memorystore

What is memorystore?

The 'memorystore' npm package is a session store for Express.js that uses a memory-based storage system. It is designed to be a simple and efficient way to store session data in memory, which can be useful for development and testing environments where persistence is not required.

What are memorystore's main functionalities?

Session Store Initialization

This code sample demonstrates how to initialize a session store using 'memorystore' in an Express.js application. The store is configured to prune expired entries every 24 hours, and sessions are set up with a maximum age of 24 hours.

const session = require('express-session');
const MemoryStore = require('memorystore')(session);

const store = new MemoryStore({
  checkPeriod: 86400000 // prune expired entries every 24h
});

app.use(session({
  cookie: { maxAge: 86400000 },
  store: store,
  resave: false,
  saveUninitialized: true,
  secret: 'your-secret-key'
}));

Other packages similar to memorystore

connect-redis

The 'connect-redis' package is a Redis-based session store for Express.js. It is suitable for production environments where session data needs to be persisted across server restarts. Unlike 'memorystore', which stores data in memory, 'connect-redis' uses Redis, a fast, in-memory data structure store, to persist session data.

express-session

While 'express-session' is a middleware for managing sessions in Express.js, it does not provide a storage mechanism by itself. It can be used with various session stores, including 'memorystore'. 'express-session' is more of a foundational package that requires a store like 'memorystore' or others to handle session data storage.

connect-mongo

The 'connect-mongo' package is a MongoDB-based session store for Express.js. It is ideal for applications that already use MongoDB as their database, allowing session data to be stored alongside other application data. Unlike 'memorystore', 'connect-mongo' provides persistent storage, making it suitable for production use.

README

memorystore

express-session full featured MemoryStore module without leaks!

A session store implementation for Express using lru-cache.

Because the default MemoryStore for express-session will lead to a memory leak due to it haven't a suitable way to make them expire.

The sessions are still stored in memory, so they're not shared with other processes or services.

Setup

$ npm install express-session memorystore

Pass the express-session store into memorystore to create a MemoryStore constructor.

var session = require('express-session')
var MemoryStore = require('memorystore')(session)

app.use(session({
    store: new MemoryStore({
      checkPeriod: 86400000 // prune expired entries every 24h
    }),
    secret: 'keyboard cat'
}))

Options

• checkPeriod Define how long MemoryStore will check for expired. The period is in ms. The automatic check is disabled by default! Not setting this is kind of silly, since that's the whole purpose of this lib.
• max The maximum size of the cache, checked by applying the length function to all values in the cache. It defaults to Infinity.
• ttl Session TTL (expiration) in milliseconds. Defaults to session.maxAge (if set), or one day. This may also be set to a function of the form (options, sess, sessionID) => number.
• dispose Function that is called on sessions when they are dropped from the cache. This can be handy if you want to close file descriptors or do other cleanup tasks when sessions are no longer accessible. Called with key, value. It's called before actually removing the item from the internal cache, so if you want to immediately put it back in, you'll have to do that in a nextTick or setTimeout callback or it won't do anything.
• stale By default, if you set a maxAge, it'll only actually pull stale items out of the cache when you get(key). (That is, it's not pre-emptively doing a setTimeout or anything.) If you set stale:true, it'll return the stale value before deleting it. If you don't set this, then it'll return undefined when you try to get a stale entry, as if it had already been deleted.
• serializer An object containing stringify and parse methods compatible with Javascript's JSON to override the serializer used.

Methods

memorystore implements all the required, recommended and optional methods of the express-session store. Plus a few more:

• startInterval() and stopInterval() methods to start/clear the automatic check for expired.

• prune() that you can use to manually remove only the expired entries from the store.

Debug

To enable debug set the env var DEBUG=memorystore

Author

Rocco Musolino (@roccomuso)

License

MIT