Simple Redirector for ad publishers

Premise

Retail owners publish and push ads that consist of news articles and blogs that talk about their products.

For example - Uber Eats could create an ad with a Forbes article that talks about how great uber eats is.

Problem

Retail owners are unable to track users who have clicked on these ads when the ad content itself is for third party site.

For example - As the owner of Uber Eats I would like to ensure that I know when a user who has clicked on these ads visit my site so I can either target them with better pricing or better offers.

Solution

DIY method (Cheapest Option): Create a CF worker that allows you to drop a cookie along with a redirect so you can track the cookie when a particular user visits your site
Paid Solution(A tad bit expensive): It's possible that Third-Party tools offer the same solution but they usually have a lot more other services that might not be required.

CloudFlare Worker Solution

Three parts to the worker solution

a) Find a query string parameter within the incoming URL. Credits to Emedara for the code snippet

//function to handle the request
async function handleRequest(request) {
  const url = request.url
    // Function to parse query strings
    function getParameterByName(name) {
        name = name.replace(/[\[\]]/g, '\\$&')
        name = name.replace(/\//g, '')
        var regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
            results = regex.exec(url)
        if (!results) return null
        else if (!results[2]) return ''
        else if (results[2]) {
            results[2] = results[2].replace(/\//g, '')
        }
        return decodeURIComponent(results[2].replace(/\+/g, ' '));
    }

b) Find final destination url and campaign cookie you set within the ad CTA url

// Using the function getParameterByName to extract finalurl
var finalURL = getParameterByName('finalurl')
console.log(finalURL)

//conditionally add a campaign cookie you wish to add to the url 
var utmcookie = getParameterByName('utm_camp')
var utmcookiedomain = 'campagincookie='+ utmcookie + '; Domain=redirect.akhil.workers.dev; Max-Age=40000'
console.log(utmcookie)

c) Issue the redirect to the final destination with the set-cookie parameter

//issue the redirect 
return new Response('', {
  status: 302,
  headers: {
    Location: finalURL,
   'Set-Cookie':utmcookiedomain,
  }
 })

Full Code

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

//function to handle the request
async function handleRequest(request) {
  const url = request.url
    // Function to parse query strings
    function getParameterByName(name) {
        name = name.replace(/[\[\]]/g, '\\$&')
        name = name.replace(/\//g, '')
        var regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
            results = regex.exec(url)
        if (!results) return null
        else if (!results[2]) return ''
        else if (results[2]) {
            results[2] = results[2].replace(/\//g, '')
        }
        return decodeURIComponent(results[2].replace(/\+/g, ' '));
    }

    // Using the function getParameterByName to extract finalurl
    var finalURL = getParameterByName('finalurl')
    console.log(finalURL)

//conditionally add a campaign cookie you wish to add to the url 
var utmcookie = getParameterByName('utm_camp')
var utmcookiedomain = 'campagincookie='+ utmcookie + '; Domain=*.akhil.workers.dev; Max-Age=40000'
console.log(utmcookie)
//issue the redirect 
  return new Response('', {
            status: 302,
            headers: {
            Location: finalURL,
            'Set-Cookie':utmcookiedomain,
      }
        })

}

Final Solution

https://redirect.akhil.workers.dev?finalurl=<<Enter Final URL for the arctile>>&utm_camp=<<Enter the cookie you want to set>>

Example Link: https://redirect.akhil.workers.dev?finalurl=https%3A%2F%2Ftimesofindia.indiatimes.com%2Ftrend-tracking%2Fev-startups-crank-up-efforts-as-segments-mood-turns-electric%2Farticleshow%2F70416317.cms&utm_camp=akhilcookie