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connect-mongo

MongoDB session store for Connect and Express

Compatibility

Support Express up to 5.0
Support all Connect versions
Support Mongoose >= 4.1.2+
Support native MongoDB driver >= 2.0.36
Support Node.js 4, 6, 8 and 10
Support MongoDB >= 3.0

For extended compatibility, see previous versions.

Usage

Express or Connect integration

Express 4.x, 5.0 and Connect 3.x:

const session = require('express-session');
const MongoStore = require('connect-mongo')(session);

app.use(session({
    secret: 'foo',
    store: new MongoStore(options)
}));

Express 2.x, 3.x and Connect 1.x, 2.x:

const MongoStore = require('connect-mongo')(express);

app.use(express.session({
    secret: 'foo',
    store: new MongoStore(options)
}));

For Connect 1.x and 2.x, just replace express by connect.

Connection to MongoDB

In many circumstances, connect-mongo will not be the only part of your application which need a connection to a MongoDB database. It could be interesting to re-use an existing connection.

Alternatively, you can configure connect-mongo to establish a new connection.

Re-use a Mongoose connection

const mongoose = require('mongoose');

// Basic usage
mongoose.connect(connectionOptions);

app.use(session({
    store: new MongoStore({ mongooseConnection: mongoose.connection })
}));

// Advanced usage
const connection = mongoose.createConnection(connectionOptions);

app.use(session({
    store: new MongoStore({ mongooseConnection: connection })
}));

Re-use a native MongoDB driver connection (or a promise)

In this case, you just have to give your Db instance to connect-mongo. If the connection is not opened, connect-mongo will do it for you.

/*
** There are many ways to create dbInstance.
** You should refer to the driver documentation.
*/

app.use(session({
    store: new MongoStore({ db: dbInstance })
}));

Or just give a promise…

app.use(session({
    store: new MongoStore({ dbPromise: dbInstancePromise })
}));

Create a new connection from a MongoDB connection string

MongoDB connection strings are the best way to configure a new connection. For advanced usage, more options can be configured with mongoOptions property.

// Basic usage
app.use(session({
    store: new MongoStore({ url: 'mongodb://localhost/test-app' })
}));

// Advanced usage
app.use(session({
    store: new MongoStore({
        url: 'mongodb://user12345:foobar@localhost/test-app?authSource=admins&w=1',
        mongoOptions: advancedOptions // See below for details
    })
}));

Events

A MongoStore instance will emit the following events:

Event name	Description	Payload
`create`	A session has been created	`sessionId`
`touch`	A session has been touched (but not modified)	`sessionId`
`update`	A session has been updated	`sessionId`
`set`	A session has been created OR updated (for compatibility purpose)	`sessionId`
`destroy`	A session has been destroyed	`sessionId`

Session expiration

When the session cookie has an expiration date, connect-mongo will use it.

Otherwise, it will create a new one, using ttl option.

app.use(session({
    store: new MongoStore({
      url: 'mongodb://localhost/test-app',
      ttl: 14 * 24 * 60 * 60 // = 14 days. Default
    })
}));

Note: Each time an user interacts with the server, its session expiration date is refreshed.

Remove expired sessions

By default, connect-mongo uses MongoDB’s TTL collection feature (2.2+) to have mongod automatically remove expired sessions. But you can change this behavior.

Set MongoDB to clean expired sessions (default mode)

connect-mongo will create a TTL index for you at startup. You MUST have MongoDB 2.2+ and administration permissions.

app.use(session({
    store: new MongoStore({
      url: 'mongodb://localhost/test-app',
      autoRemove: 'native' // Default
    })
}));

Note: If you use connect-mongo in a very concurrent environment, you should avoid this mode and prefer setting the index yourself, once!

Set the compatibility mode

You have an older MongoDB version (compatible with connect-mongo) or you can’t or don’t want to create a TTL index.

connect-mongo will take care of removing expired sessions, using defined interval.

app.use(session({
    store: new MongoStore({
      url: 'mongodb://localhost/test-app',
      autoRemove: 'interval',
      autoRemoveInterval: 10 // In minutes. Default
    })
}));

Disable expired sessions cleaning

You are in production environnement and/or you manage the TTL index elsewhere.

app.use(session({
    store: new MongoStore({
      url: 'mongodb://localhost/test-app',
      autoRemove: 'disabled'
    })
}));

Lazy session update

If you are using express-session >= 1.10.0 and don’t want to resave all the session on database every single time that the user refresh the page, you can lazy update the session, by limiting a period of time.

app.use(express.session({
    secret: 'keyboard cat',
    saveUninitialized: false, // don't create session until something stored
    resave: false, //don't save session if unmodified
    store: new MongoStore({
        url: 'mongodb://localhost/test-app',
        touchAfter: 24 * 3600 // time period in seconds
    })
}));

by doing this, setting touchAfter: 24 * 3600 you are saying to the session be updated only one time in a period of 24 hours, does not matter how many request’s are made (with the exception of those that change something on the session data)

More options

collection Collection (default: sessions)
fallbackMemory Fallback to MemoryStore. Useful if you want to use MemoryStore in some case, like in development environment.
stringify If true, connect-mongo will serialize sessions using JSON.stringify before setting them, and deserialize them with JSON.parse when getting them. (optional, default: true). This is useful if you are using types that MongoDB doesn’t support.
serialize Custom hook for serializing sessions to MongoDB. This is helpful if you need to modify the session before writing it out.
unserialize Custom hook for unserializing sessions from MongoDB. This can be used in scenarios where you need to support different types of serializations (e.g., objects and JSON strings) or need to modify the session before using it in your app.
transformId (optional) Transform original sessionId in whatever you want to use as storage key.

Tests

npm test

The tests use a database called connect-mongo-test.

Showcase

Open source projects and production apps using connect-mongo. Feel free to add yours in a pull request.

Builder Book: Open source web app to write and host documentation or sell books. Built with React, Material-UI, Next, Express, Mongoose, MongoDB.

License

The MIT License

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