用C为LUA写一个超迷你的模板引擎.
时间：2019-07-08 10:04:01
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[导读]中午在做HTTP服务器，内嵌了LUA引擎作为业务逻辑部分. 但考虑到LUA输出HTML的性能不高，况且 MVC 模式开发网页已经习惯了，何不用C给lua写个最简单的模板引擎呢？说做就做, 项目时间很紧
中午在做HTTP服务器，内嵌了LUA引擎作为业务逻辑部分. 但考虑到LUA输出HTML的性能不高，况且 MVC 模式开发网页已经习惯了，何不用C给lua写个最简单的模板引擎呢？说做就做, 项目时间很紧张，所以必须确定目标，想了会儿。定了几个目标：
我要的是编译型的模板,要支持缓存。
不需要强大的模板逻辑方面的指令。将HTML模板文件编译成LUA源代码即可。LUA 还是比较容易扩展的，除了那栈用起来比较变态之外，经过了几个小时的奋斗，C+LUA代码。算是大功告成了。
#include#include#include#include#include#include#include#include "lib/automem.h"
#include "lua.h"
#include "lauxlib.h"
#include "lua-tpl.h"
/*
LUA 最简单的模板引擎.
*/
const char LUAFMT_TPL_META[]="LUAFMT_TPL";
void lua_cfmt_createmetatable (lua_State *L);
void lua_register_class(lua_State * L,const luaL_Reg * methods,const char * name,lua_CFunction has_index);
#if defined(_WIN32) || defined(_WIN64)
#define open _open
#define close _close
#define read _read
#define stat( x , y ) _stat( x , y )
#endif
static char * file_get_contents(const char * file,int * sz){
char * ret = NULL;
struct stat st;
int fd;
*sz = 0;
if ((fd = open(file, O_RDONLY|O_BINARY)) != -1)
{
if (fstat(fd, &st) != -1)
{
ret = (char *)malloc(st.st_size);
if(NULL != ret){
while( *sz < st.st_size){
*sz += read(fd, ret + *sz, st.st_size - (*sz));
_lseek(fd, *sz, SEEK_SET);
}
}
close(fd);
}
}
return ret;
}
int file_put_contents(const char* file_name, automem_t* mem)
{
FILE * fp = fopen(file_name,"wb+");
if(NULL != fp)
{
fwrite(mem->pdata, mem->size, 1, fp);
fclose(fp);
return 1;
}
return 0;
}
enum{
tpl_state_normal,
tpl_state_scode_1,
tpl_state_code,
tpl_state_ecode_1,
tpl_state_escape,
};
#define append_end_stringfield(a,b,c)
automem_append_voidp( (a) , cmd, lcmd);
automem_append_voidp( (a), (b) , (c));
automem_append_voidp( (a) , ecmd, lecmd);
automem_append_voidp( (a), ")n", 2);
static void lua_tpl_compile_local(lua_State * L, automem_t * mem, const char * buf,int lbuf){
int state = tpl_state_normal, i = 0;
const char * sbuf; char c;
size_t lcmd = sizeof("request.print([[") -1,
lecmd = sizeof("]])") -1,
lpre = 0;
const char * cmd = "request.print([[",
* ecmd = "]])",
*pre = NULL;
if(lua_isstring(L, 3))
cmd =luaL_checklstring(L, 3, &lcmd);
if(lua_isstring(L, 4))
ecmd =luaL_checklstring(L, 4, &lecmd);
if(lua_isstring(L, 5))
pre =luaL_checklstring(L, 5, &lpre);
if(NULL != pre){
automem_append_voidp(mem, pre, lpre);
automem_append_byte(mem,'n');
}
sbuf = buf;
while(i < lbuf){
c = buf[i];
switch (state)
{
case tpl_state_normal:
switch(c){
case '{':
state = tpl_state_scode_1;
break;
}
break;
case tpl_state_scode_1:
switch(c){
case '#':
state =tpl_state_code;
append_end_stringfield(mem,sbuf, &buf[i] - sbuf-1);
sbuf = &buf[i+1];
break;
default:
state = tpl_state_normal;
break;
}
break;
case tpl_state_code:
switch(c){
case '#':
state = tpl_state_ecode_1;
break;
}
case tpl_state_ecode_1:
switch(c){
case '}':
automem_append_voidp(mem,sbuf, &buf[i] - sbuf-1);
automem_append_byte(mem,'n');
sbuf = &buf[i+1];
state = tpl_state_normal;
break;
default:
state=tpl_state_code;
}
default:
break;
}
i++;
}
if(tpl_state_normal == state){
append_end_stringfield(mem,sbuf, &buf[i] - sbuf);
}
}
/* 对模板文件进行编译.*/
static int lua_tpl_compile(lua_State * L)
