CNN Caching

Makes working with caching easier. Now with hash ring support!

Fork of mape/node-caching

Installation

Via npm:

$ npm install cnn-caching

Built in stores

• Memory
• Redis
• Hash Ring

Pseudo-code Example

var Caching = require('cnn-caching');
var cache = new Caching('redis'); /* use 'memory', 'redis' or 'hashring' */

var ttl = 60 * 1000; // 1minute;
cache('twitter-users', ttl, function(passalong) {
    getMostActiveTwitterUser(function(err, userName) {
        fetchTwitterFollowers(userName, passalong); // passalong replaces function(err, userList) {}
    })
}, function(err, userList) {
    console.log(userList);
});

Memory Code Example

var Caching = require('cnn-caching');
var cache = new Caching();

setInterval(function() {
    cache('key', 10000 /*ttl in ms*/, function(passalong) {
        // This will only run once, all following requests will use cached data.
        setTimeout(function() {
            passalong(null, 'Cached result');
        }, 1000);
    }, function(err, results) {
        // This callback will be reused each call
        console.log(results);
    });
}, 100);

Redis Code Example

var Caching = require('cnn-caching');
var cache = new Caching('redis');

setInterval(function() {
    cache('key', 10000 /*ttl in ms*/, function(passalong) {
        // This will only run once, all following requests will use cached data.
        setTimeout(function() {
            passalong(null, 'Cached result');
        }, 1000);
    }, function(err, results) {
        // This callback will be reused each call
        console.log(results);
    });
}, 100);

Hash Ring Code Example

var Caching = require('cnn-caching');
var cache = new Caching('hashring', {
        "servers": 'http://localhost:6377,http://localhost:6378,http://localhost:6379,http://localhost:6380',
        "max cache size": 10000,  /* Any node-hashing options allowed */
        "minTtl": 10  /* Minimum TTL that cnn-caching will actually cache (default 0) */
    });

setInterval(function() {
    cache('key', 10000 /*ttl in ms*/, function(passalong) {
        // This will only run once, all following requests will use cached data.
        setTimeout(function() {
            passalong(null, 'Cached result');
        }, 1000);
    }, function(err, results) {
        // This callback will be reused each call
        console.log(results);
    });
}, 100);

Api

cache(key, ttl, runIfNothingInCache, useReturnedCachedResults);

arguments[0]

Key, 'myKey'

arguments[1]

Time To Live in ms, 60*30*1000

arguments[2]

Callback that will run if results aren't already in cache store.

function (passalong) {
    setTimeout(function() {
        passalong(null, 'mape', 'frontend developer', 'sweden');
    }, 1000);
}

arguments[3]

Callback that is called every time the method runs.

function(err, result) {
    console.log(name, result);
}