void
ngx_http_lua_inject_socket_tcp_api(ngx_log_t *log, lua_State *L)
{
    ngx_int_t         rc;

    //void lua_createtable (lua_State *L, int narr, int nrec);
    //建立一個新的table並將之放在棧頂.narr是該table陣列部分的長度,nrec是該table hash部分的長度.
    //當我們確切的知道要放多少元素到table的時候,使用這個函式,lua可以預分配一些記憶體,提升效能.
    //如果不確定要存放多少元素可以使用 lua_newtable 函式來建立table.
    lua_createtable(L, 0, 4 /* nrec */);    /* ngx.socket */


    lua_pushcfunction(L, ngx_http_lua_socket_tcp);//棧頂
    ////////////////////////////////
    //    
    //   2 -1    ngx_http_lua_socket_tcp
    //   1 -2    {}   
    //////////////////////////////////////
    lua_pushvalue(L, -1);
    ////////////////////////////////
    //    
    //   3 -1    ngx_http_lua_socket_tcp
    //   2 -2    ngx_http_lua_socket_tcp
    //   1 -3    {}   
    //////////////////////////////////////



    lua_setfield(L, -3, "tcp");
    ////////////////////////////////
    //    
    //   2 -1    ngx_http_lua_socket_tcp
    //   1 -2    {"tcp"=ngx_http_lua_socket_tcp}   
    //////////////////////////////////////



    lua_setfield(L, -2, "stream");
    ////////////////////////////////
    //    
    //   1 -1    {"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp}   
    //////////////////////////////////////


    {
        const char  buf[] = "local sock = ngx.socket.tcp()"
                            " local ok, err = sock:connect(...)"
                            " if ok then return sock else return nil, err end";
        //載入並編譯記憶體中的一段Lua程式碼，然後作為一個程式碼塊(稱為chunk)壓入棧中/
        rc = luaL_loadbuffer(L, buf, sizeof(buf) - 1, "=ngx.socket.connect");//
    }
    ////////////////////////////////
    //   2 -1    "local sock ...." 
    //   1 -2    {"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp}   
    //////////////////////////////////////
    if (rc != NGX_OK) {
        ngx_log_error(NGX_LOG_CRIT, log, 0,
                      "failed to load Lua code for ngx.socket.connect(): %i",
                      rc);

    } else {
        lua_setfield(L, -2, "connect");
        ////////////////////////////////
        //  
        //   1 -1    {"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}   
        //////////////////////////////////////
    }

    lua_setfield(L, -2, "socket");
    ////////////////////////////////
    //  
    //   1 -1    {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}}   
    //////////////////////////////////////
    /* {{{req socket object metatable */
    lua_pushlightuserdata(L, &ngx_http_lua_req_socket_metatable_key);
    lua_createtable(L, 0 /* narr */, 5 /* nrec */);
    ////////////////////////////////
    //   3  -1    {}
    //   2  -2    ngx_http_lua_req_socket_metatable_key
    //   1  -3    {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}}   
    //////////////////////////////////////

    lua_pushcfunction(L, ngx_http_lua_socket_tcp_receive);

    ////////////////////////////////
    //   4  -1    ngx_http_lua_socket_tcp_receive
    //   3  -2    {}
    //   2  -3    ngx_http_lua_req_socket_metatable_key
    //   1  -4    {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}}   
    //////////////////////////////////////

    lua_setfield(L, -2, "receive");
    ////////////////////////////////
    //   3  -1    {"receive"=ngx_http_lua_socket_tcp_receive}
    //   2  -2    ngx_http_lua_req_socket_metatable_key
    //   1  -3    {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}}   
    //////////////////////////////////////


    lua_pushcfunction(L, ngx_http_lua_socket_tcp_receiveuntil);
    lua_setfield(L, -2, "receiveuntil");
    ////////////////////////////////
    //   3  -1    {"receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil}
    //   2  -2    ngx_http_lua_req_socket_metatable_key
    //   1  -3    {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}}   
    //////////////////////////////////////

    lua_pushcfunction(L, ngx_http_lua_socket_tcp_settimeout);
    lua_setfield(L, -2, "settimeout"); /* ngx socket mt */
    ////////////////////////////////
    //   3  -1    {"receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout}
    //   2  -2    ngx_http_lua_req_socket_metatable_key
    //   1  -3    {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}}   
    //////////////////////////////////////

    lua_pushcfunction(L, ngx_http_lua_socket_tcp_settimeouts);
    lua_setfield(L, -2, "settimeouts"); /* ngx socket mt */

