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--
-- (C) 2013-22 - ntop.org
--
local dirs = ntop.getDirs()
package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path
package.path = dirs.installdir .. "/scripts/lua/modules/datasources/?.lua;" .. package.path
local json = require "dkjson"
local rest_utils = require "rest_utils"
local template = require "resty.template"
-- Import the classes library.
local classes = require "classes"
-- ##############################################
local datasource = classes.class()
-- ##############################################
-- This is the base REST prefix for all the available datasources
datasource.BASE_REST_PREFIX = "/lua/rest/v1/get/datasource/"
-- ##############################################
-- @brief Base class constructor
function datasource:init()
self._dataset_params = {} -- Holds per-dataset params
self._datamodel_instance = nil -- Instance of the datamodel holding data for each dataset
end
-- ##############################################
-- @brief Parses params
-- @param params_table A table with submitted params
-- @return True if parameters parsing is successful, false otherwise
function datasource:read_params(params_table)
if not params_table then
self.parsed_params = nil
return false
end
self.parsed_params = {}
for _, param in pairs(self.meta.params or {}) do
local parsed_param = params_table[param]
-- Assumes all params mandatory and not empty
-- May override this behavior in subclasses
if isEmptyString(parsed_param) then
-- Reset any possibly set param
self.parsed_params = nil
return false
end
self.parsed_params[param] = parsed_param
end
-- Ok, parsin has been successful
return true
end
-- ##############################################
-- @brief Parses params submitted along with the REST endpoint request. If parsing fails, a REST error is sent.
-- @param params_table A table with submitted params, either _POST or _GET
-- @return True if parameters parsing is successful, false otherwise
function datasource:_rest_read_params(params_table)
if not self:read_params(params_table) then
rest_utils.answer(rest_utils.consts.err.widgets_missing_datasource_params)
return false
end
return true
end
-- ##############################################
-- @brief Send datasource data via REST
function datasource:rest_send_response()
-- Make sure this is a direct REST request and not just a require() that needs this class
if not _SERVER -- Not executing a Lua script initiated from the web server (i.e., backend execution)
or not _SERVER["URI"] -- Cannot reliably determine if this is a REST request
or not _SERVER["URI"]:starts(datasource.BASE_REST_PREFIX) -- Web Lua script execution but not for this REST endpoint
then
-- Don't send any REST response
return
end
if not self:_rest_read_params(_POST) then
-- Params parsing has failed, error response already sent by the caller
return
end
self:fetch()
rest_utils.answer(
rest_utils.consts.success.ok,
self.datamodel_instance:get_data()
)
end
-- ##############################################
-- @brief Deserializes REST endpoint response into an internal datamodel
-- @param rest_response_data Response data as obtained from the REST call
function datasource:deserialize(rest_response_data)
if rest_response_data and rest_response_data.RESPONSE_CODE == 200 then
local data = json.decode(rest_response_data.CONTENT)
local when = os.time()
if data and data.rc == rest_utils.consts.success.ok.rc then
self.datamodel_instance = self.meta.datamodel:new(data.rsp.header)
for _, row in ipairs(data.rsp.rows) do
self.datamodel_instance:appendRow(when, data.rsp.header, row)
end
end
end
end
-- ##############################################
-- @brief Returns instance metadata, which depends on the current instance and parsed_params
function datasource:get_metadata()
local res = {}
-- Render a url with submitted parsed_params
if self.meta.url then
local url_func = template.compile(self.meta.url, nil, true)
local url_rendered = url_func({
params = self.parsed_params,
})
res["url"] = url_rendered
end
return res
end
-- ##############################################
-- @brief Transform data according to the specified transformation
-- @param data The data to be transformed
-- @param transformation The transformation to be applied
-- @return transformed data
function datasource:transform(transformation)
return self.datamodel_instance:transform(transformation)
end
-- ##############################################
return datasource
-- ##############################################
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