index.js

index.js

const functions = require('firebase-functions')
const admin = require('firebase-admin')
const fetch = require('node-fetch')
admin.initializeApp(functions.config().firebase)

// create an authentication endpoint.
// calls our backend to validate JWT
// if it passes, generate firebase token for the user
module.exports.authenticate = functions.https
.onRequest((req, res) => {
  const { method, query } = req
  
  if (method !== 'GET') 
    return res.status(405).end()


  return makeRequest('/authorize', query)
  .then(uid => admin.auth().createCustomToken(uid))
  .then(token => res.status(200).send({ token }))
})


// listen for new messages and notify our backend
module.exports.onNewMessage = functions.database
.ref(`messages/{roomId}/{messageId}`)
.onWrite(({ data, params }) => {
  const { roomId, messageId } = params
  const payload = data.val()

  return Promise.all([
    admin.database().ref('chats').child(roomId).set(payload),
    makeRequest('/newMessage', payload),
  ])
})


const makeRequest = (path, body) => {
  return fetch('https://api.mybackend.com' + path, {
    method: 'POST',
    body: JSON.stringify(body),
  })
}