I have an MP3 in Dropbox that I am able to force browsers to download rather than handle natively, with the exception of Safari on iOS. In this case, a straight link on my website to the file opens the Dropbox mobile site with the file showing this:
https://i.sstatic.net/HRER9.jpg
The Download button in the center just opens the MP3 via QuickTime within Safari, while the button on the top right of the page opens another screen that offers "Direct Download" and "Add to my Dropbox". "Direct Download" plays the MP3 within Safari, while "Add to my Dropbox" opens a sign-in page. This is not only inconvenient (why bother havign native apps if Safari won't offer links to them?) but also frustrating for the end user. Not everyone uses Dropbox, and of those who do, most probably aren't inclined to log in via Safari when they already have the app.
What I'm looking for is some way to force mobile Safari to show the "Open In..." menu (best solution) or at the very least, for Dropbox users, to show the "Open in Dropbox" button that appears when Safari can't handle the file natively. The Dropbox app as well as other cloud storage apps are registered in iOS to handle MP3s. When users open PDFs in Safari they are given the choice to open in other apps as well, so there should be no reason that Safari can't do the same with MP3s.
Safari on iOS will not show an "Open in" option for mp3 files, so what you are asking may not be possible.
If you want to load the file directly (bypassing the Dropbox webpage), in the Dropbox link change www to dl. On top of that, normally if you add ?dl=1 to the end of the url it will force it to download. However, you will see that in iOS Safari it behaves the same way as if you just changed the "www" and does not allow you to send it to another app.
