mod_cloud_notify

Introduction

This is an implementation of the server bits of XEP-0357: Push Notifications. It allows clients to register an “app server” which is notified about new messages while the user is offline, disconnected or the session is hibernated by mod_smacks. Implementation of the “app server” is not included1.

Please note: Multi client setups don’t work properly if MAM is disabled and using this module won’t change this at all!

Details

App servers are notified about offline messages, messages stored by mod_mam or messages waiting in the smacks queue. The business rules outlined here are all honored2.

To cooperate with mod_smacks this module consumes some events: smacks-ack-delayed, smacks-hibernation-start and smacks-hibernation-end. These events allow this module to send out notifications for messages received while the session is hibernated by mod_smacks or even when smacks acknowledgements for messages are delayed by a certain amount of seconds configurable with the mod_smacks setting smacks_max_ack_delay.

The smacks_max_ack_delay setting allows to send out notifications to clients which aren’t already in smacks hibernation state (because the read timeout or connection close didn’t already happen) but also aren’t responding to acknowledgement request in a timely manner. This setting thus allows conversations to be smoother under such circumstances.

The new event cloud-notify-ping can be used by any module to send out a cloud notification to either all registered endpoints for the given user or only the endpoints given in the event data.

The config setting push_notification_important_body can be used to specify an alternative body text to send to the remote pubsub node if the stanza is encrypted or has a body. This way the real contents of the message aren’t revealed to the push appserver but it can still see that the push is important. This is used by Chatsecure on iOS to send out high priority pushes in those cases for example.

Configuration

Option Default Description
push_notification_with_body false Whether or not to send the message body to remote pubsub node.
push_notification_with_sender false Whether or not to send the message sender to remote pubsub node.
push_max_errors 16 How much persistent push errors are tolerated before notifications for the identifier in question are disabled
push_notification_important_body New Message! The body text to use when the stanza is important (see above), no message body is sent if this is empty
push_max_devices 5 The number of allowed devices per user (the oldest devices are automatically removed if this threshold is reached)

There are privacy implications for enabling these options because plaintext content and metadata will be shared with centralized servers (the pubsub node) run by arbitrary app developers.

Installation

Same as any other module.

Configuration

Configured in-band by supporting clients.

Compatibility

Should work with 0.9+.


  1. The service which is expected to forward notifications to something like Google Cloud Messaging or Apple Notification Service

  2. business_rules.markdown