: Any],
        let attachmentUrlAsString = fcmOptions["image"] as? String,
        let attachmentUrl = URL(string: attachmentUrlAsString) else {
            return
    }