Listen using XREAD on one or more Streams on the
server Redis. For each message that arrives, call broadcast/1,
where Data is a dict representing the message.
broadcast(redis(Redis, Stream, Id, Data))
Options:
- count(+Count)
- Process at most Count messages per stream for each request.
- start(+Start)
- Normally either
0 to start get all messages from the epoch
or $ to get messages starting with the last. Default is $.
- starts(+List)
- May be used as an alternative to the start/1
option to specify the start for each stream. This may be used to restart
listening if the application remembers the last processed id.
Note that this predicate does not terminate. It is normally
executed in a thread. The following call listens to the streams
key1 and key2 on the default Redis
server. Using
reconnect(true), the client will try to re-establish a
connection if the collection got lost.
?- redis_connect(default, C, [reconnect(true)]),
thread_create(xlisten(C, [key1, key2], [start($)]),
_, [detached(true)]).
| Redis | is either a Redis server
name (see redis_server/3) or
an open connection. If it is a server name, a new connection is opened
that is closed if xlisten/3
completes. |
- See also
- redis_subscribe/2
implements the classical pub/sub system of
Redis that does not have any memory.
xlisten(+Redis,
+Streams, +Options)