   ////////////////////////////////
    //   3  -1    {"receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //   2  -2    ngx_http_lua_req_socket_metatable_key
    //   1  -3    {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}}   
    //////////////////////////////////////


    lua_pushvalue(L, -1);
    ////////////////////////////////
    //   4  -1    {"receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //   3  -2    {"receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //   2  -3    ngx_http_lua_req_socket_metatable_key
    //   1  -4    {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}}   
    //////////////////////////////////////
    lua_setfield(L, -2, "__index");
   ////////////////////////////////
    //   3  -1    {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //   2  -2    ngx_http_lua_req_socket_metatable_key
    //   1  -3    {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ...."}}   
    //////////////////////////////////////


    //lua_rawset和lua_settable(lua_State* L, int index)類似，但是直接賦值
    //lua_settable就是把表在lua堆疊中的值彈出來，index 是table 在堆疊中的位置，
    //假如 table 在 -3, 則key 應該是 -2，value 是 -1
    //相當於 table[key] = value.

    //table[]
    //////////////////////////////////////////////
    //
    //
    //
    //  1   -1     {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ....", "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}}}
    //////////////////////////////////////////////
    lua_rawset(L, LUA_REGISTRYINDEX);//直接賦值  LUA_REGISTRYINDEX是Lua登錄檔的偽索引
    /* }}} */



    /* {{{raw req socket object metatable */
    lua_pushlightuserdata(L, &ngx_http_lua_raw_req_socket_metatable_key);
    lua_createtable(L, 0 /* narr */, 6 /* nrec */);
    //////////////////////////////////////////////////////////////////////
    //
    //
    //
    //             {}
    //             ngx_http_lua_raw_req_socket_metatable_key
    //  1   -1     {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ....", "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}}}
    //////////////////////////////////////////////////////////////////


    lua_pushcfunction(L, ngx_http_lua_socket_tcp_receive);
    lua_setfield(L, -2, "receive");

    //////////////////////////////////////////////////////////////////////
    //
    //
    //
    //             { "receive"=ngx_http_lua_socket_tcp_receive}
    //             ngx_http_lua_raw_req_socket_metatable_key
    //  1   -1     {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ....", "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}}}
    //////////////////////////////////////////////////////////////////



    lua_pushcfunction(L, ngx_http_lua_socket_tcp_receiveuntil);
    lua_setfield(L, -2, "receiveuntil");
    //////////////////////////////////////////////////////////////////////
    //
    //
    //
    //             { "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil}
    //             ngx_http_lua_raw_req_socket_metatable_key
    //  1   -1     {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ....", "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}}}
    //////////////////////////////////////////////////////////////////


    lua_pushcfunction(L, ngx_http_lua_socket_tcp_send);
    lua_setfield(L, -2, "send");
    //////////////////////////////////////////////////////////////////////
    //
    //
    //
    //             { "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send}
    //             ngx_http_lua_raw_req_socket_metatable_key
    //  1   -1     {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ....", "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}}}
    //////////////////////////////////////////////////////////////////


    lua_pushcfunction(L, ngx_http_lua_socket_tcp_settimeout);
    lua_setfield(L, -2, "settimeout"); /* ngx socket mt */

