1200px-Lua_logo.svg.png
一、定义变量
- 数字，双精度
local free_space = 6
free_space = 6.666666
- 字符串度
local usb_local_path = "/mnt/sda1/"
local plug_flash_db = '/usr/share/ipk/plug_db'
--定义多行字符串
local plug_config_path = [[/tmp/init_plug.config]]
- 空类型
local plug_location = nil
注：nil，即NULL，支持垃圾回收
- 布尔类型
-------------------------------
--fasle: nil & false
--true: 0 & "" & 非空字符串
-------------------------------
local IS_USB_EXIST = false
- 表
--空表
local plug_log = {}
--数组
local arr = {
[1] = 10,
[2] = 20,
[3] = 30,
[4] = 40,
[5] = 50
}
--键值对
local plug_get_opt_list = {
["get_plug"] = "get_plug",
["get_plug_status"] = "get_plug_status"
}
local PLUG_STATUS = {
["DOWNLOADING"] = 1,
["INSTALLING"] = 2,
["FAILED"] = 3,
["START"] = 4,
["STOP"] = 5
}
二、控制语句
- if-else 语句
if plug_opt == "remove" then
res = remove_plugin(plug_code, plug_exec_fname)
elseif plug_opt == "cmd_ctrl" then
res = control_plugin(cmd_argc_list, plug_exec_fname)
else
res, code = false, PLUG_OPT_CODE.ERROR
end
- while 循环
while value >= 36 do
local temp = value % 36
...
end
- for循环
local flash_db_res, res = {}, {}
flash_db_res = db_util:fetch_plug_status(plug_code)
for k, v in pairs(flash_db_res) do
table.insert(res, v)
end
for i = 1, #week_repeat, 2 do
...
end
- until循环
repeat
...
until sum > 1000
三、函数
- 函数与其他类型一样，属于基本类型，且也分局部和全局之分
- 普通函数
function do_remove_by_opkg(plug_name)
local cmd = "opkg remove "..plug_name
plug_mkdir_slink()
lue(cmd)
plug_rmdir_slink()
end
- 多返回值函数
function install_plug(plug_code, plug_md5, plug_url)
...
--TODO:subthread
local plug_local_path = download_plug(plug_code, plug_url)
local check_md5_flag = check_plug_md5(plug_md5)
if check_md5_flag == false then
clr_failed_plug_from_db(plug_code)
return false, PLUG_OPT_CODE.CHECK_MD5_ERROR
end
...
return true, PLUG_OPT_CODE.NORMAL
end
- 递归函数
function RecursionPreOrder(BiTree t){
if(t ~= nil){
print(t.data);
RecursionPreOrder(t.lchild);
RecursionPreOrder(t.rchild);
}
}
- 闭包函数
function external_func()
local i = 0
function internal_func()
i = i + 1
return i
end
return internal_func
end
local closure_func = external_func()
print(closure_func()) --1
print(closure_func()) --2
print(closure_func()) --3
print(closure_func()) --4
四、Table操作
- 初始化table
local PLUG_OPT_CODE = {
["NORMAL"] = 200,
...
}
- 获取table值
print(PLUG_OPT_CODE.NORMAL)
print(PLUG_OPT_CODE["NORMAL"])
- 遍历table
local is_uniq = true
for usb_k,usb_v in pairs(usb_db_res) do
for res_k, res_v in pairs(res) do
if res_v["plug_code"] == usb_v["plug_code"] then
is_uniq = false
break
end
end
if is_uniq == true then
table.insert(res, usb_v)
end
end
五、面向对象EXAMPLE
- db_util类
module("plug_db_util", package.seeall)
db_util = {}
function db_util:fetch_plug(plug_code)
...
end
- db_util类实例
local db_util = require "plug_db_util".db_util
function get_plug_from_db(plug_param)
...
if plug_param.plug_code ~= nil and plug_param.plug_opt ~= "get_plug_status" then
init_plug_install_local_path(STORAGE_NODE["FLASH"])
plug_location = STORAGE_NODE["FLASH"]
local res = db_util:fetch_plug(plug_param.plug_code)
if next(res) == nil and IS_USB_EXIST == true then
init_plug_install_local_path(STORAGE_NODE["USB"])
plug_location = STORAGE_NODE["USB"]
res = db_util:fetch_plug(plug_param.plug_code)
end
...
end
...
end
六、常用标准库函数
- string库
local str = [[rh_Jameson]]
print( string.lower(str) ) --rh_jameson
print( string.upper(str) ) --RH_JAMESON
print( string.len(str) ) --10
--字符串重复输出
print( string.rep(str, 3) ) --rh_Jamesonrh_Jamesonrh_Jameson
--字符串截取
print( string.sub(str, 4, -1) ) --Jameson
print( string.sub(str, 4, 10) ) --Jameson
print( string.sub(str, 4, #str) ) --Jameson
--字符串查找，返回起始 & 结束索引
print( string.find(str, "%_")) --3 3
print( string.sub(str, string.find(str, "%_") + 1, #str ) ) --Jameson
--字符串匹配，匹配不上返回nil
print( string.match(str, "%_") ) --_
--字符串替换
print( string.gsub(str, '_', '@')) --rh@Jameson 1
--字符串格式化输出
--openwrt is operate system of router, 6666 ...
print( string.format("%s is %s of router, %d %s", "openwrt", "operate system", 6666, "..."))
