404 from callbackURL with koa-passport using passport-oauth2 strategy - node.js

Question

I am having trouble understanding why my koa v2 app is 404ing when it receives the callback from my oauth2 provider. I see in the network tab that it is receiving a GET to /oauth/callback with a code query parameter. My routes definitely exist because if I open the page in the browser myself it 500s with an error:
TokenError: The provided authorization grant is invalid, expired,
revoked, does not match the redirection URI used in the authorization
request, or was issued to another client.
Here is my app so far, following the koa-passport-example:
const Koa = require('koa')
const app = new Koa()
// trust proxy
app.proxy = true
// sessions
const convert = require('koa-convert')
const session = require('koa-generic-session')
app.keys = ['your-session-secret']
app.use(convert(session()))
// body parser
const bodyParser = require('koa-bodyparser')
app.use(bodyParser())
// authentication
require('./authn')
const passport = require('koa-passport')
app.use(passport.initialize())
app.use(passport.session())
// routes
const fs = require('fs')
const route = require('koa-route')
app.use(route.get('/logout', function(ctx) {
ctx.logout()
ctx.redirect('/login')
}))
app.use(route.get('/login',
passport.authenticate('oauth2')
))
app.use(route.get('/oauth/callback',
passport.authenticate('oauth2', {
failureRedirect: '/login',
successRedirect: '/'
})
))
// Require authentication for now
app.use(function(ctx, next) {
console.log('auth check', ctx.isAuthenticated())
if (ctx.isAuthenticated()) {
return next()
} else {
ctx.redirect('/login')
}
})
app.use(route.get('/', function(ctx) {
ctx.type = 'html'
ctx.body = fs.createReadStream('views/app.html')
const { token } = ctx.state
const authed = ctx.isAuthenticated()
if (authed) {
console.log('token', token)
}
}))
// start server
const port = process.env.PORT || 3000
app.listen(port, () => console.log('Server listening on', port))
And the authn.js file:
import passport from 'koa-passport'
const user = { id: 1, username: 'dmarr#foo.com' }
passport.serializeUser(function(user, done) {
done(null, user.id)
})
passport.deserializeUser(function(id, done) {
done(null, user)
})
var OAuth2Strategy = require('passport-oauth2').Strategy
passport.use(new OAuth2Strategy({
authorizationURL: 'redacted',
tokenURL: 'https://redacted/token',
clientID: 'redacted',
clientSecret: 'redacted',
callbackURL: "http://localhost:8080/oauth/callback"
},
function(accessToken, refreshToken, profile, done) {
console.log('authed with oauth')
console.log('token', accessToken)
console.log('refresh token', refreshToken)
done(null, user)
// User.findOrCreate({ exampleId: profile.id }, function (err, user) {
// return done(err, user);
// });
// console.log(accessToken)
}
));
Thank you for any help

Answer 1

Well this seems to be working after all. I did have a typo which appears to have been the issue. Keeping the above in case anyone else needs help with oauth2 and koa and passport.
Edit: It turns out I can't seem to access the modified user from the authenticate callback. For example:
function(accessToken, refreshToken, profile, done) {
user.accessToken = accessToken
done(null, user)
})
and in my route handler
const { passport } = ctx.session
const user = passport.user
// user.accessToken is undefined because session.passport.user is the serialized one