Dynamically receive arguments

I'm going over the possibilities to handle a html form submission since directive [mailout](https://caddy.its-em.ma/v1/docs/http.mailout) that used to work perfectly with caddy v1 is not supported in v2 anymore.

Was thinking to simply trigger a .go file when a route is being hit. Is it possible to dynamically receive arguments instead of hard coding them in the Caddyfile?

e.g something like this:
```
// command to execute
"command": "handleform.go",
// command arguments
"args": [$args]
```