Rich Social Sharing with CloudFront

index.js

exports.handler = (event, context, callback) => {
  'use strict';
  const request = event.Records[0].cf.request;
  const userAgent = request.headers['user-agent'][0].value;
  
  let prerender = 0;
  // user agent is known social bot
  if (userAgent.match(/baiduspider|twitterbot|facebookexternalhit|googlebot|bingbot|yandex|rogerbot|linkedinbot|embedly|quora link preview|showyoubot|outbrain|pinterest|slackbot|vkShare|W3C_Validator/i)) {
    prerender = 1;
  }
  // rendered page is requested by special query string
  if (request.querystring.match(/_escaped_fragment_/)) {
    prerender = 1;
  }
  // request is coming from prerender.io, so serve original page
  if (userAgent.match(/Prerender/)) {
    prerender = 0;
  }
  // request targets non-html files
  if (request.uri.match(/\.(js|css|xml|less|png|jpg|jpeg|gif|pdf|doc|txt|ico|rss|zip|mp3|rar|exe|wmv|doc|avi|ppt|mpg|mpeg|tif|wav|mov|psd|ai|xls|mp4|m4a|swf|dat|dmg|iso|flv|m4v|torrent|ttf|woff|svg|eot)/i)) {
    prerender = 0;
  }
  
  if (prerender === 1) {
    request.origin = {
      custom: {
        protocol: 'http',
        domainName: 'service.prerender.io',
        port: 80,
        path: '/https://www.example.de',
        sslProtocols: ['TLSv1', 'TLSv1.1'],
        readTimeout: 30,
        keepaliveTimeout: 30,
        customHeaders: {
          'x-prerender-token': [
            {
              "key": "X-Prerender-Token",
              "value": "yourPrerenderIOToken"
            }
          ]
        }
      }
    };
  }
  callback(null, request);
};