next-session

Lightweight promise-based session middleware for Next.js. Also works in micro or Node.js HTTP Server, Express, and more.

Also check out alternatives like next-iron-session. Take a look at nextjs-mongodb-app to see this module in use.

Installation

// NPM
npm install next-session
// Yarn
yarn add next-session

Usage

:point_right: Upgrading from v1.x to v2.x? Please read the release notes here!

:point_right: Upgrading from v2.x to v3.x? Please read the release notes here!

:point_right: Upgrading from v3.x to v4.x? Please read the release notes here!

Warning The default session store (if options?.store is undefined), MemoryStore, DOES NOT work in production or serverless environment. You must use a Session Store.

// ./lib/get-session.js
import nextSession from "next-session";
export const getSession = nextSession(options);

API Routes

import { getSession } from "./lib/get-session.js";

export default function handler(req, res) {
  const session = await getSession(req, res);
  session.views = session.views ? session.views + 1 : 1;
  // Also available under req.session:
  // req.session.views = req.session.views ? req.session.views + 1 : 1;
  res.send(
    `In this session, you have visited this website ${session.views} time(s).`
  );
}

Usage in API Routes may result in API resolved without sending a response. This can be solved by either adding:

import nextSession from "next-session";
const getSession = nextSession();

export default function handler(req, res) {
  const session = await getSession(req, res);
  /* ... */
}

export const config = {
  api: {
    externalResolver: true,
  },
};

...or setting options.autoCommit to false and do await session.commit().

import nextSession from "next-session";
const getSession = nextSession({ autoCommit: false });

export default function handler(req, res) {
  const session = await getSession(req, res);
  /* ... */
  await session.commit();
}

getServerSideProps

import { getSession } from "./lib/get-session.js";

export default function Page({ views }) {
  return (
    <div>In this session, you have visited this website {views} time(s).</div>
  );
}

export async function getServerSideProps({ req, res }) {
  const session = await getSession(req, res);
  session.views = session.views ? session.views + 1 : 1;
  // Also available under req.session:
  // req.session.views = req.session.views ? req.session.views + 1 : 1;
  return {
    props: {
      views: session.views,
    },
  };
}

Others

express, next-connect

const express = require("express");
const app = express();
app.use(async (req, res, next) => {
  await getSession(req, res); // session is set to req.session
  next();
});
app.get("/", (req, res) => {
  req.session.views = req.session.views ? req.session.views + 1 : 1;
  res.send(
    `In this session, you have visited this website ${req.session.views} time(s).`
  );
});

micro, Vercel Serverless Functions

module.exports = (req, res) => {
  const session = await getSession(req, res);
  res.end(
    `In this session, you have visited this website ${session.views} time(s).`
  );
};

Node.js HTTP Server

const http = require("http");

const server = http.createServer(async (req, res) => {
  const session = await getSession(req, res);
  res.end(`In this session, you have visited this website ${session.views} time(s).`;
});
server.listen(8080);

Options

next-session accepts the properties below.

touchAfter

Touching refers to the extension of session lifetime, both in browser (by modifying Expires attribute in Set-Cookie header) and session store (using its respective method) upon access. This prevents the session from being expired after a while.

In autoCommit mode (which is enabled by default), for optimization, a session is only touched, not saved, if it is not modified. The value of touchAfter allows you to skip touching if the session is still recent, thus, decreasing database load.

encode/decode

You may supply a custom pair of function that encode/decode or encrypt/decrypt the cookie on every request.

// `express-session` signing strategy
const signature = require("cookie-signature");
const secret = "keyboard cat";
session({
  decode: (raw) => signature.unsign(raw.slice(2), secret),
  encode: (sid) => (sid ? "s:" + signature.sign(sid, secret) : null),
});

API

session object

This allows you to set or get a specific value that associates to the current session.

//  Set a value
if (loggedIn) session.user = "John Doe";
//  Get a value
const currentUser = session.user; // "John Doe"

session.touch()

Manually extends the session expiry by maxAge. Note: You must still call session.commit() if autoCommit = false.

session.touch();

If touchAfter is set with a non-negative value, this will be automatically called accordingly.

session.destroy()

Destroy to current session and remove it from session store.

if (loggedOut) await session.destroy();

session.commit()

Save the session and set neccessary headers. Return Promise. It must be called before sending the headers (res.writeHead) or response (res.send, res.end, etc.).

You must call this if autoCommit is set to false.

session.hello = "world";
await session.commit();
// always calling res.end or res.writeHead after the above

session.id

The unique id that associates to the current session.

Session Store

The session store to use for session middleware (see options above).

Implementation

A compatible session store must include three functions: set(sid, session), get(sid), and destroy(sid). The function touch(sid, session) is recommended. All functions must return Promises.

Refer to MemoryStore.

TypeScript: the SessionStore type can be used to aid implementation:

import type { SessionStore } from "next-session";

class CustomStore implements SessionStore {}

Compatibility with Express/Connect stores

Promisify functions

To use Express/Connect stores, you must promisify get, set, destroy, and (if exists) touch methods, possibly using util.promisify.

We include the util promisifyStore in next-session/lib/compat to do just that:

import nextSession from "next-session";
import { promisifyStore } from "next-session/lib/compat";
import SomeConnectStore from "connect-xyz";

const connectStore = new SomeConnectStore();

const getSession = nextSession({
  store: promisifyStore(connectStore),
});

You can use expressSession from next-session/lib/compat if the connect store has the following pattern.

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

// Use `expressSession` from `next-session/lib/compat` as the replacement

import nextSession from "next-session";
import { expressSession, promisifyStore } from "next-session/lib/compat";
import RedisStoreFactory from "connect-redis";
import Redis from "ioredis";

const RedisStore = RedisStoreFactory(expressSession);
export const getSession = nextSession({
  store: promisifyStore(
    new RedisStore({
      client: new Redis(),
    })
  ),
});

Contributing

Please see my contributing.md.

License

MIT