leverz / co-cache

Cache result in redis for GeneratorFunction or function that return a Promise.

co-cache

Cache result in redis for GeneratorFunction or function that return a Promise.

Install

npm i co-cache --save

Usage

var cache = require('co-cache')(defaultConfig);
cache(fn[, options]) => {GeneratorFunction|function->Promise}

defaultConfig {Object}:
options {Object|Number->expire}:

• client: {Object} redis client of ioredis.
• prefix: {String} prefix for redis cache, default ''.
• key: {String|GeneratorFunction|function->Promise} prefix + key == cacheKey, default function.name, if return false, skip get&set cache.
• expire: {Number->ms} expire in ms.
• get: {Function} function to get cache, default JSON.parse.
• set: {Function} function to set cache, default JSON.stringify.
• others options see ioredis

NB: If both defaultConfig and options missing, cache will not work.

Example

var cache = require('co-cache')();

var getIndex = cache(function getIndex() {
  return client.db('test').collection('test').find().limit(10).toArray();
}, 10000);

var getTopicsByPage = cache(function* getTopicsByPage(p) {
  p = p || 1;
  return yield client.db('test').collection('test').find().skip((p - 1) * 10).limit(10).toArray();
}, {
  prefix: 'cache:',
  key: function (p) { // or function*
    if (p >= 3) {
      return false; // only cache 1-2 pages
    }
    return this.name + ':' + (p || 1);
  },
  expire: 10000
});

co(function* () {
  getIndex().then(function () { ... });
  var topics = yield getTopicsByPage(2);
  ...
}).catch(onerror);

or use defaultConfig:

var cache = require('co-cache')({
  expire: 10 * 1000
});

var getIndex = cache(function getIndex() {
  return client.db('test').collection('test').find().limit(10).toArray();
});

var getTopicsByPage = cache(function* getTopicsByPage(p) {
  p = p || 1;
  return yield client.db('test').collection('test').find().skip((p - 1) * 10).limit(10).toArray();
}, {
  prefix: 'cache:',
  key: function (p) { // or function*
    if (p >= 3) {
      return false; // only cache 1-2 pages
    }
    return this.name + ':' + (p || 1);
  }
});

co(function* () {
  getIndex().then(function () { ... });
  var topics = yield getTopicsByPage(2);
  ...
}).catch(onerror);

Default get/set

function defaultGet(redis, cacheKey) {
  return redis.get(cacheKey).then(function (result) {
    if (result) {
      return JSON.parse(result);
    }
    return null;
  });
}

function defaultSet(redis, cacheKey, result, ms) {
  return redis.set(cacheKey, JSON.stringify(result), 'PX', ms);
}

Test

DEBUG=co-cache node --harmony example

License

MIT