Python client for Apple Push Notification service (APNs)
Check the client with similar interface for Google Cloud Messaging.
- six - Python 2 and 3 compatibility library.
- pyOpenSSL - OpenSSL wrapper. Required by standard networking back-end.
Standard library has support for SSL transport. However, it is impossible to use it with certificates provided as a string. We store certificates in database, because we handle different apps on many Celery worker machines. A dirty solution would be to create temporary files, but it is insecure and slow. So, we have decided to use a better OpenSSL wrapper and pyOpenSSL was the easiest to handle. pyOpenSSL is loaded on demand by standard networking back-end. If you use your own back-end, based on some other SSL implementation, then you don’t have to install pyOpenSSL.
- Support certificates from strings. We do not distribute certificate files on worker machines, they fetch it from the database when needed. This approach simplifies deployment, upgrades and maintenance.
- Keep connections persistent. An SSL handshaking round is slow. Once connection is established, it should remain open for at least few minutes, waiting for the next batch.
- Support enhanced format. Apple developers have designed a notoriously bad push protocol. They have upgraded it to enhanced version, which makes it possible to detect which messages in the batch have failed.
- Clean pythonic API. No need for lots of classes, long lists of exceptions etc.
- Do not hard-code validation, let APNs fail. This decision makes library a little bit more future proof.
- Networking layer became pluggable, making gevent based implementations possible. Everything is refactored, such that IO, multi-threading and SSL are now loaded and used on demand, allowing you to cleanly override any part of the client. The API is largely backward compatible. IO related configuration is moved to transport layer and exception handling is a bit more verbose. The client is using standard logging to send fine grained debug messages.
- First simple implementation, hardwired with raw sockets and pyOpenSSL. It does not work in gevent or any other green environment.