我有以下代码来更新我的数据库（更改密码）。我知道我使用的方法有点老派，但该网站仅用作测试。我已经从另一个网站复制了代码，并且之前使用它来执行插入查询（不是更新）。
由于某种原因，数据库没有更新，我收到以下错误消息：
数组警告：无法修改标头信息 - 标头已由 /home/content/47/11368447/html/CCC/changepassword 中的（输出开始于 /home/content/47/11368447/html/CCC/changepassword.php:64）发送第 75 行的 .php 重定向到 stafflist.php
我是 php 新手，感谢我能得到的所有帮助。
这是代码：
// First we execute our common code to connection to the database and start the session
require("common.php");
$id = $_GET['id'];
// This if statement checks to determine whether the registration form has been submitted
// If it has, then the registration code is run, otherwise the form is displayed
if(!empty($_POST))
{
// Ensure that the user has entered a non-empty password
if(empty($_POST['password']))
{
die("Please enter a password.");
}
// Ensure that the user has entered a non-empty username
if(empty($_POST['confirmpassword']))
{
// Note that die() is generally a terrible way of handling user errors
// like this. It is much better to display the error with the form
// and allow the user to correct their mistake. However, that is an
// exercise for you to implement yourself.
die("Please confirm your password.");
}
if ($_POST['password'] == $_POST['confirmpassword']) {
// An INSERT query is used to add new rows to a database table.
// Again, we are using special tokens (technically called parameters) to
// protect against SQL injection attacks.
$query = "UPDATE Staff SET password=:password, salt=:salt WHERE id=:id";
// A salt is randomly generated here to protect again brute force attacks
// and rainbow table attacks. The following statement generates a hex
// representation of an 8 byte salt. Representing this in hex provides
// no additional security, but makes it easier for humans to read.
$salt = dechex(mt_rand(0, 2147483647)) . dechex(mt_rand(0, 2147483647));
// This hashes the password with the salt so that it can be stored securely
// in your database. The output of this next statement is a 64 byte hex
// string representing the 32 byte sha256 hash of the password. The original
// password cannot be recovered from the hash.
$password = hash('sha256', $_POST['password'] . $salt);
// Next we hash the hash value 65536 more times. The purpose of this is to
// protect against brute force attacks. Now an attacker must compute the hash 65537
// times for each guess they make against a password, whereas if the password
// were hashed only once the attacker would have been able to make 65537 different
// guesses in the same amount of time instead of only one.
for($round = 0; $round < 65536; $round++)
{
$password = hash('sha256', $password . $salt);
}
try
{
// Execute the query to create the user
$stmt = $db->prepare($query);
$stmt->execute(array(
':password' => $password,
':salt' => $salt,
':id' => $id));
echo $db->errorInfo();
}
catch(PDOException $ex)
{
// Note: On a production website, you should not output $ex->getMessage().
// It may provide an attacker with helpful information about your code.
die("Failed to run query: " . $ex->getMessage());
}
// This redirects the user back to the login page after they register
header("Location: stafflist.php");
// Calling die or exit after performing a redirect using the header function
// is critical. The rest of your PHP script will continue to execute and
// will be sent to the user if you do not die or exit.
die("Redirecting to stafflist.php");
}
die("Passwords do not match.");
}
谢谢，乔