examples: add a Lua example setting user name for a VPN connection

examples/lua/lgi/Makefile.am

@@ -4,4 +4,5 @@ EXTRA_DIST = \
 	list-devices.lua \
 	show-wifi-networks.lua \
 	get-basic-nm-info.lua \
-	get-ips.lua
+	get-ips.lua \
+	change-vpn-username.lua

examples/lua/lgi/change-vpn-username.lua

@@ -0,0 +1,85 @@
+#!/usr/bin/env lua
+-- -*- Mode: Lua; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+-- vim: ft=lua ts=2 sts=2 sw=2 et ai
+--
+-- This program is free software; you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation; either version 2 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License along
+-- with this program; if not, write to the Free Software Foundation, Inc.,
+-- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+--
+-- Copyright 2015 Red Hat, Inc.
+--
+--
+-- This example changes username in a VPN profile.
+-- The example uses libnm library using GObject introspection via Lua lgi module.
+-- Most distribution ship the module as lua-lgi package.
+-- libnm guide:   https://developer.gnome.org/libnm/1.0/
+-- Lua-lgi guide: https://github.com/pavouk/lgi/blob/master/docs/guide.md
+--
+
+local lgi = require 'lgi'
+local NM = lgi.NM
+
+-- mapping from VPN type to username data item
+vpn2username = {
+  openvpn     = "username",
+  vpnc        = "Xauth username",
+  pptp        = "user",
+  l2tp        = "user",
+  openswan    = "leftxauthusername",
+}
+
+---------------------------
+-- Main code starts here --
+---------------------------
+-- parse command-line arguments
+local profile, username, extra = ...
+if (not profile or not username or extra) then
+  print(string.format("Usage: %s <vpn_profile> <username>", arg[0]:gsub(".*/","")))
+  os.exit(1)
+end
+
+-- get client object
+client = NM.Client.new()
+
+-- find the connection profile
+con = client:get_connection_by_id(profile)
+if not con then con = client:get_connection_by_uuid(profile) end
+if not con then con = client:get_connection_by_path(profile) end
+if not con then io.stderr:write(string.format("Profile %s not found.\n", profile)) os.exit(1) end
+
+if not con:is_type(NM.SETTING_VPN_SETTING_NAME) then
+  io.stderr:write(string.format("Profile '%s' is not a VPN.\n", profile))
+  os.exit(1)
+end
+
+-- get VPN setting
+vpn = con:get_setting_vpn()
+service_name = vpn:get_service_type()
+vpn_type = service_name:match(".*%.(.*)")
+
+if not vpn2username[vpn_type] then
+  io.stderr:write(string.format("Unknown VPN type '%s'.\n", vpn_type))
+  os.exit(1)
+end
+
+-- update the username
+vpn:add_data_item(vpn2username[vpn_type], username)
+-- save changes
+ok, errmsg = con:commit_changes(true)
+if not ok then
+  io.stderr:write(string.format("Error in updating connection: %s.\n", errmsg))
+  os.exit(1)
+end
+
+print(string.format("Username updated to '%s'.", username))
+