使用Lua编写Web端模板引擎的实例代码分享
ltemplate.lua
localinsert=table.insert localremove=table.remove localconcat=table.concat localformat=string.format localloaded={} localpartten="(.-){#([^#].-[^#])#}()" localcontent={} localcur_content=nil localfunctionob_start() cur_content={} insert(content,cur_content) end localfunctionob_get_clean() localret=concat(cur_content) remove(content) cur_content=content[#content] returnret end localfunctionecho(value) insert(cur_content,value) end localfunctioninclude(path,params) localbitcode=loaded[path] ifnotbitcodethen localfp=io.open(path,"rb") localtemplate=fp:read('*a') fp:close() localresults={} locallast_endpos=0 foroutside,inside,endposintemplate: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 localenv={ include=include, echo=echo, ob_start=ob_start, ob_get_clean=ob_get_clean } setmetatable(env,{__index=function(tb,k) returnparams[k]or_G[k] end}) setfenv(bitcode,env) bitcode() end fori=1,100000do ob_start() include(arg[1],{ params={ a='1234', b='4321' } }) ob_get_clean() end
master.html
<!DOCTYPEhtmlPUBLIC"-//W3C//DTDXHTML1.0Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <htmllang='zh-CN'xml:lang='zh-CN'xmlns='http://www.w3.org/1999/xhtml'> <head> <metahttp-equiv="Content-Type"content="text/html;charset=UTF-8"/> <metahttp-equiv="Content-Language"content="zh-CN"/> <metaname="robots"content="index,follow"/> <linkrel="shortcuticon"type="image/x-icon"href="/img/favicon.ico"/> <title>child'spersonalpage-开源中国社区</title> <linkrel="stylesheet/less"href="http://my.oschina.net/lostchild/styles.less?ver=20131219&date=20131110185237"type="text/css"media="screen"/> <linkrel="stylesheet"href="/js/2012/poshytip/tip-yellowsimple/tip-yellowsimple.css"type="text/css"/> <linkrel="stylesheet"type="text/css"href="/js/2011/fancybox/jquery.fancybox-1.3.4.css"media="screen"/> <scripttype="text/javascript"src="/js/2012/jquery-1.7.1.min.js"></script> <scripttype="text/javascript"src="/js/2012/jquery.form.js"></script> <scripttype="text/javascript"src="/js/2011/fancybox/jquery.fancybox-1.3.4.pack.js"></script> <scripttype="text/javascript"src="/js/2012/poshytip/jquery.poshytip.min.js"></script> <scripttype="text/javascript"src="/js/2011/oschina.js?ver=20121007"></script> <scripttype="text/javascript"src="/js/2012/less-1.3.0.min.js"></script> <scripttype="text/javascript"src="/js/scrolltopcontrol.js"></script> <scripttype='text/javascript'src='/js/jquery/jquery.atwho.js?ver=2013112501'></script> <linkrel="stylesheet"type="text/css"href="/js/jquery/jquery.atwho.css"/> <linkrel="alternate"type="application/rss+xml"title="lostchild最新博客"href="http://my.oschina.net/lostchild/rss"/> <linkrel="EditURI"type="application/rsd+xml"title="RSD"href="http://my.oschina.net/action/xmlrpc/rsd?space=1397642"/> <linkrel="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("helloWorld") </script> {#localheader=ob_get_clean()#} {#ob_start()#} <table> {#fork,vinpairs(params)do#} <tr> <td>{#echo(k)#}</td> <td>{#echo(v)#}</td> </tr> {#end#} </table> {#localcontent=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~]#timelualtemplate.luatemp.htmlreal0m1.867s
user0m1.862s sys0m0.004s
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。