使用Lua编写Web端模板引擎的实例代码分享-Lua

ltemplate.lua

				?

									local insert = table.insert

									local remove = table.remove

									local concat = table.concat

									local format = string.format

									local loaded = {}

									local partten = "(.-){#([^#].-[^#])#}()"

									local content = {}

									local cur_content = nil

									local function ob_start()

									 cur_content = {}

									 insert(content, cur_content)

									end

									local function ob_get_clean()

									 local ret = concat(cur_content)

									 remove(content)

									 cur_content = content[#content]

									 return ret

									end

									local function echo(value)

									 insert(cur_content, value)

									end

									local 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()

									end

									for 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'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  0m1.867s

				?

									user  0m1.862s

									sys   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。

使用Lua编写Web端模板引擎的实例代码分享

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