Doesn't come with the BTT Module, s it necessary in this case?
[The latest link you provided (fileinputtest)]
I see, if no input continue
[The latest link you provided (fileinputtest)]
maybe something went wrong when copying the link, attaching directly here
fileinputtest.shortcut (22.4 KB)
Now it works when I click,
But when I drag, it shows the txt File I showed before
It might ask once showing the content of the input, after you press "always allow" it will not ask again
I think It works now,
Are the if Input contains "{" Necessary ?
I didn't have it in my shortcut and it works fine. [Apart from asking for files when I dragged a file to the button]
you could also check whether the input length is bigger than 0 (I didn't immediately see how to do so), it just needs to differentiate between not getting an input and getting the json from BTT. The json always contains {, so I'm checking for that
Yep, it will receive text from BTT (although I don't know whether that makes a difference). This is to work around the temp folder issue.
Your changes look good! I think it can be further simplified but as a proof of concept it's now pretty ok.
I don't have the option to choose Contains as you did in the input shortcut.
Copied it from your shortcut, probably a Shortcuts Bug!
This appears if you select the shortcut input to be text:
I don't know why it doesn't do that automatically
Won't let me select it 
It's a bug
Still have the same problem, it prompts me to select a file, although I dragged a file into it.
Does it register a click while I'm dragging the file?
When I click:
Prompts me to select a file, I select it nothing happens, shows another file select window, I select the file and it processes it.
When I drag:
It processes the file I dragged.
Prompts a file select, i select it does nothing
Second file select, It processes it.
It doesn't here, I added some check to prevent an additional click. Is this now with checking for { or without?
maybe a timing thing, I'll increase the click block (after drop) time a little bit
But there's still the Double File select prompt.
The first one does nothing. (By BTT)
Second one by Shortcuts
I think when the button is clicked, it automatically asks for a file [BTT], And We already added a file select in the shortcut, that's why it does nothing with the first selected file.
File selection should either be in BTT in the Button, Or in the shortcut.
Basically the drop zone will be a drop zone ofc, and A simple button to run the shortcut.
Or it can be a drop zone and a file selector (I think this option is better, allows for direct BTT integration and Shortcuts integration at the same time)
I don't think it automatically ask for a file, only the "Select Files" action asks for a file. BTT never does.
It seems like the double prompt is caused by having "Select Multiple" active here, but this doesn't really make sense. Seems like a Shortcuts bug on first glimpse
It's not Shortcuts, tried the Shortcut directly, It works as intended.
With Select Multiple checked!
BTT doesn't have any code to show a file selection menu here 
Maybe for some reason the shortcut is triggered twice, I'll check that
This makes sense, the drop zone button registering the down click and up click maybe 
But again, the first file selection does nothing