Add REST endpoint for name resolution

scripts/lua/rest/v1/get/dns/resolve.lua

@@ -0,0 +1,43 @@
+--
+-- (C) 2013-20 - ntop.org
+--
+
+dirs = ntop.getDirs()
+package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path
+
+require "lua_utils"
+local json = require ("dkjson")
+local rest_utils = require("rest_utils")
+
+--
+-- Resolve a name
+-- Example: curl -u admin:admin -d '{"hostname" : "www.google.com"}' http://localhost:3000/lua/rest/v1/get/dns/resolve.lua
+--
+-- NOTE: in case of invalid login, no error is returned but redirected to login
+--
+
+sendHTTPHeader('application/json')
+
+local rc = rest_utils.consts_ok
+local res = {}
+
+local hostname = _GET["hostname"]
+
+if isEmptyString(hostname) then
+   print(rest_utils.rc(rest_utils.consts_invalid_args))
+   return
+end
+
+local resolved = ntop.resolveHost(hostname, true --[[ IPv4 --]])
+if not resolved then
+   resolved = ntop.resolveHost(hostname, false --[[ IPv6 --]])
+end
+
+if not resolved then
+   print(rest_utils.rc(rest_utils.consts_resolution_failed))
+   return
+end
+
+res = resolved
+
+print(rest_utils.rc(rc, res))