Helper\Utils::gravatar PHP Method

    public static function gravatar($email, $s = 128, $d = 'mm', $r = 'g', $img = false, $atts = array())
    {
        $host = array('//cdn.v2ex.co/gravatar/');
        // 前三个支持https
        $url = $host[0];
        $url .= md5(strtolower(trim($email)));
        $url .= "?s={$s}&d={$d}&r={$r}";
        if ($img) {
            $url = '<img src="' . $url . '"';
            foreach ($atts as $key => $val) {
                $url .= ' ' . $key . '="' . $val . '"';
            }
            $url .= ' />';
        }
        return $url;
    }

 /**
  * 对邮件占位符进行替换
  * 支持：
  * <pre>
  *      {SITE_NAME} : 站点名称
  *      {nickname}  : 当前用户名称
  *      {email}     : 用户电子邮件
  *      {code}      : 验证码
  *      {newPassword}: 新密码
  *      {useTraffic}: 已用流量
  *      {transfer}  : 总流量
  *      {expireTime}: 到期时间
  *      {avatar}:     用户头像 (必须与 {email} 同时使用)
  *      {REGISTER_URL}: 注册校验链接
  * </pre>
  * @param $content
  * @param $params array
  * @return string
  */
 public static function placeholderReplace($content, $params)
 {
     if ($params['REGISTER_URL'] != null) {
         $url = BASE_URL . 'auth/verification?verification=' . urlencode($params['REGISTER_URL']);
         $params['REGISTER_URL'] = "<a href=\"{$url}\" target=\"_blank\" title=\"点击校验您的账户并完成注册！\">{$url}</a>";
     }
     if ($params['avatar'] === true) {
         $params['avatar'] = Utils::gravatar($params['email']);
     }
     // 替换
     $content = str_replace(['{SITE_NAME}', '{nickname}', '{email}', '{code}', '{newPassword}', '{useTraffic}', '{transfer}', '{expireTime}', '{REGISTER_URL}', '{avatar}'], [SITE_NAME, $params['nickname'], $params['email'], $params['code'], $params['newPassword'], $params['useTraffic'], $params['transfer'], $params['expireTime'], $params['REGISTER_URL'], $params['avatar']], $content);
     return $content;
 }