Changeset

--- a/mod_cloud_notify/README.markdown	Sat Sep 24 08:28:07 2022 +0100
+++ b/mod_cloud_notify/README.markdown	Sat Sep 24 09:25:46 2022 +0100
@@ -7,17 +7,62 @@
 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 included[^1].
+This module enables support for sending "push notifications" to clients that
+need it, typically those running on certain mobile devices.
 
-**Please note: Multi client setups don't work properly if MAM is disabled and using this module won't change this at all!**
+As well as this module, your client must support push notifications (the apps
+that need it generally do, of course) and the app developer's push gateway
+must be reachable from your Prosody server (this happens over a normal XMPP
+server-to-server 's2s' connection).
 
 Details
 =======
 
+Some platforms, notably Apple's iOS and many versions of Android, impose
+limits that prevent applications from running or accessing the network in the
+background. This makes it difficult or impossible for an XMPP application to
+remain reliably connected to a server to receive messages.
+
+In order for messaging and other apps to receive notifications, the OS vendors
+run proprietary servers that their OS maintains a permanent connection to in
+the background. Then they provide APIs to application developers that allow
+sending notifications to specific devices via those servers.
+
+When you connect to your server with an app that requires push notifications,
+it will use this module to set up a "push registration". When you receive
+a message but your device is not connected to the server, this module will
+generate a notification and send it to the push gateway operated by your
+application's developers). Their gateway will then connect to your device's
+OS vendor and ask them to forward the notification to your device. When your
+device receives the notification, it will display it or wake up the app so it
+can connect to XMPP and receive any pending messages.
+
+This protocol is described for developers in [XEP-0357: Push Notifications].
+
+For this module to work reliably, you must have [mod_smacks], [mod_mam] and
+[mod_carbons] also enabled on your server.
+
+Some clients, notably Siskin and Snikket iOS need some additional extensions
+that are not currently defined in a standard XEP. To support these clients,
+see [mod_cloud_notify_extensions].
+
+Configuration
+=============
+
+  Option                               Default           Description
+  ------------------------------------ ----------------- -------------------------------------------------------------------------------------------------------------------
+  `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_errors`                    `16`              How much persistent push errors are tolerated before notifications for the identifier in question are disabled
+  `push_max_devices`                   `5`               The number of allowed devices per user (the oldest devices are automatically removed if this threshold is reached)
+  `push_max_hibernation_timeout`       `259200` (72h)    Number of seconds to extend the smacks timeout if no push was triggered yet (default: 72 hours)
+  `push_notification_with_body` (\*)   `false`           Whether or not to send the real message body to remote pubsub node. Without end-to-end encryption, enabling this may expose your message contents to your client developers and OS vendor. Not recommended.
+  `push_notification_with_sender` (\*) `false`           Whether or not to send the real message sender to remote pubsub node.  Enabling this may expose your contacts to your client developers and OS vendor. Not recommended.
+
+(\*) There are privacy implications for enabling these options.
+
+Internal design notes
+=====================
+
 App servers are notified about offline messages, messages stored by [mod_mam]
 or messages waiting in the smacks queue.
 The business rules outlined [here](//mail.jabber.org/pipermail/standards/2016-February/030925.html) are all honored[^2].
@@ -45,32 +90,6 @@
 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 real message body to remote pubsub node. Without end-to-end encryption, enabling this may expose your message contents to your client developers and OS vendor. Not recommended.
-  `push_notification_with_sender`      `false`           Whether or not to send the real message sender to remote pubsub node.  Enabling this may expose your contacts to your client developers and OS vendor. Not recommended.
-  `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)
-  `push_max_hibernation_timeout`       `6220800`         Number of seconds to extend the smacks timeout if no push was triggered yet (default: 72 hours)
-
-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
 =============