{
int cache = 0,i = 0, lbuf = 0;
size_t lfile;
const char *cfile = NULL, * file= luaL_checklstring(L, 1,&lfile),* buf;
automem_t mem;
if(lua_isboolean(L, 2))
cache =lua_toboolean(L, 2);
if(0 != cache){
struct stat st1,st2;
cfile=(char *)malloc(lfile+5);
memcpy((char *)cfile,file,lfile);
strcpy((char *)cfile+lfile,".tpl");
if((0 == stat(file,&st1)) && (0 == stat(cfile, &st2)))
{
if(st1.st_mtime <= st2.st_mtime)
{
if(NULL != (buf = file_get_contents(cfile, &lbuf)))
{
free((void *)cfile);
lua_pushlstring(L,buf, lbuf);
goto lua_tpl_compile_final;
}
}
}
}
if(NULL != (buf = file_get_contents(file, &lbuf)))
{
automem_init(&mem,lbuf + 1024);
lua_tpl_compile_local(L, &mem, buf, lbuf);
free((void*)buf);
lua_pushlstring(L,(char *)mem.pdata,mem.size);
if(0 != cache && NULL !=cfile)
file_put_contents(cfile,&mem);
automem_uninit(&mem);
}
if(NULL != cfile)
free((void *)cfile);
lua_tpl_compile_final:
return 1;
}
static luaL_Reg fmt_tpl_reg[] = {
{"compile",lua_tpl_compile},
{NULL,NULL}
};
int luaopen_cfmt_tpl(lua_State * L)
{
luaL_newlib(L, fmt_tpl_reg);
lua_cfmt_createmetatable(L);
return 1;
}整个LUA模块扩展就1个函数 compile()。在LUA中的原型如下：
string compile(filePath,cached, write, prefix,suffix,init)
功能: 将html模板编译为lua代码.
参数:
filePath: html源文件的路径.cached: 是否需要缓存.writer: 内容输出函数名.prefix: 文件分界符前缀.init:初始代码,用于做参数展开之类的工作.
当然,光有C的接口还不够，为了使它变得简单易用，还需要用LUA对其包装一下^_^, 包装代码如下:
function util.tpl(writer)
local t = require "cfmt.tpl"
local tpl = {}
local args = {}
local _prefix='[=['
local _suffix=']=]'
-- 创建的时候指定 writer
if nil ~= writer then args['_']=writer end
function tpl:assign(name,value)
args[name]=value
end
function tpl:boundary(prefix, suffix) --修改字符串边界符
if nil ~= prefix then _prefix=prefix end
if nil ~= suffix then _suffix=suffix end
end
function tpl:display(tpl,cache,writer) -- tpl 模板文件位置, cache 是否需要缓存 writer 可选,如果创建对象的时候指定了的话.
local i=1
if nil~=writer then args['_']=writer end
local init = {'local args = ...'}
for key,val in pairs(args) do
init[#init+1]='local '..key..'=args["'..key..'"]'
i=i+1
end
init = table.concat(init,'n')
local code =t.compile(tpl,cache,'_('.._prefix, _suffix,init)
load(code)(args)
end
return tpl;
end接下来用起来就简单多了,上测试代码.
---外部进来的数据在这里做检测
function login:request(r)
local tpl = (require "util").tpl(r.print)
local users ={
{['ID']=1,['username']='bywayboy',['age']=31},
{['ID']=1,['username']='liigo',['age']=31},
{['ID']=1,['username']='sunwei',['age']=8},
}
local b={['a']=12}
tpl:assign('users',users);
tpl:assign('title',"测试模板变量.")
tpl:assign('name',"某某童鞋")
tpl:display("D:\VC\CmdChannel\win32\Debug\test.html",true)
end
再来一个模板文件示例:
{#_(title)#}--方121212法ID姓名年龄{# for key,val in pairs(users) do#}{#_(val['ID']) #}{#_(val['username'])#}{#_(val['age'])#}{#end#}{#_(name)#}
该文件最终生成的缓存文件为:
local args = ... local _=args["_"] local name=args["name"] local users=args["users"] local title=args["title"] _([=[]=]) _(title) _([=[--方121212法ID姓名年龄]=]) for key,val in pairs(users) do _([=[]=]) _(val['ID']) _([=[]=]) _(val['username']) _([=[]=]) _(val['age']) _([=[]=]) end _([=[]=]) _(name) _([=[]=])
输出结果如图:
最终生成的HTML代码如下:
测试模板变量.--方121212法ID姓名年龄1bywayboy311liigo311sunwei8某某童鞋
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