koa-authz is an authorization middleware for Koa

Usage no npm install needed!

<script type="module">
  import ninja1KoaAuthz from 'https://cdn.skypack.dev/@ninja-1/koa-authz';



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Koa-Authz is an authorization middleware for Koa, it's based on Node-Casbin: https://github.com/casbin/node-casbin.


npm install --save koa-authz

Simple Example

const { Enforcer } = require('casbin')
const Koa = require('koa')
const app = new Koa()
const authz = require('koa-authz')

// response
app.use(async (ctx, next) => {
  const start = new Date()
  await next()
  console.log(new Date() - start)

// use authz middleware
  newEnforcer: async() => {
    // load the casbin model and policy from files, database is also supported.
    const enforcer = await Enforcer.newEnforcer('authz_model.conf', 'authz_policy.csv')
    return enforcer

// reload routes
const router = require('koa-router')({prefix: '/user'})
router.get('/', (ctx) => {
  ctx.body = {name: 'Chalin', age: 26}
router.put('/', (ctx) => {
  ctx.body = {status: 'success'}
app.use(router.routes(), router.allowedMethods())


Use a customized authorizer

This package provides BasicAuthorizer, it uses HTTP Basic Authentication as the authentication method. If you want to use another authentication method like OAuth, you needs to extends BasicAuthorizer as below:

class MyAuthorizer extends BasicAuthorizer {
  // override function
  getUserName () {
    const { username } = this.ctx.state.user
    return username

  newEnforcer: async () => {
    // load the casbin model and policy from files, database is also supported.
    const enforcer = await Enforcer.newEnforcer('examples/authz_model.conf', 'examples/authz_policy.csv')
    return enforcer
  authorizer: (ctx, option) => new MyAuthorizer(ctx, option)

How to control the access

The authorization determines a request based on {subject, object, action}, which means what subject can perform what action on what object. In this plugin, the meanings are:

  1. subject: the logged-on user name
  2. object: the URL path for the web resource like "dataset1/item1"
  3. action: HTTP method like GET, POST, PUT, DELETE, or the high-level actions you defined like "read-file", "write-blog"

For how to write authorization policy and other details, please refer to the Casbin's documentation.

Getting Help


This project is licensed under the Apache 2.0 license.