    //////////////////////////////////////////////////////////////////////
    //
    //
    //
    //             { "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send}
    //             ngx_http_lua_raw_req_socket_metatable_key
    //  1   -1     {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ....", "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}}}
    //////////////////////////////////////////////////////////////////

    lua_pushcfunction(L, ngx_http_lua_socket_tcp_settimeouts);
    lua_setfield(L, -2, "settimeouts"); /* ngx socket mt */
    //////////////////////////////////////////////////////////////////////
    //
    //             { "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send,  "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //             { "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send, ""}
    //             ngx_http_lua_raw_req_socket_metatable_key
    //  1   -1     {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ....", "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}}}
    //////////////////////////////////////////////////////////////////

    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "__index");
    //////////////////////////////////////////////////////////////////////
    //
    //
    //
    //             { "__index" = this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send,  "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //             ngx_http_lua_raw_req_socket_metatable_key
    //  1   -1     {"socket"={"tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,  "connect"="local sock ....", "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}}}
    //////////////////////////////////////////////////////////////////

    lua_rawset(L, LUA_REGISTRYINDEX);
    /* }}} */
    //////////////////////////////////////////////////////////////////////
    //
    //
    //
    //            {     "socket"={    "tcp"=ngx_http_lua_socket_tcp,"stream" = ngx_http_lua_socket_tcp,"connect"="local sock ...."}, 
    //                                "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //                                "ngx_http_lua_raw_req_socket_metatable_key"={ "__index" = this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send,  "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //                            
    //           }
    //////////////////////////////////////////////////////////////////

    /* {{{tcp object metatable */
    lua_pushlightuserdata(L, &ngx_http_lua_tcp_socket_metatable_key);
    lua_createtable(L, 0 /* narr */, 12 /* nrec */);

    lua_pushcfunction(L, ngx_http_lua_socket_tcp_connect);
    lua_setfield(L, -2, "connect");
    ///////////////////////////////////////////////////////////////
    //              
    //               {"connect"=ngx_http_lua_socket_tcp_connect}
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////
#if (NGX_HTTP_SSL)

    lua_pushcfunction(L, ngx_http_lua_socket_tcp_sslhandshake);
    lua_setfield(L, -2, "sslhandshake");
    ///////////////////////////////////////////////////////////////
    //              
    //               {"connect"=ngx_http_lua_socket_tcp_connect, "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake}
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////

#endif

    lua_pushcfunction(L, ngx_http_lua_socket_tcp_receive);
    lua_setfield(L, -2, "receive");
    ///////////////////////////////////////////////////////////////
    //              
    //               {  "connect"=ngx_http_lua_socket_tcp_connect, 
    //                  "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                  "receive"=ngx_http_lua_socket_tcp_receive
    //               }
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////

