rework hosts map with widget (#5080)

scripts/lua/modules/widget_gui_utils.lua

@@ -0,0 +1,137 @@
+--
+-- (C) 2013-21 - ntop.org
+--
+local dirs = ntop.getDirs()
+package.path = dirs.installdir .. "/scripts/lua/modules/pools/?.lua;" .. package.path
+
+require("lua_trace")
+require("lua_utils")
+
+local json = require("dkjson")
+local template_utils = require("template_utils")
+
+local widget_gui_utils = {}
+
+-- a table with registered widgets to render
+local registered_widgets = {
+    charts = {
+        -- [widgetName] = registeredWidget
+    }
+}
+
+local function build_query_params(params)
+
+    local query = "?"
+    local t = {}
+ 
+    for key, value in pairs(params) do
+        t[#t+1] = string.format("%s=%s", key, value)
+    end
+    
+    return query .. table.concat(t, '&')
+end
+
+local function build_css_styles(css_styles)
+
+    local style = {}
+    
+    for name, value in pairs(css_styles) do 
+        style[#style+1] = string.format("%s:%s", name, value)
+    end
+
+    return table.concat(style, ";")
+
+end
+
+function widget_gui_utils.register_chart_widget(name, type, update_time, datasources, additional_params)
+
+    -- check if exists a widget with the same name
+    if table.has_key(registered_widgets, name) then
+        traceError(TRACE_WARNING, TRACE_CONSOLE, string.format("Overriding existing [%s] widget...", name))
+    end
+
+    registered_widgets.charts[name] = {
+        type = type,
+        update_time = update_time,
+        datasources = datasources,
+        params = additional_params
+    }
+
+end
+
+--- Shortcut Functions
+
+function widget_gui_utils.register_bubble_chart(name, update_time, datasources, additional_params)
+    widget_gui_utils.register_chart_widget(name, 'bubble', update_time, datasources, additional_params)
+end
+
+function widget_gui_utils.register_pie_chart(name, update_time, datasources, additional_params)
+    widget_gui_utils.register_chart_widget(name, 'pie', update_time, datasources, additional_params)
+end
+
+function widget_gui_utils.register_doughnut_chart(name, update_time, datasources, additional_params)
+    widget_gui_utils.register_chart_widget(name, 'doughnut', update_time, datasources, additional_params)
+end
+
+---Render all registered chart widgets.
+---@return string
+function widget_gui_utils.render_chart_widgets()
+
+    local template_buff = {}
+
+    for widget_name, widget in pairs(registered_widgets.charts) do
+
+        local rendered_html = template_utils.gen("widgets/chart-widget.template", {
+            widget_name = widget_name, widget = widget, json = json
+        })
+
+        template_buff[#template_buff + 1] = rendered_html
+    end
+
+    return table.concat(template_buff, "\n")
+end
+
+---Get an array of chart widgets registered
+---@return table
+function widget_gui_utils.get_registered_chart_names()
+
+    local names = {}
+    
+    for name, _ in pairs(registered_widgets.charts) do
+        names[#names+1] = name
+    end
+
+    return names
+end
+
+---Render a chart widget into a string
+---@param widget_name string The widget's name to render
+---@param additional_params table Additional paramaters used to customize the widgets {css_styles = {...}, displaying_label = '...'}
+---@return string The chart widget template rendered
+function widget_gui_utils.render_chart(widget_name, additional_params)
+
+    local displaying_label = additional_params.displaying_label or widget_name
+    local css_styles = additional_params.css_styles or {}
+
+    if not (table.has_key(registered_widgets.charts, widget_name)) then
+        return ""
+    end
+
+    local widget = registered_widgets.charts[widget_name]
+
+    local rendered_html = template_utils.gen("widgets/chart-widget.template", {
+        json = json, 
+        widget_name = widget_name, 
+        widget = widget, 
+        css_styles = build_css_styles(css_styles),
+        displaying_label = displaying_label
+    })
+
+    return rendered_html
+end
+
+function widget_gui_utils.datasource(name, params)
+    return { endpoint = name .. build_query_params(params) }
+end
+
+return widget_gui_utils