Koa OAuth Server 
Complete, compliant and well tested module for implementing an OAuth2 Server/Provider with koa in node.js.
This is the koa wrapper for oauth2-server.
Installation
$ npm install koa-oauth-server
Quick Start
The module provides two middlewares - one for granting tokens and another to authorise them. koa-oauth-server and, consequently oauth2-server, expect the request body to be parsed already.
The following example uses koa-bodyparser but you may opt for an alternative library.
var koa = require('koa');
var bodyparser = require('koa-bodyparser');
var oauthserver = require('koa-oauth-server');
var app = koa();
app.oauth = oauthserver({
model: {}, // See https://github.com/thomseddon/node-oauth2-server for specification
grants: ['password'],
debug: true
});
app.use(bodyparser());
app.use(app.oauth.authorise());
app.use(function *(next) {
this.body = 'Secret area';
yield next;
});
app.listen(3000);Using koa-router with koa-mount
If you wish to integrate with koa-router using koa-mount, you may do so by combining them to mount a specific prefix for oauth operations:
var Router = require('koa-router');
var bodyparser = require('koa-bodyparser');
var koa = require('koa');
var model = require('koa-oauth-server/node_modules/oauth2-server/examples/memory/model');
var mount = require('koa-mount');
var oauthserver = require('koa-oauth-server');
// Create a new koa app.
var app = koa();
// Create a router for oauth.
var router = new Router();
// Enable body parsing.
app.use(bodyparser());
// See https://github.com/thomseddon/node-oauth2-server for specification.
app.oauth = oauthserver({
model: model,
grants: ['password'],
debug: true
});
// Mount `oauth2` route prefix.
app.use(mount('/oauth2', router.middleware()));
// Register `/token` POST path on oauth router (i.e. `/oauth2/token`).
router.post('/token', app.oauth.grant());
// Start koa server.
app.listen(3000);Then attempt to be granted a new oauth token:
curl -XPOST -d 'username=thomseddon&password=nightworld&grant_type=password&client_id=thom&client_secret=nightworld' http://localhost:3000/oauth2/token