我有一个数据库设置，我正在创建一个用户必须使用他们的用户名，电子邮件和密码注册的网站。但是，出于某种原因，每当我点击寄存器而不输入任何信息时，它仍然会注册到数据库而不显示错误。这是代码。
<?php
// First we execute our common code to connection to the database and start the session
require("common.php");
// 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($_POST))
{
// Ensure that the user has entered a non-empty username
if(empty($_POST['username']))
{
// 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.
$username_error = "Please enter a username";
}
// Ensure that the user has entered a non-empty password
if(empty($_POST['password']))
{
$password_error = "Please enter a password";
}
// Make sure the user entered a valid E-Mail address
// filter_var is a useful PHP function for validating form input, see:
// http://us.php.net/manual/en/function.filter-var.php
// http://us.php.net/manual/en/filter.filters.php
if(!filter_var($_POST['email'], FILTER_VALIDATE_EMAIL))
{
$invalid_email = "Invalid email";
}
// We will use this SQL query to see whether the username entered by the
// user is already in use. A SELECT query is used to retrieve data from the database.
// :username is a special token, we will substitute a real value in its place when
// we execute the query.
$query = "
SELECT
1
FROM users
WHERE
username = :username
";
// This contains the definitions for any special tokens that we place in
// our SQL query. In this case, we are defining a value for the token
// :username. It is possible to insert $_POST['username'] directly into
// your $query string; however doing so is very insecure and opens your
// code up to SQL injection exploits. Using tokens prevents this.
// For more information on SQL injections, see Wikipedia:
// http://en.wikipedia.org/wiki/SQL_Injection
$query_params = array(
':username' => $_POST['username']
);
try
{
// These two statements run the query against your database table.
$stmt = $db->prepare($query);
$result = $stmt->execute($query_params);
}
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());
}
// The fetch() method returns an array representing the "next" row from
// the selected results, or false if there are no more rows to fetch.
$row = $stmt->fetch();
// If a row was returned, then we know a matching username was found in
// the database already and we should not allow the user to continue.
if($row)
{
$username_exist = "This username already exists!";
}
// Now we perform the same type of check for the email address, in order
// to ensure that it is unique.
$query = "
SELECT
1
FROM users
WHERE
email = :email
";
$query_params = array(
':email' => $_POST['email']
);
try
{
$stmt = $db->prepare($query);
$result = $stmt->execute($query_params);
}
catch(PDOException $ex)
{
die("Failed to run query: " . $ex->getMessage());
}
$row = $stmt->fetch();
if($row)
{
$email_registered = "This email is already registered!";
}
// 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 = "
INSERT INTO users (
username,
password,
salt,
email
) VALUES (
:username,
:password,
:salt,
:email
)
";
// 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.
// For more information:
// http://en.wikipedia.org/wiki/Salt_%28cryptography%29
// http://en.wikipedia.org/wiki/Brute-force_attack
// http://en.wikipedia.org/wiki/Rainbow_table
$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. For more information:
// http://en.wikipedia.org/wiki/Cryptographic_hash_function
$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);
}
// Here we prepare our tokens for insertion into the SQL query. We do not
// store the original password; only the hashed version of it. We do store
// the salt (in its plaintext form; this is not a security risk).
$query_params = array(
':username' => $_POST['username'],
':password' => $password,
':salt' => $salt,
':email' => $_POST['email']
);
try
{
// Execute the query to create the user
$stmt = $db->prepare($query);
$result = $stmt->execute($query_params);
}
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: login.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 login.php");
}
?>
这是我的PHP代码。下面是我的HTML代码。请告诉我我的错误，所以我可以确保改变它。
现在，由于Stackoverflow中不支持所有HTMl标记存在问题，我已将其发布在pastebin中。
答案 0 :(得分：1)
问题是，当错误发生时你不要退出程序，以便它继续运行并执行查询。
您可以尝试添加一个额外的变量来确定是否存在错误并且您只是跳过了mysql查询。
$isError = false;
if(empty($username))
{
$isError = true;
}
if($isError)
{
// Handle error
}else{
// Execute query
}
或者将所有if语句放入php函数并在发生错误时抛出异常并使用try {} catch（）语句处理它。
function TestSomething($username)
{
if(empty($username))
throw new Exception("No username");
}
try
{
TestSomething("");
// Execute query
}catch(Exception $ex)
{
// Handle error
echo $ex->getMessage(); // Prints no username
}
但你可以放一个＆＃34;抛出新的例外（＆＃34; Message＆＃34;）＆＃34;进入你的try语句，它将停止执行程序并跳转到catch语句。
答案 1 :(得分：0)
它仍在注册您的信息，因为如果遇到错误，您永远不会停止执行。如何执行此操作可能会有所不同，具体取决于您是否只想向用户显示单个错误消息或所有错误消息，但可能的简单解决方案可能如下所示：
$error = false;
if(empty($_POST['username'])) {
$error = "Please enter a username";
}
if(empty($_POST['password'])) {
$error = "Please enter a password";
}
// .. further validation ..
if(!$error) {
// Insert new user
} else {
// Redirect back to form with error message(s) set
}