Save JSON Objects to AWS S3 with Google Recaptcha

This post will show you how to save messages from a public endpoint to your backend using AWS Lambda, AWS S3 and Google Recaptcha.

Wrote the GIST for myself but I had enough requests to share it in a blog post. Copy/paste what you want.

Request from a frontend source

Add this to the frontend index.html (or anywhere a form will be sent from). Replace the _reCAPTCHA_site_key with a real one.

<script src="https://www.google.com/recaptcha/api.js?render=_reCAPTCHA_site_key"></script>
<script>
  grecaptcha.ready(function() {
      grecaptcha.execute('_reCAPTCHA_site_key_', {action: 'homepage'}).then(function(token) {
      ...
      });
  });
</script>

Docs: https://developers.google.com/recaptcha/docs/v3

Backend Setup

Start by creating an AWS Lambda function that has access to add items to S3. Using a node.js/javascript lambda function.

Environment Keys:

• GoogleRecapKey : Get this from https://developers.google.com/recaptcha
• MessageBucket : Create a bucket in AWS S3.
• SnsTopicArn : Create a SNS topic to receive emails or SMS to your phone.

API Gateway Setup

• Create an AWS API Gateway API with a resource form with a method POST.
• Integration type Lambda Function
• Use Lambda Proxy integration: checked
• Select Lambda function