Re: Embedding - user inputted scripts design advice
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- Subject: Re: Embedding - user inputted scripts design advice
- From: Sean Conner <sean@...>
- Date: 2012年5月14日 19:42:06 -0400
It was thus said that the Great Bruce Wheaton once stated:
> What's the usual way to deal with the user changing their scripts in an
> app with embedded lua scripting? I presume I really have to reset the lua
> state in some way, so any functions that were defined (or variables) that
> they no longer want are removed correctly?
>
> Is there an accepted way to retain values of the items that they did
> leave, to help with the case of a simple change, like to a calculation?
>
> And then is it usual to reset and rebind all external class/object
> bindings, or is a 'soft' reset possible?
It really depends upon the use case. You can reset the Lua state (or
rather, close it, then re-open and re-initialize a new one), or re-use the
existing Lua state.
For syslogintr [1] I don't bother with resetting the Lua state at all if
the given script is reloaded. I do, however, do this (from [2]):
if blocked == nil then
blocked = {}
setmetatable(blocked,{ __index = function(t,k) return 0 end })
os.execute("iptables --table filter -F INPUT")
end
to keep from resetting some persistent data [3]. But in general, there are
no hard and fast rules.
-spc
[1] http://www.conman.org/software/syslogintr/
https://github.com/spc476/syslogintr
[2] https://github.com/spc476/syslogintr/blob/master/modules/ssh-iptables.lua
[3] This module of syslogintr tracks failed ssh attempts, and after five
attempts, will block the offending IP address. The blocks are
removed after a few hours to keep the ruleset in iptables from
ever-increasing.