使用Lua编写Web端模板引擎的实例代码分享

转载  2016-06-24   作者:乌龟壳   我要评论
这里我们给出一个使用Lua编写Web端模板引擎的实例代码分享,力求简洁(核心代码约为70行),仅实现最基本的模板功能:
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="http://sugarapple.net/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" rel="nofollow" type="text/css" media="screen" /> <link rel="stylesheet" href="http://www.jb51.net/js/2012/poshytip/tip-yellowsimple/tip-yellowsimple.css" type="text/css" /> <link rel="stylesheet" type="text/css" href="http://www.jb51.net/js/2011/fancybox/jquery.fancybox-1.3.4.css" media="screen" /> <script type="text/javascript" src="http://www.jb51.net/js/2012/jquery-1.7.1.min.js"></script> <script type="text/javascript" src="http://www.jb51.net/js/2012/jquery.form.js"></script> <script type="text/javascript" src="http://www.jb51.net/js/2011/fancybox/jquery.fancybox-1.3.4.pack.js"></script> <script type="text/javascript" src="http://www.jb51.net/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="http://www.jb51.net/js/2012/less-1.3.0.min.js"></script> <script type="text/javascript" src="http://www.jb51.net/js/scrolltopcontrol.js"></script> <script type='text/javascript' src='/js/jquery/jquery.atwho.js?ver=2013112501'></script> <link rel="stylesheet" type="text/css" href="http://www.jb51.net/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" rel="nofollow" /> <link rel="EditURI" type="application/rsd+xml" title="RSD" href="http://my.oschina.net/action/xmlrpc/rsd?space=1397642" rel="nofollow" /> <link rel="wlwmanifest" type="application/wlwmanifest+xml" href="http://my.oschina.net/action/xmlrpc/wlwmanifest?space=1397642" rel="nofollow" /> {# 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。

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