PHP 和 MySQL 登录查询
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PHP and MySQL login query
提问by Peter G
I am learning MySQL and PHP and am currently having trouble with this login process.
我正在学习 MySQL 和 PHP，目前在此登录过程中遇到问题。
It seems the MySQL query is not returning any rows and not redirecting me after a successful login.
似乎 MySQL 查询没有返回任何行，也没有在成功登录后重定向我。
PHP:
PHP：
$error_msg = "";
//checks the session to see if the user is logged in
if (!isset($_SESSION['userid'])) {
if (!isset($_POST['submit'])) {
$dbc = mysqli_connect('localhost', 'root', '', 'login')
or die('Error Connecting to Database on the SQL Server');
//grabs data from POST
$user_username = $_POST['username'];
$user_password = $_POST['password'];
//lookup username and password in the database
if (!empty($user_username) && !empty($password)) {
$query = "SELECT userid, username FROM tuser WHERE username = '$user_username' AND password = SHA('$user_password')";
$res = mysqli_query($dbc, $query);
//login is ok so set the user ID and username cookies, redirect to homepage
if (mysqli_num_rows($res) == 1) {
$row = mysqli_fetch_array($res);
$_SESSION['userid'] = $row['userid'];
$_SESSION['username'] = $row['username'];
setcookie('userid', $row['userid'], time() + (60 * 60 * 24 * 30), "/");
setcookie('username', $row['username'], time() + (60 * 60 * 24 * 30), "/");
setcookie('email', $row['email'], time() + (60 * 60 * 24 * 30), "/");
setcookie('password', $row['password'], time() + (60 * 60 * 24 * 30), "/");
//redirect after successful login
header("Location: index.php");
} else {
//the username and password are incorrect so set error message
$error_msg = 'Sorry, you must enter a valid username and password to log in. <a href="Signup.php">Please sign up!</a>';
}
}
}
}
HTML:
HTML：
<form action="login_process.php" method="post" class="login">
Username: <input type="text" name="username"/>
Password: <input type="password" name="password"/>
<input type="submit" value="submit"/>
</form>
Sorry for the sloppy code, I am familiar with PHP and MySQL and teaching myself how to do this. I made some changes and the code submits, but it does not redirect me, it just goes to login_process.php and does nothing. What am i missing? I appreciate all the help, thank you everyone!
抱歉，代码草率，我熟悉 PHP 和 MySQL 并自学如何执行此操作。我做了一些更改并提交了代码，但它没有重定向我，它只是转到 login_process.php 并且什么也不做。我错过了什么？我感谢所有的帮助，谢谢大家！
<?
session_start();
$error_msg = "";
//checks the session to see if the user is logged in
if (!isset($_SESSION['user_id']))
{
if (isset($_POST['submit']))
{
$user_username = mysql_real_escape_string($_POST['username']);
$user_password = mysql_real_escape_string($_POST['password']);
$dbc = mysqli_connect('localhost', 'root', '', 'login')
or die('Error Connecting to Database on the SQL Server');
//grabs data from POST
//lookup username and password in the database
if (!empty($user_username) && !empty($password))
{
$query = "SELECT userid, username FROM tuser WHERE username = '$user_username' AND password = SHA('$user_password')";
$res = mysqli_query($dbc, $query);
//login is ok so set the user ID and username cookies, redirect to homepage
if (mysqli_num_rows($res) == 1)
{
$row = mysqli_fetch_array($res);
$_SESSION['user_id'] = $row['userid'];
$_SESSION['user'] = $row['username'];
setcookie('userid', $row['userid'], time() + (60 * 60 * 24 * 30), "/");
setcookie('username', $row['username'], time() + (60 * 60 * 24 * 30), "/");
setcookie('email', $row['email'], time() + (60 * 60 * 24 * 30), "/");
setcookie('password', $row['password'], time() + (60 * 60 * 24 * 30), "/");
//redirect after successful login
header("Location: home.php");
echo mysqli_error($dbc);
}
else
{
//the username and password are incorrect so set error message
$error_msg = 'Sorry, you must enter a valid username and password to log in. <a href="Signup.php">Please sign up!</a>';
header("Location: home.php");
echo mysqli_error($dbc);
}
}
else
{
$error_msg = 'Please enter a username and password to log in. <a href="Signup.php">Please sign up!</a>';
header("Location: home.php");
echo mysqli_error($dbc);
}
}
}
?>
回答by Austin
I'm not sure if that's all all of your code but you must session_start()before you can access $_SESSION
我不确定这是否是您的全部代码，但您必须session_start()先访问，然后才能访问$_SESSION
Your code only queries unless a post isn't set so change it:
您的代码仅查询，除非未设置帖子，因此请更改它：
if (isset($_POST['submit'])) {
//your code
}
Also, be sure to escape user input to prevent sql injection:
另外，一定要转义用户输入以防止 sql 注入：
$user_username = mysql_real_escape_string($_POST['username']);
Make sure it's not a error in your SQL:
确保它不是您的 SQL 中的错误：
echo mysqli_error($dbc);
回答by Dave_Peachy
You are not executing anything the because of this line:
由于这一行，您没有执行任何操作：
if (!isset($_POST['submit'])) {
It should be change to
应该改成
if (isset($_POST['submit'])) {
isset() will return TRUE if that variable is set. !isset() will return TRUE if it is notset
如果设置了该变量，isset() 将返回 TRUE。如果未设置，!isset() 将返回 TRUE
回答by colonelclick
I see two problems:
我看到两个问题：
Your boolean is backwards on the line (i.e. remove the ! mark)
您的布尔值在线上向后（即删除！标记）
if (!isset($_POST['submit'])) {
The second problem is that your input button lacks a name="submit" attribute, so it is never being passed, so the variable will never be present regardless of the first problem.
第二个问题是你的输入按钮缺少 name="submit" 属性，所以它永远不会被传递，所以无论第一个问题如何，变量都不会出现。
回答by Peter G
Thank you everyone, got it working.
谢谢大家，搞定了。
<?
//Start session
session_start();
$_SESSION['message'] = "";
//Include database connection details
require_once('global.php');
//Connect to mysql server
$link = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD);
if(!$link) {
die('Failed to connect to server: ' . mysql_error());
}
//Select database
$db = mysql_select_db(DB_DATABASE);
if(!$db) {
die("Unable to select database");
}
if(!empty($login) && !empty($password)) {
$login = mysql_real_escape_string($_POST['login']);
$password = mysql_real_escape_string($_POST['password']);
$query = "SELECT * FROM tuser WHERE username = '$login' AND password = SHA('$password')";
$data = mysql_query($query);
if($data) {
if (mysql_num_rows($data) == 1 ) {
$row = mysql_fetch_assoc($data);
$_SESSION['userid'] = $row['userid'];
$_SESSION['username'] = $row['username'];
$_SESSION['message'] = "Welcome, " . $_SESSION['username'];
header('Location: member.php');
exit();
}
else {
$_SESSION['message'] = "Please enter a valid username or password";
header('Location: error.php');
exit();
}
}
else {
die("Query failed");
}
}
else {
$_SESSION['message'] = "Please enter a username or password";
header('Location: error.php');
exit();
}
?>
