ngx.arg[1]?? ??? ??? ??? ?脚本参数
 ngx.var['arg_a']?? ??? ??? ?取queryString的参数a #/nginx_var?a=hello,world
 ngx.say(...)?? ??? ??? ??? ?依次输出参数,带换行
 ngx.print(...)?? ??? ??? ??? ?格式化输出,不带换行
 ngx.var.name?? ??? ??? ??? ?取nginx里的name变量,如ngx.var.remote_addr
 locale res = ngx.location.capture()?? ?请求内部location
 ngx.location.capture_multi()?? ??? ?同时请求多个内部location
 res.status?? ??? ??? ??? ?取上面请求返回的状态
 ?? ?取值为常量:
 ?? ?ngx.HTTP_OK = 200
 ?? ?ngx.HTTP_FORBIDDEN
 ?? ?ngx.HTTP_INTERNAL_SERVER_ERROR
 ?? ?... ...
 res.body?? ??? ??? ??? ?去上面请求反回的页面内容
 ngx.exec(uri,args?)?? ??? ??? ?内部重定向
 ngx.exit(ngx.HTTP_FORBIDDEN)?? ??? ?退出执行并返回状态常量值
 ngx.redirect(uri,status?)?? ??? ?301/302重定向
 ?? ?rewrite ^ /foo? redirect; ?# nginx config
 ?? ?等价于
 ?? ?return ngx.redirect('/foo'); ?-- Lua code
 
 ?? ?rewrite ^ /foo? permanent; ?# nginx config
 ?? ?等价于
 ?? ?return ngx.redirect('/foo',ngx.HTTP_MOVED_PERMANENTLY) ?-- Lua code
 ngx.send_headers()?? ??? ??? ?明确地发送response headers
 ngx.headers_sent?? ??? ??? ?用此变量标识response headers是否已发送
 ngx.log(log_level,...)?? ??? ??? ?记录参数到error.log
 ngx.flush()?? ??? ??? ??? ?把response输出到客户端
 ngx.eof()?? ??? ??? ??? ?明确指定response输出流结束
 ngx.sleep(seconds)?? ??? ??? ?非阻塞sleep指定秒(应该是指协程短期不调度)
 ngx.escape_uri(str)?? ??? ??? ?url转义
 ngx.unescape_uri(str)?? ??? ??? ?url转义还原
 ngx.encode_args()?? ??? ??? ?把lua table编码为查询参数字符串
 ngx.decode_args(str,max_args?)?? ??? ?把查询字符串转为lua table
 ngx.encode_base64(str)?? ??? ??? ?base64编码
 ngx.decode_base64(str)?? ??? ??? ?base64解码
 ngx.crc32_short(str)?? ??? ??? ?crc32 小于30~60字节更高效
 ngx.crc32_long(str)?? ??? ??? ?crc32 大于30~60字节更高效
 ngx.hmac_sha1(secret_key,str)?? ??? ?HMAC-SHA1
 ngx.md5(str)?? ??? ??? ??? ?md5
 ngx.md5_bin(str)?? ??? ??? ?bin 格式 md5
 ngx.sha1_bin(str)?? ??? ??? ?bin 格式 sha1
 ngx.quote_sql_str(raw_val)?? ??? ?Returns a quoted SQL string literal according to the MySQL quoting rules.?? ?ngx.today()?? ??? ??? ??? ?ngx缓存当前本地日期
 ngx.time()?? ??? ??? ??? ?从nginx当前缓存时间戳经过的秒数
 ngx.now()?? ??? ??? ??? ?同上,但返回浮点数,单位也是秒
 ngx.update_time()?? ??? ??? ?强制更新nginx当前时间缓存。系统调用勿滥用
 ngx.localtime()?? ??? ??? ??? ?返回nginx当前时间缓存,本地时间,格式yyyy-mm-dd hh:mm:ss
 ngx.utctime()?? ??? ??? ??? ?同上,但为utc时间
 ngx.cookie_time(sec)?? ??? ??? ?返回格式化后的字符串,可以用作cookie过期时间
 ngx.http_time(sec)?? ??? ??? ?返回格式化后的字符串,可以用作http头时间,如Last-Modified
 ngx.parse_http_time(str)?? ??? ?上面的反操作