- os库
os.remove("/tmp/"..lock_file)
os.rename("/tmp/"..lock_file.."rename")
os.execute("rm /tmp/init_plug.config")
os.time()
os.date()
- io库
---------------------
--PLUG OPT LOCK DEMO
----------------------
function plug_opt_lock(lock_file)
local ct = os.time()
local file = io.open("/tmp/".. lock_file, "w")
file:write(ct);
file:close();
end
function is_plug_lock(lock_file, timeval)
local file = io.open("/tmp/"..lock_file, "r")
if file == nil then
return false
end
local ctn = file:read()
if ctn == nil or ctn == "" then
ctn = 0
end
file:close();
local ct = os.time()
if(ct - tonumber(ctn) > timeval) then
os.remove("/tmp/"..lock_file);
return false;
end
return true;
end
---------------------
--CRON WIFI DEMO
----------------------
function get_smart_wifi_info()
local res = {}
local smart_wifi_info = io.open("/etc/crontabs/root", "r")
if smart_wifi_info == nil then
return "false"
end
for line in smart_wifi_info:lines() do
...
end
...
smart_wifi_info:close()
return res;
end
- table库
for key,val in pairs(key_res) do
table.insert(format_res, key)
end
table.sort(format_res)
function randomstring(len)
local allstr = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
local maxlen = string.len(allstr)
local srt = {}
for i=1,len,1 do
local index = random(1, maxlen)
srt[i] = string.sub(allstr, index, index)
end
return table.concat(srt, "")
end
local tb_ex = {}
local tb_inter = {
["name"] ="rh_Jameson",
["en-name"] ="rh_Jameson",
["zh-name"] ="rh_Jameson"
}
for k, v in pairs(tb_inter) do
print(k .. " : " .. v)
end
table.insert(tb_ex, tb_inter)
table.insert(tb_ex, {
["mac"] = 1,
["ip"] = 2,
["wifi"] = 3,
["devicename"] = 4,
["orgname"] = 5
})
for k, v in pairs(tb_ex) do
--print(k .. " : " .. v)
print("----------------------")
print(k)
print(v)
for kk, vv in pairs(v) do
print(kk)
print(vv)
end
print("----------------------")
end
七、其他函数
- type(): 返回参数的类型名
if type(plug_code_list) == "string" then
plug_code_list = cjson.decode(plug_code_list)
end
- next(): 可用来检测表是否为空
if next(ret) ~= nil then
table.insert(res, ret)
end
- pcall(): 类似try {...} catch {...}
function plug_opt(plug_param)
local format_res, exec_res = {}, {}
local status = nil
status, exec_res = pcall(plug_opt_exec, plug_param)
if status == false then
log_res(plug_param.plug_opt, exec_res)
return print_res(format_res, exec_res, PLUG_OPT_CODE.OTHER_ERROR)
else
format_res = exec_res
return format_res
end
end
- math.random()
function random(m, n)
local socket = require("socket")
local t = string.format("%f", socket.gettime())
local st = string.sub(t, string.find(t, "%.") + 1, -1)
math.randomseed(tonumber(string.reverse(st)))
return math.random(m,n)
end
八、设计模式： lua将多个if-else优化成键值对形式
原有形式：
function do_plug_set_opt(res, plug_opt, plug_code, plug, plug_param)
local format_res = res
local code = nil
if plug_code and plug_opt == "install" then
local install_node = check_plug_code_flag(plug_code)
local plug_install_location, specify_res = specify_install_storage_node(install_node, res)
if specify_res["code"] then
require "MZLog".log(3, res)
log_res(plug_param.plug_opt, res)
return specify_res
end
res, code = install_plugin(plug_code, plug_param.plug_md5, plug_param.plug_url, plug_install_location)
elseif plug_code and plug["plug_name"] then
local plug_exec_fname = get_plug_exec_file_name(plug["plug_code"])
init_plug_install_local_path(plug_location)
if plug_opt == "remove" then
res = remove_plugin(plug_code, plug_exec_fname)
elseif plug_opt == "start"then
res = start_plugin(plug_code, plug_exec_fname)
elseif plug_opt == "stop" then
res = stop_plugin(plug_code, plug_exec_fname)
elseif plug_opt == "cmd_ctrl" then
res = control_plugin(plug_param.cmd_argc_list, plug_exec_fname)
elseif plug_opt == "upgrade" then
res, code = upgrade_plugin(plug_code, plug_param.plug_md5, plug_param.plug_url)
end
end
if code == nil then
format_res = print_res(format_res, res, PLUG_OPT_CODE.NORMAL)
else
format_res = print_res(format_res, res, code)
end
return format_res
end
优化形式：
plug_set_opt_action = {
["install"] = plug_opt_util.install_plugin,
["async_install"] = plug_opt_util.async_install_plugin,
["remove"] = plug_opt_util.remove_plugin,
["async_remove"] = plug_opt_util.async_remove_plugin,
["start"] = plug_opt_util.start_plugin,
["stop"] = plug_opt_util.stop_plugin,
["cmd_ctrl"] = plug_opt_util.control_plugin,
["upgrade"] = plug_opt_util.upgrade_plugin,
["async_upgrade"] = plug_opt_util.async_upgrade_plugin
}
--------------------------------plug_opt_util-----------------------------------
function do_plug_set_opt(res, plug_opt, plug_code, plug, plug_param)
local format_res, code = res, nil
if plug["plug_name"] then
plug_param.plug_exec_fname = plug_info_util.get_plug_exec_file_name(plug["plug_code"])
local plug_location = plug_info_util.get_plug_location()
init_plug_install_local_path(plug_location)
end
code, res = plug_set_opt_action[plug_opt](plug_param)
format_res = print_res(format_res, res, code)
return format_res
end
