p5.js-web-editor/server/controllers/aws.controller.js

import uuid from 'node-uuid';
import policy from 's3-policy';

function getExtension(filename) {
  const i = filename.lastIndexOf('.');
  return (i < 0) ? '' : filename.substr(i);
}

export function signS3(req, res) {
  const fileExtension = getExtension(req.body.name);
  const filename = uuid.v4() + fileExtension;
  const acl = 'public-read';
  const p = policy({
    acl,
    secret: process.env.AWS_SECRET_KEY,
    length: 5000000, // in bytes?
    bucket: process.env.S3_BUCKET,
    key: filename,
    expires: new Date(Date.now() + 60000),
  });
  const result = {
    AWSAccessKeyId: process.env.AWS_ACCESS_KEY,
    key: filename,
    policy: p.policy,
    signature: p.signature
  };
  return res.json(result);
}