    lua_pushcfunction(L, ngx_http_lua_socket_tcp_receiveuntil);
    lua_setfield(L, -2, "receiveuntil");
    ///////////////////////////////////////////////////////////////
    //              
    //               {  "connect"=ngx_http_lua_socket_tcp_connect, 
    //                  "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                  "receive"=ngx_http_lua_socket_tcp_receive,
    //                   "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil
    //               }
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////
    lua_pushcfunction(L, ngx_http_lua_socket_tcp_send);
    lua_setfield(L, -2, "send");
    ///////////////////////////////////////////////////////////////
    //              
    //               {  "connect"=ngx_http_lua_socket_tcp_connect, 
    //                  "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                  "receive"=ngx_http_lua_socket_tcp_receive,
    //                   "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                   "send"=ngx_http_lua_socket_tcp_send
    //               }
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////
    lua_pushcfunction(L, ngx_http_lua_socket_tcp_close);
    lua_setfield(L, -2, "close");
    ///////////////////////////////////////////////////////////////
    //              
    //               {  "connect"=ngx_http_lua_socket_tcp_connect, 
    //                  "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                  "receive"=ngx_http_lua_socket_tcp_receive,
    //                   "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                   "send"=ngx_http_lua_socket_tcp_send,
    //                   "close"=ngx_http_lua_socket_tcp_close
    //               }
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////
    lua_pushcfunction(L, ngx_http_lua_socket_tcp_setoption);
    lua_setfield(L, -2, "setoption");
    ///////////////////////////////////////////////////////////////
    //              
    //               {  "connect"=ngx_http_lua_socket_tcp_connect, 
    //                  "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                  "receive"=ngx_http_lua_socket_tcp_receive,
    //                   "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                   "send"=ngx_http_lua_socket_tcp_send,
    //                   "close"=ngx_http_lua_socket_tcp_close,
    //                   "setoption"=ngx_http_lua_socket_tcp_setoption
    //               }
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////
    lua_pushcfunction(L, ngx_http_lua_socket_tcp_settimeout);
    lua_setfield(L, -2, "settimeout"); /* ngx socket mt */
    ///////////////////////////////////////////////////////////////
    //              
    //               {  "connect"=ngx_http_lua_socket_tcp_connect, 
    //                  "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                  "receive"=ngx_http_lua_socket_tcp_receive,
    //                   "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                   "send"=ngx_http_lua_socket_tcp_send,
    //                   "close"=ngx_http_lua_socket_tcp_close,
    //                   "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                   "settimeout"=ngx_http_lua_socket_tcp_settimeout
    //               }
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////
    lua_pushcfunction(L, ngx_http_lua_socket_tcp_settimeouts);
    lua_setfield(L, -2, "settimeouts"); /* ngx socket mt */
    ///////////////////////////////////////////////////////////////
    //              
    //               {  "connect"=ngx_http_lua_socket_tcp_connect, 
    //                  "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                  "receive"=ngx_http_lua_socket_tcp_receive,
    //                   "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                   "send"=ngx_http_lua_socket_tcp_send,
    //                   "close"=ngx_http_lua_socket_tcp_close,
    //                   "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                   "settimeout"=ngx_http_lua_socket_tcp_settimeout,
    //                   "settimeouts"=ngx_http_lua_socket_tcp_settimeouts
    //               }
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////
    lua_pushcfunction(L, ngx_http_lua_socket_tcp_getreusedtimes);
    lua_setfield(L, -2, "getreusedtimes");
    ///////////////////////////////////////////////////////////////
    //              
    //               {  "connect"=ngx_http_lua_socket_tcp_connect, 
    //                  "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                  "receive"=ngx_http_lua_socket_tcp_receive,
    //                   "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                   "send"=ngx_http_lua_socket_tcp_send,
    //                   "close"=ngx_http_lua_socket_tcp_close,
    //                   "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                   "settimeout"=ngx_http_lua_socket_tcp_settimeout,
    //                   "settimeouts"=ngx_http_lua_socket_tcp_settimeouts,
    //                   "getreusedtimes"=ngx_http_lua_socket_tcp_getreusedtimes
    //               }
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////
    lua_pushcfunction(L, ngx_http_lua_socket_tcp_setkeepalive);
    lua_setfield(L, -2, "setkeepalive");
    ///////////////////////////////////////////////////////////////
    //              
    //               {  "connect"=ngx_http_lua_socket_tcp_connect, 
    //                  "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                  "receive"=ngx_http_lua_socket_tcp_receive,
    //                   "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                   "send"=ngx_http_lua_socket_tcp_send,
    //                   "close"=ngx_http_lua_socket_tcp_close,
    //                   "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                   "settimeout"=ngx_http_lua_socket_tcp_settimeout,
    //                   "settimeouts"=ngx_http_lua_socket_tcp_settimeouts,
    //                   "getreusedtimes"=ngx_http_lua_socket_tcp_getreusedtimes,
    //                  "setkeepalive"=ngx_http_lua_socket_tcp_setkeepalive
    //               }
    //               ngx_http_lua_tcp_socket_metatable_key
    ////////////////////////////////////////////////////////////////
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "__index");
    lua_rawset(L, LUA_REGISTRYINDEX);
    /* }}} */

