evanshortiss / expeditious-engine-memory

storage engine for expeditious that uses node.js process memory

expeditious-engine-memory

An in memory engine for expeditious. Cache entries are - you guessed it - stored in the node.js process memory. This cache engine will lose everything stored if your process restarts, and could lead to memory bloat and slow garbage collections if you're not careful with the size and volume of entries!

Usage

You can use this module standalone or with expeditious which is the recommended approach since it simplifies interactions and allows you to easily switch cache engines.

var expeditious = require('expeditious');

var countries = expeditious({
  // Use the expeditious memory engine
  engine: require('expeditious-engine-memory')(),
  // Prefix all entries with 'countries'
  namespace: 'countries',
  // Auto parse json entries
  objectMode: true,
  // 1 hour timeout for entries
  defaultTtl: (60 * 1000 * 60),
});

countries.set({
  key: 'ireland',
  value: {
    population: '4.595 million',
    capital: 'Dublin'
  }
}, function (err) {
  if (!err) {
    console.error('failed to add "ireland" to the cache');
  } else {
    console.log('add "ireland" to the cache');
  }
});

API

Each API function takes a callback function as the last parameter and it receives up to two arguments as per node.js convention, error err and an optional result, res.

set(key, value, expire, callback)

Set a key (String) in the cache with a given (String) value. expire must be a Number greater than 0.

get(key, callback)

Get a specific item from the cache. Returns null if the entry is not found.

del(key, callback)

Delete a specific item from the cache. Callback receives only an error parameter.

keys(callback)

List all keys that this engine instance contains.

ttl(key, callback)

Get the time left before key expires. Returns null as res if the entry is not found.

flush(callback)

Flush all items from the engine instance.