Streaming data pubsub - node.js + redis

node-redis-data-pubsub.js

var redis = require('redis');

var pubcli = redis.createClient(6380, '127.0.0.1');

var subcli = redis.createClient(6380, '127.0.0.1');
var datacli = redis.createClient(6380, '127.0.0.1', {return_buffers:true});

var have = 0;
datacli.lrange('data.theresource', 0, -1, function(err,chunks) {
  console.log("initial data!",chunks);
  have = chunks.length;
});

subcli.on("subscribe", function(channel, count) {
  console.log("subscribe!", channel, count);
});
subcli.on("message", function(channel, message) {
  var need = parseInt(message);
  console.log("list is now "+need+" items long");
  if (have >= need) return; // needed in case we fetch the list before the publish about it
  datacli.lrange('data.theresource',have,need-1,function(err,chunks) {
    console.log("data!",chunks);
  });
  have = need;
});

subcli.subscribe("pubsub.theresource");

setTimeout(function() {
  var binary = new Buffer(4);
  binary[0] = 0;
  binary[1] = 1;
  binary[2] = 2;
  binary[3] = 3;
  pubcli.rpush("data.theresource", binary, function(err,newSize) {
    console.log("pushed",arguments);
    pubcli.publish("pubsub.theresource",""+newSize);
  });
},800);

setTimeout(function() {
  var binary = new Buffer(0);
  pubcli.rpush("data.theresource", binary, function(err,newSize) {
    console.log("pushed",arguments);
    pubcli.publish("pubsub.theresource",""+newSize);
  });
},1600);