koa-session

Simple cookie-based session middleware for Koa.

Installation

$ npm install koa-session

Example

View counter example:

var session = require('koa-session');
var koa = require('koa');
var app = koa();

app.keys = ['some secret hurr'];

var CONFIG = {
  key: 'koa:sess', /** (string) cookie key (default is koa:sess) */
  maxAge: 86400000, /** (number) maxAge in ms (default is 1 days) */
  overwrite: true, /** (boolean) can overwrite or not (default true) */
  httpOnly: true, /** (boolean) httpOnly or not (default true) */
  signed: true, /** (boolean) signed or not (default true) */
};
app.use(session(CONFIG, app));
// or if you prefer all default config, just use => app.use(session(app));

app.use(function *(){
  // ignore favicon
  if (this.path === '/favicon.ico') return;

  var n = this.session.views || 0;
  this.session.views = ++n;
  this.body = n + ' views';
})

app.listen(3000);
console.log('listening on port 3000');

For Koa 2, use koa-convert to convert the session middleware :

const koa = require('koa');
const session = require('koa-session')
const convert = require('koa-convert');

const app = new koa();
app.use(convert(session(app)));

// codes

API

Options

The cookie name is controlled by the key option, which defaults to "koa:sess". All other options are passed to ctx.cookies.get() and ctx.cookies.set() allowing you to control security, domain, path, and signing among other settings.

Custom encode/decode Support

Use options.encode and options.decode to customize your own encode/decode methods.

Hooks

• valid(): valid session value before use it
• beforeSave(): hook before save session

External Session Stores

Session will store in cookie by default, but it has some disadvantages:

• Session stored in client side unencrypted.
• Browser cookie always have length limit.

You can store the session content in external stores(redis, mongodb or other DBs) by pass options.store with three methods(need to be generator function or async function):

• get(key): get session object by key
• set(key, sess, maxAge): set session object for key, with a maxAge (in ms)
• destroy(key): destroy session for key

Once you passed options.store, session is strong dependent on your external store, you can't access session if your external store is down. Use external session stores only if necessary, avoid use session as a cache, keep session lean and stored by cookie!

Session#isNew

Returns true if the session is new.

if (this.session.isNew) {
  // user has not logged in
} else {
  // user has already logged in
}

Session#maxAge

Get cookie's maxAge.

Session#maxAge=

Set cookie's maxAge.

Destroying a session

To destroy a session simply set it to null:

this.session = null;

License

MIT