nginx+lua 缓存html文件到本地

官方：
github.com/akin520/nginx_cache_file/
配置如下：

server {
    listen 443;                        # 监听端口
    server_name m.demo.cn;    # 站点域名
    root  /xq_data/xq_web/demo/;              # 站点根目录
    index index.html index.htm index.php;   # 默认导航页


    ssl on;
    ssl_certificate demo.cn.crt;
    ssl_certificate_key demo.cn.key;

    access_log  /var/log/nginx_logs/m-cache.log  main;

    set $proxy "";

    location / {
        default_type    text/html;
        if ($request_method = PURGE) {
            content_by_lua '
                local request_uri = ngx.var.request_uri;
                local tmp_file = string.gsub(request_uri,"/","_")
                local cache_file = string.gsub(tmp_file,"&","*")
                local cmd = "rm -rf /xq_data/cache/"..ngx.var.host.."/"..cache_file .. " 2>&1"
                os.execute(cmd)
                --- clear only key
                local md5 = ngx.md5
                local key = md5(request_uri)
                local cache_ngx = ngx.shared.my_cache
                cache_ngx:delete(key)
                ngx.header["Content-type"] = "text/plain; charset=utf-8"
                ngx.header["X-Purged-Count"] = "clear"
                ngx.header["X-CMD"] = cmd
                ngx.say("OK")
            ';
        }
        content_by_lua_file /usr/local/nginx/vhost/cache_file.lua;
        }

        location = /m_404.html {
            root /xq_data/xq_web/demo/demo;
        }

        error_page 404 /m_404.html;
}