openwrt: add a Flukso RESTful API to the lucid dispatcher

mote/v1/openwrt/package/luci/modules/admin-mini/luasrc/controller/restful.lua

@@ -0,0 +1,79 @@
+--[[
+LuCI - Lua Configuration Interface
+
+Copyright 2008 Steven Barth <steven@midlink.org>
+Copyright 2008 Jo-Philipp Wich <xm@leipzig.freifunk.net>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+$Id: rpc.lua 5118 2009-07-23 03:32:30Z jow $
+]]--
+
+module ("luci.controller.restful", package.seeall)
+
+function index()
+	local uci = require "luci.model.uci".cursor()
+
+	if uci:get("flukso", "main", "localEnable") == "1" then
+		uci:foreach("flukso", "sensor", function(section)
+			entry({section.id}, call("rest_sensor", {section.id}))
+		end)
+	end
+end
+
+--- Decode a URL query string
+-- @param QS		the to-be-decoded query string
+-- @return		table containing [name] = value pairs
+-- @see			rest_sensor
+local function decode(QS)
+	local param = {}
+
+	for name, value in QS:gmatch("([^&=]+)=([^&=]+)") do
+		param[name] = value
+	end
+
+	return param
+end
+
+--- Return a 400 error code to the client
+-- @param message	custom error message (optional)
+-- @return		false
+function error400(message)
+	local http     = require "luci.http"
+
+	http.status(400, "Bad Request")
+	message = message or "Bad Request"
+
+	http.prepare_content("text/plain")
+	http.write(message)
+	
+	return false
+end
+
+--- Callback function for Flukso RESTful API
+-- @param id		requested sensor id (table)
+-- @return		json-encoded time series data 
+function rest_sensor(id)
+	local http     = require "luci.http"                                                          
+	local ltn12    = require "luci.ltn12"                                                         
+	local uci      = require "luci.model.uci".cursor()
+
+	local path     = uci:get("flukso", "main", "local")
+	local param    = decode(http.getenv("QUERY_STRING"))
+
+	if param.interval == "minute" and param.unit == "watt" then
+		http.prepare_content("application/json")
+		http.write("sensor:" .. (id[1] or 'nok') .. "\n" ..
+			   "query string:" .. http.getenv("QUERY_STRING") .. "\n" ..
+			   "contents:")
+
+		local source = ltn12.source.file(io.open(path .. "/" .. id[1], "r"))
+		ltn12.pump.all(source, http.write)
+	else
+		error400("Malformed query string: 'interval' and 'unit' query parameters are obligatory.")
+	end
+end