Initial work for widget implementation

scripts/lua/modules/widget_utils.lua

@@ -0,0 +1,163 @@
+--
+-- (C) 2020 - ntop.org
+--
+local widgets_utils = {}
+
+require ("lua_utils")
+local json = require("dkjson")
+local datasource_utils = require("datasource_utils")
+
+local REDIS_BASE_KEY = "ntopng.widgets"
+local DEFAULT_WIDGET_SRC = ntop.getHttpPrefix() .. "/lua/datasource/main.lua"
+
+local WIDGET_TYPES = {
+    pie = {
+        i18n = 'Pie'
+    },
+    doughnut = {
+        i18n = "Doughnut"
+    },
+    polar = {
+        i18n = "Polar"
+    },
+    table = {
+        i18n = "Table"
+    },
+    line = {
+        i18n = "Line"
+    }
+}
+
+local function create_hash_widget(name, ds_hash)
+    return ntop.md5(name .. ds_hash)
+end
+
+local function check_widget_params(name, ds_hash, widget_type, params)
+
+    if (isEmptyString(name)) then
+        return false, "The widget name cannot be empty!"
+    end
+
+    if (isEmptyString(ds_hash)) then
+        return false, "The associated datasource hash cannot be empty!"
+    end
+    -- Check if the passed ds hash is valid
+    if (not datasource_utils.is_hash_valid(ds_hash)) then
+        return false, "The passed hash is not valid!"
+    end
+
+    if (isEmptyString(widget_type) or WIDGET_TYPES[widget_type] == nil) then
+        return false, "The passed widget type is not valid!"
+    end
+
+    if (params == nil) then
+        return false, "The params are not valid!"
+    end
+
+    return true, nil
+end
+
+function widgets_utils.get_widget_types()
+    return WIDGET_TYPES
+end
+
+-------------------------------------------------------------------------------
+-- Create a new widget and save it to redis.
+
+-- @return The function returns `true` if the passed
+--         arguments meet the precondition, otherwise `false`
+-------------------------------------------------------------------------------
+function widgets_utils.add_widget(name, ds_hash, widget_type, params)
+
+    local args_are_valid, message = check_widget_params(name, ds_hash, widget_type, params)
+    if (not args_are_valid) then
+        return args_are_valid, message
+    end
+
+    local key_widget = create_hash_widget(name, ds_hash)
+
+    local new_widget = {
+        key = key_widget,
+        name = name,
+        ds_hash = ds_hash,
+        params = params,
+        type = widget_type,
+        src = DEFAULT_WIDGET_SRC
+    }
+
+    ntop.setHashCache(REDIS_BASE_KEY, key_widget, json.encode(new_widget))
+
+    return true, key_widget
+end
+
+-------------------------------------------------------------------------------
+-- Edit the data source
+-- @return True if the edit was successful, false otherwise
+-------------------------------------------------------------------------------
+function widgets_utils.edit_widget(widget_key, name, ds_hash, widget_type, params)
+
+    local args_are_valid, message = check_widget_params(name, ds_hash, widget_type, params)
+    if (not args_are_valid) then
+        return args_are_valid, message
+    end
+
+    local json_widget = ntop.getHashCache(REDIS_BASE_KEY, widget_key)
+
+    if (isEmptyString(json_widget)) then
+        return false, "The widget was not found!"
+    end
+
+    local widget = json.decode(json_widget)
+    widget.name = name
+    widget.ds_hash = ds_hash
+    widget.type = widget_type
+    widget.params = params
+
+    ntop.delHashCache(REDIS_BASE_KEY, widget_key)
+    ntop.setHashCache(REDIS_BASE_KEY, widget_key, json.encode(widget))
+
+    return true, widget_key
+end
+
+-------------------------------------------------------------------------------
+-- Delete the widget from redis
+-- @param widget_key The key of the widget to be removed (not nil)
+-- @return True if the delete was successful, false otherwise
+-------------------------------------------------------------------------------
+function widgets_utils.delete_widget(widget_key)
+
+    if (isEmptyString(widget_key)) then
+        return false, "The widget key cannot be empty!"
+    end
+
+    if (isEmptyString(ntop.getHashCache(REDIS_BASE_KEY, widget_key))) then
+        return false, "The widget to be removed was not found!"
+    end
+
+    ntop.delHashCache(REDIS_BASE_KEY, widget_key)
+
+    return true, widget_key
+end
+
+-------------------------------------------------------------------------------
+-- Get all widgets stored in redis
+-- @return An array of widgets stored in redis, if no any widgets was found
+-- it returns an empty array
+-------------------------------------------------------------------------------
+function widgets_utils.get_all_widgets()
+
+    local widgets = ntop.getHashAllCache(REDIS_BASE_KEY)
+    if (widgets == nil) then
+        return {}
+    end
+
+    local all_widgets = {}
+
+    for _, json_source in pairs(widgets) do
+        all_widgets[#all_widgets + 1] = json.decode(json_source)
+    end
+
+    return all_widgets
+end
+
+return widgets_utils