PHP 防止 E-mail 注入
防止 e-mail 注入的最好方法是对输入进行验证。
下面的代码与上一节类似，不过我们已经增加了检测表单中 email 字段的输入验证程序：
<html>
<body>
<?php
function spamcheck($field)
{
//filter_var() sanitizes the e-mail
//address using FILTER_SANITIZE_EMAIL
$field=filter_var($field, FILTER_SANITIZE_EMAIL);
//filter_var() validates the e-mail
//address using FILTER_VALIDATE_EMAIL
if(filter_var($field, FILTER_VALIDATE_EMAIL))
{
return TRUE;
}
else
{
return FALSE;
}
}
if (isset($_REQUEST['email']))
{//if "email" is filled out, proceed
//check if the email address is invalid
$mailcheck = spamcheck($_REQUEST['email']);
if ($mailcheck==FALSE)
{
echo "Invalid input";
}
else
{//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
}
else
{//if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text' /><br />
Subject: <input name='subject' type='text' /><br />
Message:<br />
<textarea name='message' rows='15' cols='40'>
</textarea><br />
<input type='submit' />
</form>";
}
?>
</body>
</html>
在上面的代码中，我们使用了 PHP 过滤器来对输入进行验证：
- FILTER_SANITIZE_EMAIL 从字符串中删除电子邮件的非法字符
- FILTER_VALIDATE_EMAIL 验证电子邮件地址
您可以在我们的 PHP 过滤器（http://www.php.cn/php/php-ref-filter.html）这一节中阅读更多有关过滤器的内容。