Simple Stripe Payments with Firebase Cloud Functions

index.js

const functions = require('firebase-functions')
const admin = require('firebase-admin')

admin.initializeApp(functions.config().firebase);

const stripe = require('stripe')(functions.config().stripe.testkey)



exports.stripeCharge = functions.database
                                .ref('/payments/{userId}/{paymentId}')
                                .onWrite(event => {

                                  

  const payment = event.data.val();
  const userId = event.params.userId;
  const paymentId = event.params.paymentId;
  

  // checks if payment exists or if it has already been charged
  if (!payment || payment.charge) return;

  return admin.database()
              .ref(`/users/${userId}`)
              .once('value')
              .then(snapshot => {
                  return snapshot.val();
               })
               .then(customer => {

                 const amount = payment.amount;
                 const idempotency_key = paymentId;  // prevent duplicate charges
                 const source = payment.token.id;
                 const currency = 'usd';
                 const charge = {amount, currency, source};


                 return stripe.charges.create(charge, { idempotency_key });

               })

               .then(charge => {
                   admin.database()
                        .ref(`/payments/${userId}/${paymentId}/charge`)
                        .set(charge)
                  })


});

package.json

{
  "name": "functions",
  "description": "Cloud Functions for Firebase",
  "dependencies": {
    "firebase-admin": "^4.1.2",
    "firebase-functions": "^0.5",
    "stripe": "^4.23.1"
  },
  "private": true
}

Small question, where do you set the keys for stripe?

You set It with the firebase cli by entering firebase functions:config:set stripe.testKey="YOUR STRIPE SECRET KEY" on the command line.

Hey, i have a similar function but when viewing the logs for the function i see that it says cannot read property val of undefined. I'd love some help

Hey, i have a similar function but when viewing the logs for the function i see that it says cannot read property val of undefined. I'd love some help

Were you able to solve this problem? If yes? then how?