    //////////////////////////////////////////////////////////////////////
    //
    //      {  "socket"={    "tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,"connect"="local sock ...."}, 
    //         "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //         "ngx_http_lua_raw_req_socket_metatable_key"={ "__index" = this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send,  "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //          "ngx_http_lua_tcp_socket_metatable_key"=
    //                                                   { 
    //                                                        "__index"=this,
    //                                                       "connect"=ngx_http_lua_socket_tcp_connect, 
    //                                                       "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                                                       "receive"=ngx_http_lua_socket_tcp_receive,
    //                                                       "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                                                       "send"=ngx_http_lua_socket_tcp_send,
    //                                                       "close"=ngx_http_lua_socket_tcp_close,
    //                                                       "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                                                       "settimeout"=ngx_http_lua_socket_tcp_settimeout,
    //                                                       "settimeouts"=ngx_http_lua_socket_tcp_settimeouts,
    //                                                       "getreusedtimes"=ngx_http_lua_socket_tcp_getreusedtimes,
    //                                                       "setkeepalive"=ngx_http_lua_socket_tcp_setkeepalive
    //                                                    }
    //     }
    ////////////////////////////////////////////////////////////////
    /* {{{upstream userdata metatable */
    lua_pushlightuserdata(L, &ngx_http_lua_upstream_udata_metatable_key);
    lua_createtable(L, 0 /* narr */, 1 /* nrec */); /* metatable */
    lua_pushcfunction(L, ngx_http_lua_socket_tcp_upstream_destroy);
    lua_setfield(L, -2, "__gc");
    lua_rawset(L, LUA_REGISTRYINDEX);
    //////////////////////////////////////////////////////////////////////
    //
    //            {                   "socket"={    "tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,"connect"="local sock ...."}, 
    //                                "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //                                "ngx_http_lua_raw_req_socket_metatable_key"={ "__index" = this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send,  "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //                                 "ngx_http_lua_tcp_socket_metatable_key"=
    //                                                                          { 
    //                                                                               "__index"=this,
    //                                                                              "connect"=ngx_http_lua_socket_tcp_connect, 
    //                                                                              "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                                                                              "receive"=ngx_http_lua_socket_tcp_receive,
    //                                                                              "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                                                                              "send"=ngx_http_lua_socket_tcp_send,
    //                                                                              "close"=ngx_http_lua_socket_tcp_close,
    //                                                                              "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                                                                              "settimeout"=ngx_http_lua_socket_tcp_settimeout,
    //                                                                              "settimeouts"=ngx_http_lua_socket_tcp_settimeouts,
    //                                                                              "getreusedtimes"=ngx_http_lua_socket_tcp_getreusedtimes,
    //                                                                              "setkeepalive"=ngx_http_lua_socket_tcp_setkeepalive
    //                                                                           },
    //                                "ngx_http_lua_upstream_udata_metatable_key"={"__gc" = ngx_http_lua_socket_tcp_upstream_destroy}
    //          }
    ////////////////////////////////////////////////////////////////

    /* }}} */

    /* {{{downstream userdata metatable */
    lua_pushlightuserdata(L, &ngx_http_lua_downstream_udata_metatable_key);
    lua_createtable(L, 0 /* narr */, 1 /* nrec */); /* metatable */
    lua_pushcfunction(L, ngx_http_lua_socket_downstream_destroy);
    lua_setfield(L, -2, "__gc");
    lua_rawset(L, LUA_REGISTRYINDEX);
    //////////////////////////////////////////////////////////////////////
    //
    //      {  "socket"={    "tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,"connect"="local sock ...."}, 
    //         "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //         "ngx_http_lua_raw_req_socket_metatable_key"={ "__index" = this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send,  "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //          "ngx_http_lua_tcp_socket_metatable_key"=
    //                                                   { 
    //                                                        "__index"=this,
    //                                                       "connect"=ngx_http_lua_socket_tcp_connect, 
    //                                                       "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                                                       "receive"=ngx_http_lua_socket_tcp_receive,
    //                                                       "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                                                       "send"=ngx_http_lua_socket_tcp_send,
    //                                                       "close"=ngx_http_lua_socket_tcp_close,
    //                                                       "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                                                       "settimeout"=ngx_http_lua_socket_tcp_settimeout,
    //                                                       "settimeouts"=ngx_http_lua_socket_tcp_settimeouts,
    //                                                       "getreusedtimes"=ngx_http_lua_socket_tcp_getreusedtimes,
    //                                                       "setkeepalive"=ngx_http_lua_socket_tcp_setkeepalive
    //                                                    },
    //         "ngx_http_lua_upstream_udata_metatable_key"={"__gc" = ngx_http_lua_socket_tcp_upstream_destroy}
    //         "ngx_http_lua_downstream_udata_metatable_key"={"__gc" = ngx_http_lua_socket_downstream_destroy}
    //       }
    ////////////////////////////////////////////////////////////////
    /* }}} */

