Caddyfile

{
	nats {
		url 127.0.0.1:4222
		clientName "My Caddy Server"

		# listens to "datausa.[drilldowns].[measures]" -> calls internal URL
		# nats req "datausa.Nation.Population" ""
		subscribe datausa.> GET http://127.0.0.1:8888/datausa/{nats.request.subject.asUriPath.1}/{nats.request.subject.asUriPath.2}
	}
}

http://127.0.0.1:8888 {
	# internal URL: "/datausa/[drilldowns]/[measures]"
	handle /datausa/* {

		# Reference for placeholders: https://caddyserver.com/docs/json/apps/http/#docs
		rewrite * /api/data?drilldowns={http.request.uri.path.1}&measures={http.request.uri.path.2}

		reverse_proxy https://datausa.io {
			header_up Host {upstream_hostport}
		}
	}

	route /weather/* {
		nats_request cli.weather.{http.request.uri.path.1}
	}
}