Koa cookie returning `undefined`

Question

After a POST request is sent from the browser to the /generate url in the server, I want to create a string and save it as a cookie. When a GET request is later sent from the browser to the /retrieve url in the server, I want to send that string as a response to the client.

Here is what I tried:

routes.js

const Router = require('koa-router')
const router = new Router()

router.post('/generate', function * () {
  this.cookies.set('generatedString', 'example')
  this.response.body = 'String saved as cookie!'
})

router.get('/retrieve', function * () {
  const cookie = this.cookies.get('generatedString')
  console.log(cookie) // undefined!
  this.response.body = cookie
})

Why does doing this.cookies.get('generatedString') return undefined even though the POST request handler has already run and should have set that cookie? Any help would be appreciated!

---

EDIT: In case it is of importance, I thought it would be worth mentioning that I am using the fetch API to make the POST and GET requests.

Answer 1

In case it is of importance, I thought it would be worth mentioning that I am using the fetch API to make the POST and GET requests.

The fetch API mentions that "By default, fetch won't send any cookies to the server, resulting in unauthenticated requests if the site relies on maintaining a user session."

If you want fetch to send cookies, you will need to add an option to the request you send out called credentials and set it to a value of include.

Example POST request:

const request = {
  method: 'POST',
  credentials: 'include',
  headers: ...,
  body: ...
}

fetch('/generate', request).then(...)

Example GET request:

fetch('/retrieve', { credentials: 'include' }).then(...)