Add. BLF indication for call forward. (#2664)

* Add. BLF indication for call forward.

To display general status of CallForward use blf like `forward+<extension>`
To display status for specific phone number use blf like `forward+<extension>/<number>`

* Fix. Escape variable in regex expression.

* Fix. Sync DND and CF blf.

* Add. `blf_subscribe` service which can handle all custom subscriptions.

To run for specific protocol it possible run as `luarun blf_subscribe.lua <PROTO>`

resources/install/scripts/resources/functions/basic_event_service.lua

@@ -0,0 +1,60 @@
+require "resources.functions.config"
+
+local EventConsumer = require "resources.functions.event_consumer".EventConsumer
+
+local function class(base)
+	local t = base and setmetatable({}, base) or {}
+	t.__index = t
+	t.__class = t
+	t.__base  = base
+
+	function t.new(...)
+		local o = setmetatable({}, t)
+		if o.__init then
+			if t == ... then -- we call as Class:new()
+				return o:__init(select(2, ...))
+			else             -- we call as Class.new()
+				return o:__init(...)
+			end
+		end
+		return o
+	end
+
+	return t
+end
+
+local BasicEventService = class(EventConsumer) do
+
+function BasicEventService:__init(log, service_name, timeout)
+	local pid_file = scripts_dir .. "/run/" .. service_name .. ".tmp"
+
+	self = BasicEventService.__base.__init(self, pid_file, timeout)
+
+	-- FS shutdown
+	self:bind("SHUTDOWN", function(self, name, event)
+		log.notice("shutdown")
+		return self:stop()
+	end)
+
+	-- Control commands from FusionPBX
+	self:bind("CUSTOM::fusion::service::control", function(self, name, event)
+		if service_name ~= event:getHeader('service-name') then return end
+
+		local command = event:getHeader('service-command')
+		if command == "stop" then
+			log.notice("get stop command")
+			return self:stop()
+		end
+
+		log.warningf('Unknown service command: %s', command or '<NONE>')
+	end)
+
+	return self 
+end
+
+end
+
+return {
+	BasicEventService = BasicEventService;
+	new = BasicEventService.new;
+}