node.js - Socket.io: How to count clients in a room with Socket.io-redis adapter -

i start building chat server using socket.io multiple nodes. uses socket.io-redis connect servers , rooms messaging.

when client connects server join client room.

io.on('connection', function(socket){   socket.join("client_1"); }); 

so want number of clients connected room "client_1",

io.sockets.adapter.rooms["client_1"]; 

but connection current process. how can connection server processes connected through redis adapter?

i have gone through question:

how check socket alive (connected) in socket.io multiple nodes , socket.io-redis

but didn't me.

thanks advance.

as of writing:

the redis adapter extends base adapter, overrides/adds following properties:

• onmessage
• broadcast
• add
• del
• delall

---

with code of yours:

io.sockets.adapter.rooms["client_1"]; 

you querying the rooms property. this wasn't overridden redis adapter, you're querying base adapter, knows rooms/clients in current process.

why didn't redis adapter override rooms property? because in order match exact call signature above, have query redis instance construct object containing rooms , connections every time property accessed. not good. (that unless can figure out how compute object values @ time values queried.)

if want number of connections "client_1" room across processes in cluster, you'll have add functionality the adapter itself method this:

/**    * count number of connections in room.    *    * @param {string} room id    * @param {function} callback (optional)    * @api public    */    redis.prototype.numclients = function(room, fn){ ... } 

wherein you'll query redis db instance.

imo, should part of base adapter interface other adapters implement. it's common problem.