dirty-cache

Basic wrapper around lru-cache that uses pub-sub for notifying of a dirty entry. Not all lru-cache functionality is exposed, mainly get, set, and del.

One difference to be aware of, values in cache are a deep clone of the inserted value so that any modifications made to the object before or after being cached don't change modify the object in cache.

var obj = {foo: 'bar'};
cache.set(1, obj);
 
obj == cache.get(1); // false
obj.foo == cache.get(1).foo; // true

Usage

var dirtyCache = require('dirty-cache');
 
var cache1 = dirtyCache({name: 'users', max: 100, maxAge: 60000, redis: {host: 'localhost', port: 6379}});
var cache2 = dirtyCache({name: 'users', max: 100, maxAge: 60000, redis: {host: 'localhost', port: 6379}});
 
cache1.set('0087e434-9dfe-4ac9-99e9-fbdbd9f834f5', {name: 'TJ'});
cache1.get('0087e434-9dfe-4ac9-99e9-fbdbd9f834f5'); // {name: 'TJ'}
 
cache2.set('0087e434-9dfe-4ac9-99e9-fbdbd9f834f5', {name: 'TJ', age: 31}, true);
 
cache1.get('0087e434-9dfe-4ac9-99e9-fbdbd9f834f5'); // undefined
cache2.get('0087e434-9dfe-4ac9-99e9-fbdbd9f834f5'); // {name: 'TJ', age: 31}

Options

• name The name of this cache. Needed when using same cache on distributed system. Optional or not needed when used as a standalone cache.
• max The maximum number of objects in the cache, Not setting this is kind of silly, since that's the whole purpose of this lib, but it defaults to Infinity.
• maxAge Maximum age in ms. Items are not pro-actively pruned out as they age, but if you try to get an item that is too old, it'll drop it and return undefined instead of giving it to you.
• redis.host Redis host
• redis.port Redis port
• redis.password Redis password (if needed)

API

set(key, value, dirty)

Sets the value of key in the local cache. If dirty, notifies other caches their value is stale.

get(key)

Gets the latest value of key, or undefined if was not present in local cache or has been evicted due to dirtiness or expiration.

del(key)

Deletes a key out of the local cache and notifies distributed caches to evict key.

Events

"error"

Error event in the case of connection errors to redis.

"ready"

Client will emit ready after the conenction to redis has been successfully established.