    /* {{{socket pool userdata metatable */
    lua_pushlightuserdata(L, &ngx_http_lua_pool_udata_metatable_key);
    lua_createtable(L, 0, 1); /* metatable */
    lua_pushcfunction(L, ngx_http_lua_socket_shutdown_pool);
    lua_setfield(L, -2, "__gc");
    lua_rawset(L, LUA_REGISTRYINDEX);
    //////////////////////////////////////////////////////////////////////
    //
    //      {  "socket"={    "tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,"connect"="local sock ...."}, 
    //         "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //         "ngx_http_lua_raw_req_socket_metatable_key"={ "__index" = this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send,  "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //          "ngx_http_lua_tcp_socket_metatable_key"=
    //                                                   { 
    //                                                        "__index"=this,
    //                                                       "connect"=ngx_http_lua_socket_tcp_connect, 
    //                                                       "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                                                       "receive"=ngx_http_lua_socket_tcp_receive,
    //                                                       "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                                                       "send"=ngx_http_lua_socket_tcp_send,
    //                                                       "close"=ngx_http_lua_socket_tcp_close,
    //                                                       "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                                                       "settimeout"=ngx_http_lua_socket_tcp_settimeout,
    //                                                       "settimeouts"=ngx_http_lua_socket_tcp_settimeouts,
    //                                                       "getreusedtimes"=ngx_http_lua_socket_tcp_getreusedtimes,
    //                                                       "setkeepalive"=ngx_http_lua_socket_tcp_setkeepalive
    //                                                    },
    //         "ngx_http_lua_upstream_udata_metatable_key"={"__gc" = ngx_http_lua_socket_tcp_upstream_destroy}
    //         "ngx_http_lua_downstream_udata_metatable_key"={"__gc" = ngx_http_lua_socket_downstream_destroy}
    //         "ngx_http_lua_pool_udata_metatable_key"={"__gc" = ngx_http_lua_socket_shutdown_pool}
    //       }
    ////////////////////////////////////////////////////////////////
    /* }}} */

    /* {{{socket compiled pattern userdata metatable */
    lua_pushlightuserdata(L, &ngx_http_lua_pattern_udata_metatable_key);
    lua_createtable(L, 0 /* narr */, 1 /* nrec */); /* metatable */
    lua_pushcfunction(L, ngx_http_lua_socket_cleanup_compiled_pattern);
    lua_setfield(L, -2, "__gc");
    lua_rawset(L, LUA_REGISTRYINDEX);
   //////////////////////////////////////////////////////////////////////
    //
    //      {  "socket"={    "tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,"connect"="local sock ...."}, 
    //         "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //         "ngx_http_lua_raw_req_socket_metatable_key"={ "__index" = this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send,  "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //          "ngx_http_lua_tcp_socket_metatable_key"=
    //                                                   { 
    //                                                        "__index"=this,
    //                                                       "connect"=ngx_http_lua_socket_tcp_connect, 
    //                                                       "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                                                       "receive"=ngx_http_lua_socket_tcp_receive,
    //                                                       "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                                                       "send"=ngx_http_lua_socket_tcp_send,
    //                                                       "close"=ngx_http_lua_socket_tcp_close,
    //                                                       "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                                                       "settimeout"=ngx_http_lua_socket_tcp_settimeout,
    //                                                       "settimeouts"=ngx_http_lua_socket_tcp_settimeouts,
    //                                                       "getreusedtimes"=ngx_http_lua_socket_tcp_getreusedtimes,
    //                                                       "setkeepalive"=ngx_http_lua_socket_tcp_setkeepalive
    //                                                    },
    //         "ngx_http_lua_upstream_udata_metatable_key"={"__gc" = ngx_http_lua_socket_tcp_upstream_destroy},
    //         "ngx_http_lua_downstream_udata_metatable_key"={"__gc" = ngx_http_lua_socket_downstream_destroy},
    //         "ngx_http_lua_pool_udata_metatable_key"={"__gc" = ngx_http_lua_socket_shutdown_pool},
    //         "ngx_http_lua_pattern_udata_metatable_key"={"__gc" = ngx_http_lua_socket_cleanup_compiled_pattern}
    //       }
    ////////////////////////////////////////////////////////////////
    /* }}} */

