To put it short: Is it possible to redirect a visitor to a custom URI scheme, or show some content if that scheme is not supported?
My particular use case is that I'm creating a mobile app that registers a custom URI scheme so that users can invite other users to certain actions within the app by sending links via SMS or e-mail.
The links point to my server (running PHP on Apache), and the server redirects the visitors to the proper scheme. This works perfectly as long as that's all the redirect page does, but I'd like to be able to show some content in case the e-mail is opened on a computer or some other device that doesn't have my app installed.
<meta http-equiv="Location" content="myscheme://testing"> tag on the page, but that didn't do anything either.
Some people have suggested using user-agent sniffing to see whether the client is using a mobile or a desktop browser. I am already doing this as well as a preliminary check, but it still leaves the possibility the link is opened on a mobile device that doesn't have my app installed, and those people would be left with an empty page.
Is there some way to achieve this, or am I out of luck?