应用场景：为减少源站流量，我们可以永久缓存用户的头像，只在用户上传新头像时，才刷新CDN服务器上的缓存。

本文案例中的CDN服务器环境如下，仅供参考：
Nginx，已安装 cache-purge 扩展，通过请求 $host/purge/$uri 的方式清除缓存。所使用的域名与源站一致。

1、首先在CDN服务器中配置清除规则，将源站服务器IP设置为允许；

2、打开 uc_server/data/config.inc.php ，在末尾加入CDN服务器的IP地址，便于统一调用和修改。

define('UC_CDNIP', '123.123.123.123');

3、打开 uc_server/control/user.php ，添加上传头像后自动清除CDN缓存的功能。

查找：

<p>

</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>$bigavatarfile = UC_DATADIR.'./avatar/'.$this->get_avatar($uid, 'big', $avatartype);</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>$middleavatarfile = UC_DATADIR.'./avatar/'.$this->get_avatar($uid, 'middle', $avatartype);</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>$smallavatarfile = UC_DATADIR.'./avatar/'.$this->get_avatar($uid, 'small', $avatartype);</p>

替换为：

<p>

</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>$getavatar_big = $this->get_avatar($uid, 'big', $avatartype);</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>$getavatar_middle = $this->get_avatar($uid, 'middle', $avatartype);</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>$getavatar_small = $this->get_avatar($uid, 'small', $avatartype);</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>$bigavatarfile = UC_DATADIR.'./avatar/'.$getavatar_big;</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>$middleavatarfile = UC_DATADIR.'./avatar/'.$getavatar_middle;</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>$smallavatarfile = UC_DATADIR.'./avatar/'.$getavatar_small;</p>

这一步是取得头像路径。接下来查找：

<span class="Apple-tab-span" style="white-space:pre">		</span>return '<?xml version="1.0" ?><root><face success="1"/></root>';

在前方加入：

<p><span class="Apple-tab-span" style="white-space:pre">			</span>$uccdnip = UC_CDNIP; //在 data/config.inc.php 中设置UC的CDN服务器IP，用于通知刷新头像</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>$avatarurl = 'https://'.$uccdnip.'/purge/data/avatar/';</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>$uchostname = stream_context_create(array('http' => array('header' => 'Host: '.$_SERVER['SERVER_NAME'])));</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_get_contents($avatarurl.$getavatar_big, NULL, $uchostname);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_get_contents($avatarurl.$getavatar_middle, NULL, $uchostname);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_get_contents($avatarurl.$getavatar_small, NULL, $uchostname);</p>

上传覆盖即可。

附：若你要在用户上传头像后点击“完成”时自动刷新头像上传页面，按照以下教程操作：
在 home/spacecp_avatar.htm 模板中查找：

<p><span class="Apple-tab-span" style="white-space:pre">		</span>if(redirecturl) {</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>$('retpre').innerHTML = '<a href="' + redirecturl + '">{lang previous_page}</a>';</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>}</p>

在其下方新增：

<p><span class="Apple-tab-span" style="white-space:pre">		</span>function updateavatar() {  </p><p><span class="Apple-tab-span" style="white-space:pre">			</span>window.location.reload();  </p><p><span class="Apple-tab-span" style="white-space:pre">		</span>}</p>

上传并更新缓存即可。


4、管理员清除头像时，同步清除CDN服务器上的头像缓存。

打开 uc_server/model/user.php ，查找：

<p><span class="Apple-tab-span" style="white-space:pre">		</span>foreach((array)$uidsarr as $uid) {</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'big', 'real')) && unlink($avatar_file);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'middle', 'real')) && unlink($avatar_file);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'small', 'real')) && unlink($avatar_file);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'big')) && unlink($avatar_file);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'middle')) && unlink($avatar_file);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'small')) && unlink($avatar_file);</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>}</p>

替换为：

$uccdnip = UC_CDNIP; //在 data/config.inc.php 中设置UC的CDN服务器IP，用于通知刷新头像

<p><span class="Apple-tab-span" style="white-space:pre">		</span>$uchostname = stream_context_create(array('http' => array('header' => 'Host: '.$_SERVER['SERVER_NAME'])));</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>foreach((array)$uidsarr as $uid) {</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'big', 'real')) && unlink($avatar_file) && file_get_contents(str_replace(UC_DATADIR.'./','https://'.$uccdnip.'/purge/data/',$avatar_file), NULL, $uchostname);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'middle', 'real')) && unlink($avatar_file) && file_get_contents(str_replace(UC_DATADIR.'./','https://'.$uccdnip.'/purge/data/',$avatar_file), NULL, $uchostname);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'small', 'real')) && unlink($avatar_file) && file_get_contents(str_replace(UC_DATADIR.'./','https://'.$uccdnip.'/purge/data/',$avatar_file), NULL, $uchostname);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'big')) && unlink($avatar_file) && file_get_contents(str_replace(UC_DATADIR.'./','https://'.$uccdnip.'/purge/data/',$avatar_file), NULL, $uchostname);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'middle')) && unlink($avatar_file) && file_get_contents(str_replace(UC_DATADIR.'./','https://'.$uccdnip.'/purge/data/',$avatar_file), NULL, $uchostname);</p><p><span class="Apple-tab-span" style="white-space:pre">			</span>file_exists($avatar_file = UC_DATADIR.'./avatar/'.$this->base->get_avatar($uid, 'small')) && unlink($avatar_file) && file_get_contents(str_replace(UC_DATADIR.'./','https://'.$uccdnip.'/purge/data/',$avatar_file), NULL, $uchostname);</p><p><span class="Apple-tab-span" style="white-space:pre">		</span>}</p>

上传覆盖即可。