Detect when a user comes from the website and show them what they were last looking at

Thanks to the latest update to the main site, users will get shown a banner that the website has an app. Clicking on that banner while the app is already installed will not only open the app but also send the full URL as a parameter to the app. 

The URL should be parsed and - if applicable - the user should be shown whatever he was last looking at on the website (e.g. the dealer). 