redis-command-cache

Sometimes we need to run at such an high pace that we cannot hit redis every time. We must cache values locally, and invalidate it at any change.

This module uses lru-cache.

Usage

var redis = require("redis");
var redisCache = require("redis-command-cache");
 
var size = 500; //Max size of local lru-cache, defaults to 500
var ttl = 600; //Time-to-live on local and redis cache in seconds, local defaults to 10
               //minutes, redis defaults to no ttl (always stays in redis cache)
var cache = redisCache(db.createClient(), db.createClient(), size, ttl);
// var cache = redisCache(db.createClient(), db.createClient()); => local size 500, ttl on local 10 min, no ttl on redis
 
cache.set("key", "aaa", function() {
  cache.get("key", function(err, value) {
    // this value is cached until another set happens
    // you might get stale data
  });
});

Supported Commands

The following commands have the same signature of node-redis, but they invalidate all the connected caches.

• get()
• set()
• del()
• sadd()
• srem()
• smembers()

How

redis-command-cache uses two redis connections one of which is used for a pubsub channel for key invalidations. It assumes that the number of writes on cached data is lower than the number of reads by some order of magnitude.

License

Copyright (c) 2014, Matteo Collina hello@matteocollina.com All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.