connect-redis

What is connect-redis?

The connect-redis npm package is a Redis session store for Express and Connect. It allows you to store session data in a Redis database, which can help with scaling applications by providing a centralized session store.

What are connect-redis's main functionalities?

Basic Setup

This code demonstrates how to set up a basic Express application with connect-redis as the session store. It configures the session middleware to use Redis for storing session data.

const session = require('express-session');
const RedisStore = require('connect-redis')(session);
const express = require('express');
const app = express();

app.use(session({
  store: new RedisStore({
    host: 'localhost',
    port: 6379
  }),
  secret: 'your secret',
  resave: false,
  saveUninitialized: false
}));

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

Custom Redis Client

This code demonstrates how to use a custom Redis client with connect-redis. This can be useful if you need to configure the Redis client with specific options or use an existing Redis client instance.

const session = require('express-session');
const RedisStore = require('connect-redis')(session);
const express = require('express');
const redis = require('redis');
const app = express();

const redisClient = redis.createClient({
  host: 'localhost',
  port: 6379
});

app.use(session({
  store: new RedisStore({ client: redisClient }),
  secret: 'your secret',
  resave: false,
  saveUninitialized: false
}));

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

Advanced Configuration

This code demonstrates advanced configuration options for connect-redis, such as setting the time-to-live (ttl) for sessions and enabling error logging.

const session = require('express-session');
const RedisStore = require('connect-redis')(session);
const express = require('express');
const app = express();

app.use(session({
  store: new RedisStore({
    host: 'localhost',
    port: 6379,
    ttl: 260,
    logErrors: true
  }),
  secret: 'your secret',
  resave: false,
  saveUninitialized: false
}));

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

Other packages similar to connect-redis

express-session

express-session is a general-purpose session middleware for Express. It supports various session stores, including in-memory, file-based, and database-backed stores. Unlike connect-redis, it does not provide a Redis-specific store out of the box but can be extended with other packages.

connect-mongo

connect-mongo is a MongoDB session store for Express and Connect. It provides similar functionality to connect-redis but uses MongoDB as the backend store instead of Redis. It is useful for applications that already use MongoDB and want to keep session data in the same database.

express-mysql-session

express-mysql-session is a MySQL session store for Express. It provides similar functionality to connect-redis but uses MySQL as the backend store. It is useful for applications that use MySQL and want to store session data in a relational database.

README

connect-redis is a Redis session store backed by node_redis, and is insanely fast :). Requires redis >= 2.0.0 for the SETEX command.

Setup

npm install connect-redis express-session

Pass the express-session store into connect-redis to create a RedisStore constructor.

var session = require('express-session');
var RedisStore = require('connect-redis')(session);

app.use(session({
    store: new RedisStore(options),
    secret: 'keyboard cat',
    resave: false
}));

Options

A Redis client is required. An existing client can be passed directly using the client param or created for you using the host, port, or socket params.

• client An existing client
• host Redis server hostname
• port Redis server portno
• socket Redis server unix_socket
• url Redis server url

The following additional params may be included:

• ttl Redis session TTL (expiration) in seconds. Defaults to session.cookie.maxAge (if set), or one day.
  • This may also be set to a function of the form (store, sess, sessionID) => number.
• disableTTL Disables setting TTL, keys will stay in redis until evicted by other means (overides ttl)
• db Database index to use. Defaults to Redis's default (0).
• pass Password for Redis authentication
• prefix Key prefix defaulting to "sess:"
• unref Set true to unref the Redis client. Warning: this is an experimental feature.
• serializer An object containing stringify and parse methods compatible with Javascript's JSON to override the serializer used
• logErrors Whether or not to log client errors. (default: false)
  • If true, a default logging function (console.error) is provided.
  • If a function, it is called anytime an error occurs (useful for custom logging)
  • If false, no logging occurs.
• scanCount Value used for count parameter in Redis SCAN command (used in ids() and all() methods, defaults to 100).

Any options not included in this list will be passed to the redis createClient() method directly.

Custom Redis clients

Clients other than node_redis will work if they support the same interface. Just pass the client instance as the client configuration option. Known supported clients include:

• ioredis - adds support for Redis Sentinel and Cluster

Testing / Development

You can use redis-mock as the client instead of connecting to an actual redis server for automated testing and development purposes.

FAQ

How do I handle lost connections to Redis?

By default, the node_redis client will auto-reconnect when a connection is lost. But requests may come in during that time. In Express, this scenario can be handled by including a "session check".

app.use(session( /* setup session here */ ))
app.use(function (req, res, next) {
  if (!req.session) {
    return next(new Error('oh no')) // handle error
  }
  next() // otherwise continue
})

If you want to retry, here is another option.

License

MIT