Openresty 学习笔记（二）Nginx Lua 正则表达式相关API

ngx.re.match

语法: captures, err = ngx.re.match(subject, regex, options?, ctx?, res_table?)

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.*, balancer_by_lua*, ssl_certificate_by_lua*, ssl_session_fetch_by_lua*, ssl_session_store_by_lua*

更多详解

官方的DEMO

local m, err = ngx.re.match("hello, 1234", "[0-9]+")
 if m then
     -- m[0] == "1234"

 else
     if err then
         ngx.log(ngx.ERR, "error: ", err)
         return
     end

     ngx.say("match not found")
 end

从URL地址中获取域名，脚本：ngx-re-match.lua

local m, err = ngx.re.match("http://www.tinywan.com/live", "(?<=://)[A-Za-z0-9.]+(?=/)")
    if m then
        -- m[0] == "1234"
        ngx.say(m[0])
        ngx.say(m[1])
    else
        if err then
            ngx.log(ngx.ERR, "error: ", err)
            return
        end

        ngx.say("match not found")
    end
    ngx.say('finished')

虚拟主机：

server {
        listen 8334;
        server_name  127.0.0.1;
        resolver 8.8.8.8;

        location /ngx_re_match {
             lua_code_cache off;
             content_by_lua_file $path/lua/ngx-re-match.lua;
         }
    }

curl 请求结果：

curl http://127.0.0.1:8334/ngx_re_match
www.tinywan.com
nil
finished

如果想获取一级域名：tinywan.com 请使用表达式：

(?<=://w{5}.)[A-Za-z0-9.]+(?=/)