Cloudflare Worker Googlebot Tracking

worker.js

const analyticsId = 'UA-xxxxxxxxx-x'

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event))
})

/**
 * Check request object for Googlebot UA to send tracking data
 * @param {Event} event
 */
async function handleRequest(event) {

  const request = event.request
  const ua = request.headers.get('user-agent')
  let botName;

  
  // If Googlebot then track hit in Analytics
  if ((botName = ua.match(/[^\s]+\-Google[^\s;]*|Googlebot[^\s;]*/g))) {
    const response = await fetch(request)
    event.waitUntil(analyticsHit(
      {
        uip: request.headers.get('CF-Connecting-IP'),
        dl: request.url,
        cd1: response.status,
        cd2: botName[0],
        cd3: request.method,
        cd4: Math.round(+new Date() / 1000.0)
      }
    ))
    return response
  }
  
  // or just return the original content
  return fetch(request)

}

/**
 * Send bot tracking data using Analytics Measurement Protocol
 * @param {Object} tracking
 */
function analyticsHit(tracking) {
  let payload = '?v=1&t=pageview&tid='+analyticsId
  for(var key in tracking) {
    payload += '&'+key+'='+tracking[key]
  }
  payload += '&cid='+[Math.round(Math.random() * 2147483647),Math.round(+new Date() / 1000.0)].join('.')
  return fetch(encodeURI('https://www.google-analytics.com/collect'+payload))
}