Cacheman NPM | npm.io

cacheman

Small and efficient cache provider for Node.JS with In-memory, File, Redis and MongoDB engines.

Installation

$ npm install cacheman

Usage

var Cacheman = require('cacheman');
var cache = new Cacheman();

// or
var cache = new Cacheman('todo');

// or
var cache = new Cacheman({ ttl: 90 });

// or
var cache = new Cacheman('todo', { ttl: 90 });

// set the value
cache.set('my key', { foo: 'bar' }, function (error) {

  if (error) throw error;

  // get the value
  cache.get('my key', function (error, value) {

    if (error) throw error;

    console.log(value); //-> {foo:"bar"}

    // delete entry
    cache.del('my key', function (error){

      if (error) throw error;

      console.log('value deleted');
    });

  });
});

API

Cacheman([name, options])

Create cacheman instance. It accepts an name(optional) and options(optional). options can contain ttl to set the default "Time To Live" in seconds, delimiter to change the delimiter used for array keys (default: ':'), Promise can set a Promise library to use for promises, engine that could be "memory", "in file", "redis" or "mongo", and the corresponding engine options that can be passed like port, host, etc.

You can also pass an already initialized client engine as valid engine so you can re-use among multiple cacheman instances.

By default cacheman uses the cacheman-memory engine.

var options = {
  ttl: 90,
  engine: 'redis',
  port: 9999,
  host: '127.0.0.1'
};

var cache = new Cacheman('todo', options);

Reuse engine in multiple cache instances:

var Cacheman = require('cacheman');
var EngineMongo = require('cacheman-mongo');
var engine = new Engine();

// Share same engine:
var todoCache = new Cacheman('todo', { engine: engine });
var blogCache = new Cacheman('blog', { engine: engine });

cache.set(key, value, [ttl, fn])

Stores or updates a value.

cache.set('foo', { a: 'bar' }, function (err, value) {
  if (err) throw err;
  console.log(value); //-> {a:'bar'}
});

cache.set('foo', { a: 'bar' })
  .then(function (value) {
    console.log(value); //-> {a:'bar'}
  });

Or add a TTL(Time To Live) in seconds like this:

// key will expire in 60 seconds
cache.set('foo', { a: 'bar' }, 60, function (err, value) {
  if (err) throw err;
  console.log(value); //-> {a:'bar'}
});

You can also use humman readable values for ttl like: 1s, 1m, etc. Check out the ms project for additional information on supported formats.

// key will expire in 45 seconds
cache.set('foo', { a: 'bar' }, '45s', function (err, value) {
  if (err) throw err;
  console.log(value); //-> {a:'bar'}
});

The key may also be an array. It will be joined into a string using the delimiter option.

// equivalent to setting 'foo:bar'
cache.set(['foo', 'bar'], { a: 'baz' }, function (err, value) {
  if (err) throw err;
  console.log(value); //-> {a:'baz'}
});

cache.get(key, fn)

Retrieves a value for a given key, if there is no value for the given key a null value will be returned.

cache.get('foo', function (err, value) {
  if (err) throw err;
  console.log(value);
});

cache.get('foo')
  .then(function (value) {
    console.log(value);
  });

cache.del(key, fn)

Deletes a key out of the cache.

cache.del('foo', function (err) {
  if (err) throw err;
  // foo was deleted
});

cache.del('foo')
  .then(function () {
    // foo was deleted
  });

cache.clear(fn)

Clear the cache entirely, throwing away all values.

cache.clear(function (err) {
  if (err) throw err;
  // cache is now clear
});

cache.clear()
  .then(function () {
    // cache is now clear
  });

cache.cache(key, data, ttl, fn)

Cache shortcut method that support middleware. This method will first call get and if the key is not found in cache it will call set to save the value in cache.

cache.cache('foo', { a: 'bar' }, '45s', function (err) {
  if (err) throw err;
  console.log(value); //-> {a:'bar'}
});

cache.cache('foo', { a: 'bar' }, '45s')
  .then(function () {
    console.log(value); //-> {a:'bar'}
  });

cache.use(fn)

This method allow to add middlewares that will be executed when the cache method is called, meaning that you can intercept the function right after the get and set methods.

For example we can add a middleware that will force ttl of 10 seconds on all values to cache:

function expireInMiddleware (expireIn) {
  return function (key, data, ttl, next) {
    next(null, data, expire);
  }
};

cache.use(expireInMiddleware('10s'));

cache.cache('foo', { a: 'bar' }, '45s', function (err) {
  if (err) throw err;
  console.log(value); //-> {a:'bar'}
});

Or we can add a middleware to overwrite the value:

function overwriteMiddleware (val) {
  return function (key, data, ttl, next) {
    next(null, val, expire);
  }
};

cache.use(overwriteMiddleware({ a: 'foo' }));

cache.cache('foo', { a: 'bar' }, '45s', function (err, data) {
  if (err) throw err;
  console.log(data); //-> {a:'foo'}
});

You can also pass errors as first argument to stop the cache execution:

function overwriteMiddleware () {
  return function (key, data, ttl, next) {
    next(new Error('There was an error'));
  }
};

cache.use(overwriteMiddleware());

cache.cache('foo', { a: 'bar' }, '45s', function (err) {
  if (err) throw err; // Will throw the error
});

cache.wrap(key, work, [ttl, fn])

Wraps a function in cache. The first time the function is run, its results are stored in cache so subsequent calls retrieve from cache instead of calling the function.

The work function can call a node style callback argument or return a value including a promise.

The work function and ttl can also be passed in the opposite order. This is primarily to make promise returning calls cleaner.

function work(callback) {
  callback(null, { a: 'foo' });
}

cache.wrap('foo', work, '45s', function (err, data) {
  console.log(data); //-> {a: 'foo'}
});

cache.wrap('foo', work, '45s')
  .then(function (data) {
    console.log(data); //-> {a: 'foo'}
  });

cache.wrap('foo', '45s',
  function() {
    return Promise.resolve({ a: 'foo' });
  })
  .then(function (data) {
    console.log(data); //-> {a: 'foo'}
  });

cache.wrap('foo', '45s',
  function() {
    return { a: 'foo' };
  })
  .then(function (data) {
    console.log(data); //-> {a: 'foo'}
  });

Run tests

$ make test

Supported engines

Credits

This library was inspired by the hilmi project.

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.