PubNub functions implementation of Google OAUTH2 w/ Authorization code flow

oath2-authorization-code.js

// https://developers.google.com/actions/identity/oauth2?oauth=code
const kvstore = require('kvstore')
const base64 = require('codec/base64')

const GOOGLE_CLIENT_ID = 'google-client-id'

export default (request, response) => {
  let headersObject = request.headers
  let bodyString = request.body
  let paramsObject = request.params
  let methodString = request.method

  console.log('params', paramsObject)
  const { client_id: clientId, client_secret: clientSecret, grant_type: grantType, code: authorizationCode, refresh_token: refreshToken } = paramsObject
  // Query parameters passed are parsed into the request.params object for you

  // Set the status code - by default it would return 200
  // Set the headers the way you like

  response.status = 200

  if (grantType === 'authorization_code') {
    return kvstore.get(authorizationCode)
      .then(authorizationCodeBody => {
        authorizationCodeBody = JSON.parse(base64.atob(authorizationCode))
        console.log('authcodeBody', authorizationCodeBody)
        if (authorizationCodeBody && Date.now() < authorizationCodeBody.expiresAt && clientId === authorizationCodeBody.clientId) {
          const encryptedEmail = authorizationCodeBody.encryptedEmail
          const refreshTokenBody = JSON.stringify({
            type: 'REFRESH_TOKEN',
            encryptedEmail,
            clientId: GOOGLE_CLIENT_ID,
            expiresAt: null
          })
          const accessTokenBody = JSON.stringify({
            type: 'ACCESS_TOKEN',
            encryptedEmail,
            GOOGLE_CLIENT_ID,
            expiresAt: new Date().setHours(new Date().getHours() + 2)
          })
          const refreshToken = base64.btoa(refreshTokenBody)
          const accessToken = base64.btoa(accessTokenBody)
          return Promise.all([kvstore.set(refreshToken, refreshTokenBody), kvstore.set(accessToken, accessTokenBody)])
            .then(() => {
              return response.send(
                {
                  'token_type': 'Bearer',
                  'access_token': accessToken,
                  'refresh_token': refreshToken,
                  'expires_in': (JSON.parse(accessTokenBody).expiresAt - Date.now()) / 1000
                }
              )
            })
        } else {
          console.log('authCodeBody', authorizationCodeBody, 'clientId', clientId, 'actualId', authorizationCodeBody.clientId, Date.now() < authorizationCodeBody.expiresAt)
          response.status = 400
          return response.send({'error': 'invalid_grant'})
        }
      })
  } else if (grantType === 'refresh_token') {
    return kvstore.get(refreshToken)
      .then(refreshTokenBody => {
        refreshTokenBody = JSON.parse(base64.atob(refreshTokenBody))
        if (refreshTokenBody.type === 'REFRESH_TOKEN' && clientId === refreshTokenBody.clientId) {
          const encryptedEmail = refreshTokenBody.encryptedEmail
          const accessTokenBody = JSON.stringify({
            type: 'ACCESS_TOKEN',
            encryptedEmail,
            clientId: GOOGLE_CLIENT_ID,
            expiresAt: new Date().setHours(new Date().getHours() + 2)
          })
          const accessToken = base64.btoa(accessTokenBody)
          return kvstore.set(accessToken, accessTokenBody)
            .then(() => {
              return response.send({
                'token_type': 'Bearer',
                'access_token': accessToken,
                'expires_in': (JSON.parse(accessTokenBody).expiresAt - Date.now()) / 1000
              })
            })
        } else {
          response.status = 400
          console.log('refreshTokenBody', refreshTokenBody, 'clientId', clientId, 'actualId', refreshTokenBody.clientId, Date.now() < refreshTokenBody.expiresAt)
          return response.send({'error': 'invalid_grant'})
        }
      })
  } else {
    response.status = 400
    return response.send('unknown grant_type')
  }
}