chore(analytics) | Improve traffic source retention on cross domain measurements

[cgarrovillo]

What is the change

This aims to mitigate an issue in cross-domain measurements where the original traffic source is not maintained throughout the entire session despite matching client_id/session_id.

I did this by keeping track of the parent documents referrer, which is used by GA4 as the traffic source

How to test

Use this PR on the web-app https://bitbucket.org/showpass/web-app/pull-requests/6734

GIVEN a site with a different domain than showpass

AND an iframe of showpass displayed through the showpass plugin

WHEN you open up the iframe

THEN you should see in network devtools that the referrer for the first /collect call to analytics.google.com is that the referrer is the parent domain.

GIVEN a site with a different domain than showpass

AND an iframe of showpass displayed through the showpass plugin

WHEN you visit the site through google search, or through another domain

AND you open up the iframe

THEN you should see in network devtools that the referrer for the first /collect call to analytics.google.com is that the referrer is the original site you first landed on. For example, exampleA.com → exampleB.com → showpass.com → add to cart, the referrer is exampleA.com.

You can see the field on network devtools /collect call payload under the _dr parameter

[ShannonTJ]

Do you also need to check if referrer !== ""
?

[cgarrovillo]

hmm I think thats covered already by the truthiness check

[ShannonTJ]

Just checking, since we do that check for the cookie up above.

[cgarrovillo]

Hmm cant remember exactly why we did that for the cookie tbh lol but I think theres a reason for cookies..