在百度搜索文章的时候，发现自己站内的一篇老文章已经打不开了，提示了用户页面不存在，出现的是 404 的页面，紧急做了处理，如果是访客访问这样的页面出现提示就感觉不好了，而作为懒人的我又不愿意去看服务器的日志，所以懒人就用懒人的方法吧，在网上找了一段这样的代码，就是当有人访问网站出现 404 页面的时候就给我发一封邮件进行通知，这样看到通知后就可以去处理 404 的页面了。实例代码如下:

<?php
  
// 发出404状态码
header("HTTP/1.1 404 Not Found");
header("Status: 404 Not Found");
  
// 网站信息
$blog  = get_bloginfo('name');
$site  = get_bloginfo('url') . '/';
$email = get_bloginfo('admin_email');
  
// 当前主题信息
if (!empty($_COOKIE&#91;"nkthemeswitch" . COOKIEHASH&#93;)) {
    $theme = clean($_COOKIE&#91;"nkthemeswitch" . COOKIEHASH&#93;);
} else {
    $theme_data = wp_get_theme();
    $theme = clean($theme_data->Name);
}
  
// 访问404页面的访客
if (isset($_SERVER['HTTP_REFERER'])) {
    $referer = clean($_SERVER['HTTP_REFERER']);
} else {
    $referer = "undefined";
}
// 请求的URL
if (isset($_SERVER['REQUEST_URI']) && isset($_SERVER["HTTP_HOST"])) {
    $request = clean('http://' . $_SERVER["HTTP_HOST"] . $_SERV
ER["REQUEST_URI"]);
} else {
    $request = "undefined";
}
// 查询字符串
if (isset($_SERVER['QUERY_STRING'])) {
    $string = clean($_SERVER['QUERY_STRING']);
} else {
    $string = "undefined";
}
// IP地址
if (isset($_SERVER['REMOTE_ADDR'])) {
    $address = clean($_SERVER['REMOTE_ADDR']);
} else {
    $address = "undefined";
}
//用户代理
if (isset($_SERVER['HTTP_USER_AGENT'])) {
    $agent = clean($_SERVER['HTTP_USER_AGENT']);
} else {
    $agent = "undefined";
}
//身份
if (isset($_SERVER['REMOTE_IDENT'])) {
    $remote = clean($_SERVER['REMOTE_IDENT']);
} else {
    $remote = "undefined";
}
//日志时间
$time = clean(date("F jS Y, h:ia", time()));
  
function clean($string) {
    $string = rtrim($string);
    $string = ltrim($string);
    $string = htmlentities($string, ENT_QUOTES);
    $string = str_replace("\n", "<br>", $string);
  
    if (get_magic_quotes_gpc()) {
        $string = stripslashes($string);
    }
    return $string;
}
  
$message =
    "TIME: "            . $time    . "\n" .
    "*404: "            . $request . "\n" .
    "SITE: "            . $site    . "\n" .
    "THEME: "           . $theme   . "\n" .
    "REFERRER: "        . $referer . "\n" .
    "QUERY STRING: "    . $string  . "\n" .
    "REMOTE ADDRESS: "  . $address . "\n" .
    "REMOTE IDENTITY: " . $remote  . "\n" .
    "USER AGENT: "      . $agent   . "\n\n\n";
  
mail($email, "404 Alert: " . $blog . " [" . $theme . "]", $messa
ge, "From: $email");
  
?>

前提你的站点支持 mail 的函数，可以正常发送邮件，否则是收不到邮件的，在主题下的 404.php 中加上如上的代码即可。