Using `userinfo` with googleoauth errors "userinfo can not be used without discovery"

[krishna-404]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Fastify version

4.27.0

Plugin version

7.8.1

Node.js version

20.10.0

Operating system

macOS

Operating system version (i.e. 20.04, 11.3, 10)

12.3.1

Description

Usine userinfo with googleOauth2 gives a throws an error

"userinfo can not be used without discovery"

Google gives a id_token, which it suggests to validate locally & get user details from the same. Documentation from google is below

1. https://developers.google.com/identity/openid-connect/openid-connect#validatinganidtoken
2. https://developers.google.com/identity/openid-connect/openid-connect#discovery

Link to code that reproduces the bug

No response

Expected Behavior

googleOauth2.userinfo(token) should return the user object by locally parsing the jwt.

[mcollina]

Thanks for reporting! Would you like to send a Pull Request to address this issue? Remember to add unit tests.

[byrmsh]

  fastify.register(oauthPlugin, {
    name: 'googleOAuth2',
    scope: ['openid', 'profile', 'email'],
    credentials: {
      client: {
        id: process.env.GOOGLE_OAUTH2_CLIENT_ID!,
        secret: process.env.GOOGLE_OAUTH2_CLIENT_SECRET!,
      },
      // auth: oauthPlugin.GOOGLE_CONFIGURATION,
    },
    startRedirectPath: '/login/google',
    callbackUri: callbackUri('google'),
    discovery: {
      issuer: 'https://accounts.google.com',
    },
  })

It works without any errors if opts.credentials.auth is not provided and opts.discovery is set to 'https://accounts.google.com' like above. I am not sure if this is intended behavior or a bug.

[ogheo]

Looks like it doesn't work if auth is set and discovery not provided, because it goes into userInfoCallbacked fn and there all the logic is written using discovery metadata. As a workaround it can be manually fetched like in this example:

fastify-oauth2/examples/google-with-pkce.js

Line 65 in c3e7efb

const fetchResult = await fetch('https://www.googleapis.com/oauth2/v2/userinfo', {