Awesome

metatext-apns

This is a simple service to relay WebPush notifications to Apple's push notification service. It was designed for Metatext, an iOS Mastodon client, but could theoretically be used for other purposes.

Setup

Environment

metatext-apns uses a token-based connection. You will need to set the following environment variables based on a key generated in the Apple developer portal:

• APNS_KEY_ID
• APNS_AUTH_KEY

You will also need to set these:

• APPLE_TEAM_ID
• TOPIC

Finally, you will need to specify the size of the connection pool:

• CONNECTION_POOL_SIZE

Client

The service sets { "loc-key" : "apns-default-message" } for the alert key of the aps payload dictionary. If decrypting the notification on the client fails, the value for "apns-default-message" in your Localizable.strings file is what will be displayed.

Usage

Register your push subscription to call the endpoint /push/:device_token/:id (adding ?sandbox=true for debug builds) on the domain you are hosting the service, where device_token is the device token received in application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) in the client as a Base16 string and id is an identifier for which account on the client the notification belongs to. The service will deliver notifications with the mutable-content key set to 1 so a notification service extension can decrypt them. The notifications will have these keys in their custom payload:

• i: The id path component of the subscription URL
• m: The encrypted message as a URL-safe Base64 string
• s: The salt as a URL-safe Base64 string
• k: The server's public key as a URL-safe Base64 string

See Metatext's notification service extension and push notification parsing service for an example of how to decrypt the notifications in a notification service extension.

Deployment

metatext-apns is a Sinatra application, and can be deployed like any other Rack-based application. It is set up to be run using the Puma web server.

License

Copyright (C) 2021 Metabolist

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see https://www.gnu.org/licenses/.