docs: update with links to standard and address examples/userinfo review

README.md

@@ -367,7 +367,13 @@ fastify.googleOAuth2.revokeAllToken(currentAccessToken, undefined, (err) => {
 - `userinfo(tokenOrTokenSet)`: A function to retrieve userinfo data from Authorization Provider. Both token (as object) or `access_token` string value can be passed.
 
 Important note:
-Userinfo will only work when `discovery` option is used. For a statically configured plugin, you need to make a HTTP call yourself.
+Userinfo will only work when `discovery` option is used and such endpoint is advertised by identity provider. 
+
+For a statically configured plugin, you need to make a HTTP call yourself.
+
+See more on OIDC standard definition for [Userinfo endpoint](https://openid.net/specs/openid-connect-core-1_0.html#UserInfo)
+
+See more on `userinfo_endpoint` property in [OIDC Discovery Metadata](https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderMetadata) standard definition.
 
 ```js
 fastify.googleOAuth2.userinfo(currentAccessToken, (err, userinfo) => {

examples/userinfo.js

@@ -40,28 +40,16 @@ fastify.register(oauthPlugin, {
 // using async/await (promises API) ->
 // 1. simple one with async
 fastify.get('/interaction/callback/google', async function (request, reply) {
-  try {
-    const tokenResponse = await this.googleOAuth2.getAccessTokenFromAuthorizationCodeFlow(request, reply)
-    const userinfo = await this.googleOAuth2.userinfo(tokenResponse.token /* or tokenResponse.token.access_token */)
-    reply.send(userinfo)
-  } catch (error) {
-    // you want to handle error here better
-    console.error(error)
-    reply.send(error.message)
-  }
+  const tokenResponse = await this.googleOAuth2.getAccessTokenFromAuthorizationCodeFlow(request, reply)
+  const userinfo = await this.googleOAuth2.userinfo(tokenResponse.token /* or tokenResponse.token.access_token */)
+  return userinfo
 })
 
 // 2. custom params one with async
 // fastify.get('/interaction/callback/google', { method: 'GET', params: { /* custom parameters to be added */ } }, async function (request, reply) {
-//   try {
-//     const tokenResponse = await this.googleOAuth2.getAccessTokenFromAuthorizationCodeFlow(request, reply)
-//     const userinfo = await this.googleOAuth2.userinfo(tokenResponse.token /* or tokenResponse.token.access_token */)
-//     reply.send(userinfo)
-//   } catch (error) {
-//     // you want to handle error here better
-//     console.error(error)
-//     reply.send(error.message)
-//   }
+//   const tokenResponse = await this.googleOAuth2.getAccessTokenFromAuthorizationCodeFlow(request, reply)
+//   const userinfo = await this.googleOAuth2.userinfo(tokenResponse.token /* or tokenResponse.token.access_token */)
+//   return userinfo
 // })
 
 // OR with a callback API