alexbenic / next-session

Simple promise-based session middleware for Next.js, micro, Express, and more

next-session

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

Installation

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

Usage

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

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

next-session has several named exports:

• session to be used as a Connect/Express middleware. (Use next-connect if used in Next.js)
• withSession to be used as HOC in Page Components or API Routes wrapper (and several others).
• applySession, to manually initialize next-session by providing req and res.

Use one of them to work with next-session. Can also be used in other frameworks in the same manner as long as they have (req, res) handler signature.

Warning The default session store, MemoryStore, should not be used in production since it does not persist nor work in Serverless.

API Routes

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

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

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

{ session }

import { session } from 'next-session';
import nextConnect from 'next-connect';

const handler = nextConnect()
  .use(session({ ...options }))
  .all(() => {
    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).`
    );
  })

export default handler;

{ withSession }

import { withSession } from 'next-session';

function handler(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).`
  );
}
export default withSession(handler, options);

{ applySession }

import { applySession } from 'next-session';

export default async function handler(req, res) {
  await applySession(req, res, options);
  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).`
  );
}

Pages

next-session does not work in Custom App since it leads to deoptimization.

{ withSession } (getInitialProps)

This will be deprecated in the next major release!

next@>9.3.0 recommends using getServerSideProps instead of getInitialProps. Also, it is not reliable since req or req.session is only available on server only

import { withSession } from 'next-session';

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

Page.getInitialProps = ({ req }) => {
  let views;
  if (typeof window === 'undefined') {
    // req.session is only available on server-side.
    req.session.views = req.session.views ? req.session.views + 1 : 1;
    views = req.session.views;
  }
  // WARNING: On client-side routing, neither req nor req.session is available.
  return { views };
};

export default withSession(Page, options);

{ applySession } (getServerSideProps)

import { applySession } from 'next-session';

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 }) {
  await applySession(req, res, options);
  req.session.views = req.session.views ? req.session.views + 1 : 1;
  return {
    props: {
      views: req.session.views
    }
  }
}

Options

Regardless of the above approaches, to avoid bugs, you want to reuse the same options to in every route. For example:

// Define the option only once
// foo/bar/session.js
export const options = { ...someOptions };

// Always import it at other places
// pages/index.js
import { options } from 'foo/bar/session';
/* ... */
export default withSession(Page, options);
// pages/api/index.js
import { options } from 'foo/bar/session';
/* ... */
await applySession(req, res, options);

next-session accepts the properties below.

options	description	default
name	The name of the cookie to be read from the request and set to the response.	sid
store	The session store instance to be used.	MemoryStore
genid	The function that generates a string for a new session ID.	nanoid
encode	Transforms session ID before setting cookie. It takes the raw session ID and returns the decoded/decrypted session ID.	undefined
decode	Transforms session ID back while getting from cookie. It should return the encoded/encrypted session ID	undefined
touchAfter	Only touch (extend session lifetime despite no modification) after an amount of time to decrease database load. Setting the value to -1 will disable touch().	0 (Touch every time)
rolling	Extends the life time of the cookie in the browser if the session is touched. This respects touchAfter.	false
autoCommit	Automatically commit session. Disable this if you want to manually session.commit()	true
cookie.secure	Specifies the boolean value for the Secure Set-Cookie attribute.	false
cookie.httpOnly	Specifies the boolean value for the httpOnly Set-Cookie attribute.	true
cookie.path	Specifies the value for the Path Set-Cookie attribute.	/
cookie.domain	Specifies the value for the Domain Set-Cookie attribute.	unset
cookie.sameSite	Specifies the value for the SameSite Set-Cookie attribute.	unset
cookie.maxAge	(in seconds) Specifies the value for the Max-Age Set-Cookie attribute.	unset (Browser session)

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),
});

// async function is also supported

API

req.session

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

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

req.session.destroy()

Destroy to current session and remove it from session store.

if (loggedOut) req.session.destroy();

req.session.commit()

Save the session and set neccessary headers and return Promise. Use this if autoCommit is set to false. It must be called before sending response.

req.session.hello = 'world';
await req.session.commit();
// calling res.end or finishing the resolver after the above

req.session.id

The unique id that associates to the current session.

req.session.isNew

Return true if the session is new.

Session Store

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

Compatibility with Express/Connect stores

To use Express/Connect stores, use expressSession and promisifyStore from next-session.

import { expressSession, promisifyStore } from 'next-session';
const MongoStore = require('connect-mongo')(expressSession);
const options = {
  store: promisifyStore(new MongoStore(options))
}

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 (callbacks are not supported or must be promisified like above).

The store may emit store.emit('disconnect') or store.emit('connect') to inform its readiness. (only works with { session })

Contributing

Please see my contributing.md.

License

MIT