apache 通过urlrewrite防盗链功能配置

配置虚拟主机时，在配置文件中加入如下内容 

      DocumentRoot /home/img
      ServerName img.host.com
      ErrorDocument 404 /
      RewriteEngine on
      RewriteCond %{HTTP_REFERER} !^$
      RewriteCond %{HTTP_REFERER} !^http://img.host.com/.*$ [NC]
      RewriteCond %{HTTP_REFERER} !^http://www.host.com/.*$ [NC]
      RewriteRule \.(gif|jpg|jpeg)$ http://img.host.com/forbidden.png [R,L]