#if (NGX_HTTP_SSL)

    /* {{{ssl session userdata metatable */
    lua_pushlightuserdata(L, &ngx_http_lua_ssl_session_metatable_key);
    lua_createtable(L, 0 /* narr */, 1 /* nrec */); /* metatable */
    lua_pushcfunction(L, ngx_http_lua_ssl_free_session);
    lua_setfield(L, -2, "__gc");
    lua_rawset(L, LUA_REGISTRYINDEX);
   //////////////////////////////////////////////////////////////////////
    //
    //      {  "socket"={    "tcp"=ngx_http_lua_socket_tcp, "stream" = ngx_http_lua_socket_tcp,"connect"="local sock ...."}, 
    //         "ngx_http_lua_req_socket_metatable_key" = {"__index"=this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_settimeout, "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //         "ngx_http_lua_raw_req_socket_metatable_key"={ "__index" = this, "receive"=ngx_http_lua_socket_tcp_receive, "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil, "settimeout"=ngx_http_lua_socket_tcp_send,  "settimeouts"=ngx_http_lua_socket_tcp_settimeouts}
    //          "ngx_http_lua_tcp_socket_metatable_key"=
    //                                                   { 
    //                                                        "__index"=this,
    //                                                       "connect"=ngx_http_lua_socket_tcp_connect, 
    //                                                       "sslhandshake"=ngx_http_lua_socket_tcp_sslhandshake, 
    //                                                       "receive"=ngx_http_lua_socket_tcp_receive,
    //                                                       "receiveuntil"=ngx_http_lua_socket_tcp_receiveuntil,
    //                                                       "send"=ngx_http_lua_socket_tcp_send,
    //                                                       "close"=ngx_http_lua_socket_tcp_close,
    //                                                       "setoption"=ngx_http_lua_socket_tcp_setoption,
    //                                                       "settimeout"=ngx_http_lua_socket_tcp_settimeout,
    //                                                       "settimeouts"=ngx_http_lua_socket_tcp_settimeouts,
    //                                                       "getreusedtimes"=ngx_http_lua_socket_tcp_getreusedtimes,
    //                                                       "setkeepalive"=ngx_http_lua_socket_tcp_setkeepalive
    //                                                    },
    //         "ngx_http_lua_upstream_udata_metatable_key"={"__gc" = ngx_http_lua_socket_tcp_upstream_destroy},
    //         "ngx_http_lua_downstream_udata_metatable_key"={"__gc" = ngx_http_lua_socket_downstream_destroy},
    //         "ngx_http_lua_pool_udata_metatable_key"={"__gc" = ngx_http_lua_socket_shutdown_pool},
    //         "ngx_http_lua_pattern_udata_metatable_key"={"__gc" = ngx_http_lua_socket_cleanup_compiled_pattern},
    //         "ngx_http_lua_ssl_session_metatable_key"={"__gc" = ngx_http_lua_ssl_free_session}
    //       }
    ////////////////////////////////////////////////////////////////
    /* }}} */

#endif
}