Add. Event handler to support MWI. (#1720)

* Add. Event handler to support MWI.

* Fix. store cache only when get data from memcache

* Change. Use UUID as PID.

resources/install/scripts/app/voicemail/resources/scripts/mwi_subscribe.lua

@@ -0,0 +1,132 @@
+require "resources.functions.config"
+require "resources.functions.split"
+
+local log           = require "resources.functions.log".mwi_subscribe
+local file          = require "resources.functions.file"
+local Database      = require "resources.functions.database"
+local ievents       = require "resources.functions.ievents"
+local IntervalTimer = require "resources.functions.interval_timer"
+local cache         = require "resources.functions.cache"
+local api           = require "resources.functions.api"
+
+local vm_to_uuid_sql = [[SELECT v.voicemail_uuid
+FROM v_voicemails as v inner join v_domains as d on v.domain_uuid = d.domain_uuid
+WHERE v.voicemail_id = '%s' and d.domain_name = '%s']]
+
+local vm_messages_sql = [[SELECT
+( SELECT count(*)
+  FROM v_voicemail_messages
+  WHERE voicemail_uuid = %s
+  AND (message_status is null or message_status = '')
+) as new_messages,
+
+( SELECT count(*)
+  FROM v_voicemail_messages
+  WHERE voicemail_uuid = %s
+  AND message_status = 'saved'
+) as saved_messages
+]]
+
+local function vm_message_count(account, use_cache)
+	local id, domain_name = split_first(account, '@', true)
+	if not domain_name then return end
+
+	-- FusionPBX support only numeric voicemail id
+	if not tonumber(id) then
+		log.warningf('non numeric voicemail id: %s', id)
+		return
+	end
+
+	local dbh = Database.new('system')
+	if not dbh then return end
+
+	local uuid
+	if use_cache and cache.support() then
+		local uuid = cache.get('voicemail_uuid:' .. account)
+		if not uuid then
+			local sql = string.format(vm_to_uuid_sql,
+				dbh:escape(id), dbh:escape(domain_name)
+			)
+			uuid = dbh:first_value(sql)
+
+			if uuid and #uuid > 0 then
+				cache.set('voicemail_uuid:' .. account, uuid, 3600)
+			end
+		end
+	end
+
+	local sql 
+	if uuid and #uuid > 0 then
+		sql = string.format(vm_messages_sql,
+			dbh:quoted(uuid), dbh:quoted(uuid)
+		)
+	else
+		local uuid_sql = '(' .. string.format(vm_to_uuid_sql,
+			dbh:escape(id), dbh:escape(domain_name)
+		) .. ')'
+
+		sql = string.format(vm_messages_sql,
+			uuid_sql, uuid_sql
+		)
+	end
+
+	local row = sql and dbh:first_row(sql)
+
+	dbh:release()
+
+	if not row then return end
+
+	return row.new_messages, row.saved_messages
+end
+
+local function mwi_notify(account, new_messages, saved_messages)
+	local event = freeswitch.Event("message_waiting")
+	if (new_messages == "0") then
+		event:addHeader("MWI-Messages-Waiting", "no")
+	else
+		event:addHeader("MWI-Messages-Waiting", "yes")
+	end
+	event:addHeader("MWI-Message-Account", "sip:" .. account)
+	event:addHeader("MWI-Voice-Message", new_messages.."/"..saved_messages.." (0/0)")
+	return event:fire()
+end
+
+local sleep    = 60000
+local pid_file = scripts_dir .. "/run/mwi_subscribe.tmp"
+local pid = api:execute("create_uuid") or tostring(api:getTime())
+file.write(pid_file, pid)
+
+log.notice("start");
+
+local timer = IntervalTimer.new(sleep):start()
+
+for event in ievents("MESSAGE_QUERY", 1, timer:rest()) do
+	if (not event) or (timer:rest() < 1000) then
+		if not file.exists(pid_file) then break end
+		local stored = file.read(pid_file)
+		if stored and stored ~= pid then break end
+		timer:restart()
+	end
+
+	if event then
+		-- log.notice("event:" .. event:serialize("xml"));
+		local account_header = event:getHeader('Message-Account')
+		if account_header then
+			local proto, account = split_first(account_header, ':', true)
+
+			if (not account) or (proto ~= 'sip' and proto ~= 'sips') then
+				log.warningf("invalid format for voicemail id: %s", account_header)
+			else
+				local new_messages, saved_messages = vm_message_count(account)
+				if not new_messages then
+					log.warningf('can not find voicemail: %s', account)
+				else
+					log.noticef('voicemail %s has %s/%s messages', account, new_messages, saved_messages)
+					mwi_notify(account, new_messages, saved_messages)
+				end
+			end
+		end
+	end
+end
+
+log.notice("stop")