# Notification Service

> Notification service extension: rich push notification modification, media attachment downloads, content transformation before display. Use when customizing push notification content, downloading images for notifications, or modifying notification payloads. Triggers: UNNotificationServiceExtension, rich notification, push attachment, notification content.

- Skill: `abdullah4ai/notification-service` (Agent Skill)
- Install (CLI): `npx skillmds@latest add abdullah4ai/notification-service`
- Raw SKILL.md: https://api.skillmd.com/api/skills/abdullah4ai/notification-service/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: abdullah4ai (https://skillmd.com/u/abdullah4ai)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/abdullah4ai/notification-service

---

# Notification Service

NOTIFICATION SERVICE EXTENSION:
SETUP: Requires separate extension target (kind: "notification_service" in plan extensions array).
Used to modify rich push notification content before display (add images, decrypt payload, etc.).

PRINCIPAL CLASS (in extension):
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 else { contentHandler(request.content); return }

        // Modify content here — e.g., download and attach image
        if let urlString = request.content.userInfo["image_url"] as? String,
           let url = URL(string: urlString) {
            downloadAndAttach(url: url, to: bestAttemptContent) { modified in
                contentHandler(modified)
            }
        } else {
            bestAttemptContent.title = "[Modified] " + bestAttemptContent.title
            contentHandler(bestAttemptContent)
        }
    }

    override func serviceExtensionTimeWillExpire() {
        // Called just before extension is killed — deliver best attempt
        if let contentHandler, let bestAttemptContent {
            contentHandler(bestAttemptContent)
        }
    }
}

ADDING ATTACHMENT:
func downloadAndAttach(url: URL, to content: UNMutableNotificationContent, completion: @escaping (UNNotificationContent) -> Void) {
    URLSession.shared.downloadTask(with: url) { localURL, _, _ in
        if let localURL, let attachment = try? UNNotificationAttachment(identifier: "image", url: localURL) {
            content.attachments = [attachment]
        }
        completion(content)
    }.resume()
}