1.5 KiB
Room Previews
It is sometimes desirable to offer a preview of a room, where a user can "lurk" and read messages posted to the room, without joining the room. This can be particularly effective when combined with Guest Access.
Previews are implemented via the world_readable Room History
Visibility. setting, along with a special version of the GET
/events endpoint.
Client behaviour
A client wishing to view a room without joining it should call GET /rooms/:room_id/initialSync, followed by GET /events. Clients will need to do this in parallel for each room they wish to view.
Clients can of course also call other endpoints such as GET
/rooms/:room_id/messages
and GET /search to
access events outside the /events stream.
{{% http-api spec="client-server" api="peeking_events" %}}
Server behaviour
For clients which have not joined a room, servers are required to only
return events where the room state at the event had the
m.room.history_visibility state event present with
history_visibility value world_readable.
Security considerations
Clients may wish to display to their users that rooms which are
world_readable may be showing messages to non-joined users. There is
no way using this module to find out whether any non-joined guest users
do see events in the room, or to list or count any lurking users.