Lua Rings库介绍

Rings需求

　　如果有一段lua脚本代码，本来来源不可靠，可能有安全性问题，或者不像让这份代码污染了正在执行的lua环境，则需要lua rings工具出厂了。

其在主lua环境中，即在宿主脚本中，调用rings库创建一个子的lua环境，将不可靠的lua代码在子lua环境中运行，运行完毕环境销毁，一点都不影响宿主环境。

Rings is a library which provides a way to create new Lua states from within Lua. It also offers a simple way to communicate between the creator (master) and the created (slave) states.

资源

官网介绍，有帮助文档：

http://keplerproject.github.io/rings/manual.html

git hub可以下载最新源代码：

https://github.com/keplerproject/rings

接口

基本接口

rings.new (env) --- 创建一个lua环境
Returns a newly created Lua state. Takes an optional environment to be used by remotedostring. If the environment is nil, it defaults to the master_M or _G tables.
state:close () --- 销毁创建的lua环境
Closes the state.
state:dostring (string, ...) ---- 在lua环境中执行一段lua代码
Executes a string in the slave state. The arguments could be accessed exactly as in a vararg function. Valid types of arguments and return values are: number, string, boolean, nil and userdata (which are converted to lightuserdata).
Returns a boolean indicating the status of the operation, followed by the returned values or an error message in case of error.

此插件还考虑到，子环境如何存储数据，保证与宿主环境可以交换数据：

Stable

Stable is a simple API which provides a way for a slave state to store and retrieve data to and from its master state. This library is not opened automatically in a slave state.

stable.get (key)
Returns the value of a given key.
stable.set (key, value)
Stores a value associated to a key. Returns nothing.

实验

参考其源代码中最简单的例子sample.lua

- $Id: sample.lua,v 1.4 2008/05/30 18:44:05 carregal Exp $

require"rings"

S = rings.new ()

data = { 12, 13, 14, }
print (S:dostring ([[
aux = {}
for i, v in ipairs {...} do
        table.insert (aux, 1, v)
end
return unpack (aux)]], unpack (data)))

-- 主要在此处说明， 子环境不会污染宿主环境， 同时说明了 宿主环境中执行不可靠代码， 将会污染宿主环境自身
if nil == aux then
        print("aux do not exist in Global Environment!");

        f = loadstring([[
                aux = {1}
        ]])
        print(f())          --> do lua code

        print("after call global dostring, aux created, aux[0]=="..aux[1]);
end

S:close ()

print("OK!")
~

实验结果：

xx:~/share_windows/openSource/lua/rings-master/tests$ lua sample.lua
true 14 13 12
aux do not exist in Global Environment!

after call global dostring, aux created, aux[0]==1
OK!