How do I get the avatar through QQ email?

You may find out that once you comment with your QQ email, this website can get your QQ avatar.

Only QQ email is supported, maybe more email can be done in the future. :)

How did I do this? Check out this code:

<?php
    //Get email address
    $s1 = $_GET["n1"];
    //md5 encode
    $mdmd5 = md5(strtolower(trim($s1)));
    $qqnum = str_replace('@qq.com', '', $s1);
    if (strstr($s1,"qq.com") && is_numeric($qqnum) && strlen($qqnum) > 4 && strlen($qqnum) < 12) {
        $avatar = 'https://q2.qlogo.cn/g?b=qq&nk='.$qqnum.'&s=100';
    }else {
        $avatar = 'https://cdn.v2ex.com/gravatar/' . $mdmd5 . '?s=80';
    }
    //output the avatar
    echo "<img style='width:80px;height:80px;' src='".$avatar."'>";
?>