Adds alert/severity/counters.lua REST API endpoints

Addresses #5754

scripts/lua/rest/v2/get/alert/severity/counters.lua

@@ -0,0 +1,56 @@
+--
+-- (C) 2013-21 - ntop.org
+--
+
+local dirs = ntop.getDirs()
+package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path
+package.path = dirs.installdir .. "/scripts/lua/modules/alert_store/?.lua;" .. package.path
+
+local auth = require "auth"
+local rest_utils = require "rest_utils"
+local alert_consts = require "alert_consts"
+local all_alert_store = require "all_alert_store".new()
+
+--
+-- Read alerts count by time
+-- Example: curl -u admin:admin -H "Content-Type: application/json" -d '{"ifid": "1"}' http://localhost:3000/lua/rest/v2/get/alert/severity/counters.lua
+--
+-- NOTE: in case of invalid login, no error is returned but redirected to login
+--
+
+local rc = rest_utils.consts.success.ok
+local ifid = _GET["ifid"]
+
+if not auth.has_capability(auth.capabilities.alerts) then
+   rest_utils.answer(rest_utils.consts.err.not_granted)
+   return
+end
+
+if isEmptyString(ifid) then
+   rc = rest_utils.consts.err.invalid_interface
+   rest_utils.answer(rc)
+   return
+end
+
+interface.select(ifid)
+
+if not auth.has_capability(auth.capabilities.alerts) then
+   rest_utils.answer(rest_utils.consts.err.not_granted)
+   return
+end
+
+local res = all_alert_store:get_counters_by_severity()
+
+local top_alerts = {}
+
+for _, value in ipairs(res) do
+   top_alerts[#top_alerts + 1] = {
+      count = tonumber(value.count),
+      entity_id = tonumber(value.entity_id),
+      entity_label = alert_consts.alertEntityLabel(value.entity_id),
+      alert_id = tonumber(value.alert_id),
+      name = i18n(alert_consts.alertSeverityById(tonumber(value.severity)).i18n_title),
+   }
+end
+
+rest_utils.answer(rc, top_alerts)