sjwt's Introduction

SJWT

A simple Json Web Token module written with minimal footprint in mind. SJWT uses SHA256 for signatures. Injecting custom hash functions is also supported.

Installation

$ npm install -S '@paweljarema/sjwt'

Setup

To create secure tokens, you need to pass a secret to SJWT constructor. It's best to prepare an instance in a separate file and require later:

`jwt.js`

const SJWT = require('@paweljarema/sjwt')
const { appSecret } = require('../config/keys')   // appSecret is just a string

module.exports = new SJWT({ secret: appSecret })

Usage

To create a secure token, do:

const jwt = require('jwt.js')   // jwt.js from previous step
const token = jwt.tokenize(dataObject)

To parse token:

jwt.parse(token)   // returns 'undefined' for invalid tokens

Token expiry date

If you want your tokens to expire with time, you need to implement this yourself:

const TTL = 24 * 60 * 60 * 1000
const data = {
    _id: 'session_id or user_id',
    expires: Date.now() + TTL,
}
const token = jwt.tokenize(data)

To test if token expired:

    const data = jwt.parse(token)
    const tokenIsValid = data && data.expires >= Date.now()

Custom hash function

To use customgit hashing function, provide additional props in constructor, just like we did in setup. Hash function should take a string and return a hashed string:

const SJWT = require('@paweljarema/sjwt')
const { appSecret } = require('../config/keys')
const myHashFunction = require('my-hash-function')
module.exports = new SJWT({
    secret: appSecret,
    hashFunction: myHashFunction,
    hashFunctionName: 'my-hash-function'
})