 ngx.is_subrequest?? ??? ??? ?当前req如果是nginx subrequest,则为true
 captures,err = ngx.re.match(subject,regex,options?,ctx?,res_table?) ?? ??? ?正则匹配
 from,to,err = ngx.re.find(subject,nth?)?? ??? ??? ??? ?同上,但是返回匹配的起始和结束位置
 iterator,err = ngx.re.gmatch(subject,options?)?? ??? ??? ??? ??? ??? ??? ?同上上,但返回的是lua iterator,可遍历所有匹配
 newstr,n,err = ngx.re.sub(subject,replace,options?)?? ??? ??? ??? ??? ?正则匹配并替换
 newstr,err = ngx.re.gsub(subject,options?)?? ??? ??? ??? ??? ?同上,但是是全局替换
 dict = ngx.shared.DICT?? ??? ??? ??? ?访问lua_shared_dict定义的共享内存lua字典
 dict = ngx.shared[name_var]
 ?? ?get?? ??? ??? ??? ??? ?例如value,flags = ngx.shared.DICT:get(key)
 ?? ?get_stale?? ??? ??? ?即时过期也返回数据
 ?? ?set?? ??? ??? ??? ??? ?例如success,err,forcible = ngx.shared.DICT:set(key,value,exptime?,flags?)
 ?? ?safe_set?? ??? ??? ?内存不够也不覆盖未过期数据
 ?? ?add?? ??? ??? ??? ??? ?同set,但只当key不存在时存
 ?? ?safe_add?? ??? ??? ?同add,但即使内存不够也不覆盖未过期数据
 ?? ?replace?? ??? ??? ??? ?同set,但只当key存在时存储
 ?? ?delete?? ??? ??? ??? ?无条件移除
 ?? ?incr?? ??? ??? ??? ?按指定步长增加数字值
 ?? ?flush_all?? ??? ??? ?清洗所有数据,不释放空间,只标记过期
 ?? ?flush_expired?? ??? ?清晰过期数据
 ?? ?get_keys?? ??? ??? ?获取指定数量的key列表
 udpsock = ngx.socket.udp()
 ?? ?setpeername?? ??? ??? ??? ?ok,err = udpsock:setpeername(host,port),ok,err = udpsock:setpeername("unix:/path/to/unix-domain.socket")
 ?? ?send
 ?? ?receive
 ?? ?close
 ?? ?settimeout
 tcpsock = ngx.socket.tcp()
 ?? ?connect
 ?? ?sslhandshake
 ?? ?send
 ?? ?receive
 ?? ?close
 ?? ?settimeout
 ?? ?setoption
 ?? ?receiveuntil
 ?? ?setkeepalive
 ?? ?getreusedtimes
 tcpsock,err = ngx.socket.connect(host,port)
 tcpsock,err = ngx.socket.connect("unix:/path/to/unix-domain.socket")
 str = ngx.get_phase() ? ? //nginx当前处于哪个处理阶段
 ?? ?init
 ?? ?for the context of init_by_lua or init_by_lua_file.
 ?? ?set
 ?? ?for the context of set_by_lua or set_by_lua_file.
 ?? ?rewrite
 ?? ?for the context of rewrite_by_lua or rewrite_by_lua_file.
 ?? ?access
 ?? ?for the context of access_by_lua or access_by_lua_file.
 ?? ?content
 ?? ?for the context of content_by_lua or content_by_lua_file.
 ?? ?header_filter
 ?? ?for the context of header_filter_by_lua or header_filter_by_lua_file.
 ?? ?body_filter
 ?? ?for the context of body_filter_by_lua or body_filter_by_lua_file.
 ?? ?log
 ?? ?for the context of log_by_lua or log_by_lua_file.
