Cloudflare service worker to redirect to country subdirectories

worker.js

//Based on https://community.cloudflare.com/t/geoip-redirection-worker/14414

//This assumes you have region-specific sites set up like so

//www.company.com - global landing page where this worker runs
//www.company.com/us/
//www.company.com/au/

//in our case we are only changing paths/dubdirectories, not domains. Map country codes to subdirectories.

 var redirects = {
  'US' : 'us',
  'AU' : 'au'
};

//user agents containing any of these strings don't get redirected
var bypass_ua = ['googlebot','bing'];

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


function byPass(request){

  var length = bypass_ua.length;
  for(var i = 0; i < length; i++) {
      if(request.headers.get('user-agent') && request.headers.get('user-agent').includes(bypass_ua[i])) { 
          return true;
      }
      //any other conditions where you want to bypass redirects should return true here
  }
  return false;
  
}

function mapCountry(country_code){

  if(country_code in redirects) {
    return redirects[country_code];
  }
  return '';

}


/**
 * Fetch and log a given request object
 * @param {Request} request
 */
async function Redirect(request) {
  var url = new URL(request.url);

  correctPath = mapCountry(request.headers.get('CF-IPCountry'));
    
  if(byPass(request) || correctPath == ''){ //nothing to do
    console.log('no redirect');
    const response = await fetch(request)
    return response
  }
  
  //check we are on the global landing page (/) and have somewhere else to go
  if (correctPath != '' && url.pathname == '/'){
    url.pathname = '/' + correctPath;
    console.log('redirecting to '+url.href);
    return new Response('', {
        status: 301,
        headers: {
          'Location': url.href
        }
      })
  }
  
  //fallback
  console.log('no redirect');
  const response = await fetch(request)
  return response
}