语法: str = ngx.today()
环境: init_worker_by_lua*, set_by_lua*, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.*
从nginx的时间缓存(不像Lua的日期库，该时间不涉及系统调用)返回当前的日期(格式：yyyy-mm-dd)。
这是个本地时间。
English Source
syntax: str = ngx.today()
context: init_worker_by_lua*, set_by_lua*, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.*
Returns current date (in the format yyyy-mm-dd) from the nginx cached time (no syscall involved unlike Lua's date library).
This is the local time.