Add GeoIP information to header

My team has been tasked with creating an iRule to just add the Geolocation to the header so that the application teams can store that in a database for future reports. None of us are well versed with iRules and are not sure how to even begin this process. Everything I'm finding on devcentral appears to be redirecting traffic based on GeoIP information. We do not want to affect any traffic, just want to add the information based on the URL they are accessing. Any assistance in getting started would be greatly appreciated. Thank you