使用Lua编写Web端模板引擎的实例代码分享

时间：2021-05-22

ltemplate.lua

local insert = table.insertlocal remove = table.removelocal concat = table.concatlocal format = string.formatlocal loaded = {}local partten = "(.-){#([^#].-[^#])#}()"local content = {}local cur_content = nillocal function ob_start() cur_content = {} insert(content, cur_content)endlocal function ob_get_clean() local ret = concat(cur_content) remove(content) cur_content = content[#content] return retendlocal function echo(value) insert(cur_content, value)endlocal function include(path, params) local bitcode = loaded[path] if not bitcode then local fp = io.open(path, "rb") local template = fp:read('*a') fp:close() local results = {} local last_endpos = 0 for outside, inside, endpos in template:gmatch(partten) do insert(results, format("echo(%q)", outside)) insert(results, inside) last_endpos = endpos end insert(results, format("echo(%q)", template:sub(last_endpos))) results = concat(results, "\n") bitcode = assert(loadstring(results)) loaded[path] = bitcode end local env = { include = include, echo = echo, ob_start = ob_start, ob_get_clean = ob_get_clean } setmetatable(env, {__index = function(tb, k) return params[k] or _G[k] end}) setfenv(bitcode, env) bitcode()endfor i = 1, 100000 do ob_start() include(arg[1], { params = { a = '1234', b = '4321' } }) ob_get_clean()end

master.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html lang='zh-CN' xml:lang='zh-CN' xmlns='http://www.w3.org/1999/xhtml'><head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> <meta http-equiv="Content-Language" content="zh-CN"/> <meta name="robots" content="index, follow" /> <link rel="shortcut icon" type="image/x-icon" href="/img/favicon.ico" /> <title> child&apos;s personal page - 开源中国社区</title> <link rel="stylesheet/less" href="http://my.oschina.net/lostchild/styles.less?ver=20131219&date=20131110185237" type="text/css" media="screen" /> <link rel="stylesheet" href="/js/2012/poshytip/tip-yellowsimple/tip-yellowsimple.css" type="text/css" /> <link rel="stylesheet" type="text/css" href="/js/2011/fancybox/jquery.fancybox-1.3.4.css" media="screen" /> <script type="text/javascript" src="/js/2012/jquery-1.7.1.min.js"></script> <script type="text/javascript" src="/js/2012/jquery.form.js"></script> <script type="text/javascript" src="/js/2011/fancybox/jquery.fancybox-1.3.4.pack.js"></script> <script type="text/javascript" src="/js/2012/poshytip/jquery.poshytip.min.js"></script> <script type="text/javascript" src="/js/2011/oschina.js?ver=20121007"></script> <script type="text/javascript" src="/js/2012/less-1.3.0.min.js"></script> <script type="text/javascript" src="/js/scrolltopcontrol.js"></script> <script type='text/javascript' src='/js/jquery/jquery.atwho.js?ver=2013112501'></script> <link rel="stylesheet" type="text/css" href="/js/jquery/jquery.atwho.css" /> <link rel="alternate" type="application/rss+xml" title="lostchild最新博客" href="http://my.oschina.net/lostchild/rss" /> <link rel="EditURI" type="application/rsd+xml" title="RSD" href="http://my.oschina.net/action/xmlrpc/rsd?space=1397642" /> <link rel="wlwmanifest" type="application/wlwmanifest+xml" href="http://my.oschina.net/action/xmlrpc/wlwmanifest?space=1397642" /> {# echo(header) #}</head><body>{# echo(content) #}<body></html>

temp.html，继承master.html

{# ob_start() #}<script> alert("hello World")</script>{# local header = ob_get_clean() #}{# ob_start() #}<table>{# for k, v in pairs(params) do #}<tr> <td>{# echo(k) #}</td> <td>{# echo(v) #}</td></tr>{# end #}</table>{# local content = ob_get_clean() #}{# include('master.html', {header = header, content = content}) #}

循环十万次测试渲染速度（阿里云最便宜一款vps）

[root@AY130801221248587d02Z ~]# time lua ltemplate.lua temp.htmlreal 0m1.867suser 0m1.862ssys 0m0.004s

总结

由此可见渲染的速度还是非常快的，可以将此原型用于嵌入式设备中的页面上（用大量js实现的嵌入式设备页面兼容性不好）。而且嵌入式设备的界面需要简单明确，所以也不用太丰富的模版功能。

原理很简单：

1.用lua版的正则把模版内{#与#}之间的内容挖出来，原样输出成lua代码，其它部分则生成使用echo打印到某个缓冲区的lua代码。

2.将这个生成出来的代码使用loadstring编译。

3.通过setfenv实现loadstring后的模拟环境配置（用以提供模版内使用的echo，ob_start等函数，以及传入的参数）

4.执行这个编译后的函数即可。

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