76b0025091
Updates descriptive text that refer to Zulip channels in the `docs/subsystems` files to use channel instead of stream. Part of the stream to channel rename project.
1.5 KiB
Unread message synchronization
In general displaying unread counts for all channels and topics may require downloading an unbounded number of messages. Consider a user who has a muted channel or topic and has not read the backlog in a month; to have an accurate unread count we would need to load all messages this user has received in the past month. This is inefficient for web clients and even more for mobile devices.
We work around this by including a list of unread message ids in the initial
state grouped by relevant conversation keys. This data is included in the
unread_msgs key if both update_message_flags and message are required
in the register call.
{
"count": 4,
"huddles": [
{
"user_ids_string": "3,4,6",
"unread_message_ids": [
34
]
}
],
"streams": [
{
"stream_id": 1,
"topic": "test",
"unread_message_ids": [
33
]
}
],
"pms": [
{
"sender_id": 3,
"unread_message_ids": [
31,
32
]
}
],
"mentions": [31, 34]
}
Three event types are required to correctly maintain the unread_msgs. New
messages can be created without the unread flag by the message event type.
The unread flag can be added and removed by the update_message_flags event,
and the topic of unread messages can be updated by the update_message event
type.