海运的博客

#centos6：
rpm -ivh http://nginx.org/packages/centos/6/noarch/RPMS/nginx-release-centos-6-0.el6.ngx.noarch.rpm
#centos5：
rpm -ivh http://nginx.org/packages/centos/5/noarch/RPMS/nginx-release-centos-5-0.el5.ngx.noarch.rpm

或自添加：

[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/6/$basearch/
gpgcheck=0
enabled=1

Nginx与PHP通信使用TCP连接会造成太多TIME_WAIT及浪费新建连接开销，Nginx新版本增加了对后端启用keepalive功能，有效提高服务器性能。
配置：

http
{
    upstream fastcgi_backend {
    server 127.0.0.1:9000;
    keepalive 60;
    }
}
server
{
  location ~ .*\.php$
  {
    fastcgi_pass fastcgi_backend;
    fastcgi_keep_conn on;
  }
}

不能提取com.cn类似的域名：

<?php
   $url = 'https://www.haiyun.me';
   $host = parse_url($url, PHP_URL_HOST);
   $host_parts = explode('.', $host);
   $domain = implode('.', array_slice($host_parts, count($host_parts)-2));
   echo $domain;
?>

<?php
   $url = 'https://www.haiyun.me';
   $host = parse_url($url, PHP_URL_HOST);
   $host_parts = explode('.', $host);
   if(count($host_parts) > 2) {
      $host_parts = array_reverse($host_parts);
      $domain = $host_parts[1].'.'.$host_parts[0];
   } else {
      $domain = $host;
   }
   echo $domain;
?>

正则，www.hai.me被认为是根域名：

<?php
   function get_domain($url)
   {
      $domain = parse_url($url, PHP_URL_HOST);
      if (preg_match('/(?P<domain>[a-z0-9][a-z0-9\-]{1,63}\.[a-z\.]{2,6})$/i', $domain, $regs)) {
         var_dump($regs);
         return $regs['domain'];
      }
      return false;
   }

   echo get_domain("https://www.haiyun.me");
?>

基于tld列表，精确：
https://publicsuffix.org/learn/