Detecting relevant paths in the request.

DetectRelevantPaths.js

const path = require('path');

exports.handler = (event, context, callback) => {
  const { request, config } = event.Records[0].cf;

  let originalUri = request.uri;
  const parsedPath = path.parse(originalUri);

  if (parsedPath.ext === '') {
    // Every request that does not have an extension should be a route in our
    // SPA. We can fetch index.html here and add proper metadata. All other 
    // requests with proper extensions should be redirected to actual resource
    // in S3.
  } else {
    return callback(null, request); // Do not modify request.
  }
};