so I want to have some DeepLinks on my webpage that fire up a mobile app I created on my mobile device using Unity.
The DeepLinks are constructed in a way:
myapp://view?itm=356723
Now, if my mobile phone has the app installed, it will launch the app and use the information provided by the DeepLink properly. If I do not have the mobile app installed, I'll get a 404.
What I'd like to know: Is there any way to provide a special 404-page that tells the user to download the App with a link from the app-store instead of redirecting to the standard 404-page the webserver provides? For this, I'd like to assume that I run on a recent Apache Webserver and have access to .htaccess and everything else. Even PHP is a given.
I know that there are sophisticated solutions for DeepLinking like branch.io but let's say I want to keep things simple and use this approach.
Thanks for your help!