 ?? ?timer
 ?? ?for the context of user callback functions for ngx.timer.*.
 co = ngx.thread.spawn(func,arg1,arg2,...)
 ok,res1,res2,... = ngx.thread.wait(thread1,thread2,err = ngx.thread.kill(thread)
 ok,err = ngx.on_abort(callback)?? ??? ??? ??? ??? ??? ??? ??? ??? ?//注册回调函数,当客户端断开链接时执行
 ok,err = ngx.timer.at(delay,callback,user_arg1,user_arg2,...) ?//定时执行(一次)
 debug = ngx.config.debug?? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ?//标识nginx是不是debug build
 prefix = ngx.config.prefix()?? ??? ??? ??? ??? ??? ??? ??? ??? ??? ?//nginx "prefix"路径
 ver = ngx.config.nginx_version
 str = ngx.config.nginx_configure()?? ??? ??? ??? ??? ??? ??? ??? ??? ?//返回编译时./configure的参数
 ver = ngx.config.ngx_lua_version
 exiting = ngx.worker.exiting()?? ??? ??? ??? ??? ??? ??? ??? ??? ??? ?//boolean值表示是否已经开始退出
 pid = ngx.worker.pid()?? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ?//当前nginx worker进程id,比ngx.var.pid更高效,可用面更广
 res = ndk.set_var.DIRECTIVE_NAME?? ??? ??? ??? ??? ??? ??? ??? ??? ?//通过ndk的set_var调用ngx的其他C模块,安全相关
 ?? ?set_quote_sql_str
 ?? ?set_quote_pgsql_str
 ?? ?set_quote_json_str
 ?? ?set_unescape_uri
 ?? ?set_escape_uri
 ?? ?set_encode_base32
 ?? ?set_decode_base32
 ?? ?set_encode_base64
 ?? ?set_decode_base64
 ?? ?set_encode_hex
 ?? ?set_decode_hex
 ?? ?set_sha1
 ?? ?set_md5
 
 ?? ?set_encrypt_session
 ?? ?set_decrypt_session
 co = coroutine.create(f)?? ??? ??? ??? ??? ?//创建协程
 ok,... = coroutine.resume(co,...)?? ??? ??? ?//唤醒(切换到)协程
 ... = coroutine.yield(...)?? ??? ??? ??? ??? ?//切换回调用协程
 co = coroutine.wrap(f)?? ??? ??? ??? ??? ??? ?//创建新协程,返回一个方法,每次调用唤醒协程,函数参数作为resume的额外参数
 co = coroutine.running()?? ??? ??? ??? ??? ?//返回正在运行的coroutine,如果是main thread则返回nil
 status = coroutine.status(co)?? ??? ??? ??? ?//返回协程co的状态
 ?? ?running
 ?? ?suspended?? ??? ??? ?//yield
 ?? ?normal?? ??? ??? ??? ?//激活但没运行,也就是它唤醒了另一个协程
 ?? ?dead?? ??? ??? ??? ?//完成了它的函数体执行或已遇到错误停止
 
 ?
 
 redis2_query ?? ?set key val ? ? ? ? ? ? ? ?赋值 ?成功显示 +OK ?? ?get key ? ? ? ? ? ? ? ? ? ?取值 ?成功返回 $长度 值 ?如"$3 abc" ?? ?lpush key val [val ...] ? ?将一个或多个值 value 插入到列表 key 的表头 ? ? ? ? ? ? ? ? ? ? ? ? ? LPUSH key value [value ...] ?? ?lrange key start stop ? ? ?返回列表 key 中指定区间内的元素,区间以偏移量 start 和 stop 指定。 ? LRANGE key start stop redis2_pass?? ??? ??? ??? ??? ??? ?指定redis服务器 redis2_literal_raw_query ?? ??? ?不能使用ngx变量,也就是你可以自由使用$字符 redis2_raw_query ?? ??? ??? ??? ?raw查询 redis2_raw_queries?? ??? ??? ??? ?可以处理多个raw_query,如redis2_raw_queries 3 "flushallrnget key1rnget key2rn"; redis2_connect_timeout?? ??? ??? ?设置连接redis服务器超时,单位秒 redis2_send_timeout?? ??? ??? ??? ?发送tcp请求到redis服务器的超时时间 redis2_read_timeout?? ??? ??? ??? ?从redis服务器读取tcp响应超时时间 redis2_buffer_size?? ??? ??? ??? ?redis回复缓存,但不需要像可能的最大redis回复那么大,默认值同页面大小,可能是4k或8k redis2_next_upstream?? ??? ??? ?指定哪些失败条件可以导致请求转发到另一个upstream服务器