HTTP API for local DNS records in unbound(8)

dns

#!/bin/sh -eu

DOMAIN=lointa.in
JOURNAL=/srv/dns/$DOMAIN

fail() { echo "Status: $1"; echo "Content-Type: text/plain"; echo; echo "$REQUEST_METHOD"; exit; }

if [ -z "$PATH_INFO" ]; then
	echo "Status: 308 Permanent Redirect"
	echo "Content-Length: 0";
	echo "Location: $SCRIPT_NAME/"
	echo
	exit
elif [ "x$PATH_INFO" = x/ ]; then
	if [ "x$REQUEST_METHOD" != xGET ]; then fail 405; fi
	echo 'Content-Type: text/json'
	echo 'Link: </dns.jsonld>; rel="http://www.w3.org/ns/json-ld#context"; type="text/ld+json"'
	echo
	sep=[
	for file in "$JOURNAL"/*; do
		printf '%s "%s"\n' "$sep" "$(basename "$file")"; sep=,
	done
	echo ]
	exit
elif echo "$PATH_INFO" | grep -Eq '^/[a-zA-Z0-9-]{1,63}'; then :; else
	fail 404
fi

name=$(echo "$PATH_INFO" | cut -c 2- | tr A-Z a-z)
if [ "x$REQUEST_METHOD" = xGET ]; then
	echo "Content-Type: text/json; charset=utf-8"
	echo
	cat "$JOURNAL/$name"
elif [ "x$REQUEST_METHOD" = xPUT ]; then
	if [ x"$CONTENT_TYPE" = xtext/json ] \
	|| [ x"$CONTENT_TYPE" = xapplication/json ]; then :; else fail 415; fi

	data=$(mktemp); trap "rm -f '$data'" EXIT
	if jq -c . >"$data" 2>&1; then :; else fail 400; fi
	if
		unbound-control local_data \
		"$name.$DOMAIN. 300 A $(cat "$data" | jq -r .address)" \
		>/dev/null
	then :; else fail 400; fi
	mv "$data" "$JOURNAL/$name"

	echo "Status: 200"
	echo "Content-Length: 0"
	echo
elif [ "x$REQUEST_METHOD" = xDELETE ]; then
	if [ -f "$JOURNAL/$name" ]; then :; else fail 404; fi
	if [ -w "$JOURNAL/$name" ]; then :; else fail 403; fi
	rm "$JOURNAL/$name"
	unbound-control local_data_remove "$name.$DOMAIN" >/dev/null

	echo "Status: 200"
	echo "Content-Length: 0"
	echo
else
	fail 405
fi