PHP MySQL 登录系统
在本教程中，你将学习如何使用 PHP 和 MySQL 构建登录系统。
实现用户认证机制
用户身份验证在现代 Web 应用程序中非常常见。它是一种安全机制，用于限制对站点上仅限成员的区域和工具的未授权访问。
在本教程中，我们将使用 PHP 和 MySQL 创建一个简单的注册和登录系统。本教程由两部分组成：第一部分我们将创建一个用户注册表单，第二部分我们将创建一个登录表单，以及一个欢迎页面和一个注销脚本。
建立注册系统
在本节中，我们将构建一个注册系统，允许用户通过填写Web 表单来创建新帐户。但是，首先我们需要创建一个包含所有用户数据的表。
第 1 步：创建数据库表
执行以下 SQL 查询以在 MySQL 数据库中创建 users 表。
CREATE TABLE users (
id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(50) NOT NULL UNIQUE,
password VARCHAR(255) NOT NULL,
created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);
有关在 MySQL 数据库系统中创建表的语法的详细信息，请查看 SQL CREATE TABLE 语句 教程。
第 2 步：创建配置文件
创建表后，我们需要创建一个 PHP 脚本才能连接到 MySQL 数据库服务器。让我们创建一个名为 config.php 的文件，并在其中放入以下代码。
面向过程式
<?php
/* Database credentials. Assuming you are running MySQL
server with default setting (user 'root' with no password) */
define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'root');
define('DB_PASSWORD', '');
define('DB_NAME', 'demo');
/* Attempt to connect to MySQL database */
$link = mysqli_connect(DB_SERVER, DB_USERNAME, DB_PASSWORD, DB_NAME);
// Check connection
if($link === false){
die("ERROR: Could not connect. " . mysqli_connect_error());
}
?>
面向对象式
<?php
/* Database credentials. Assuming you are running MySQL
server with default setting (user 'root' with no password) */
define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'root');
define('DB_PASSWORD', '');
define('DB_NAME', 'demo');
/* Attempt to connect to MySQL database */
$mysqli = new mysqli(DB_SERVER, DB_USERNAME, DB_PASSWORD, DB_NAME);
// Check connection
if($mysqli === false){
die("ERROR: Could not connect. " . $mysqli->connect_error);
}
?>
PDO 式
<?php
/* Database credentials. Assuming you are running MySQL
server with default setting (user 'root' with no password) */
define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'root');
define('DB_PASSWORD', '');
define('DB_NAME', 'demo');
/* Attempt to connect to MySQL database */
try{
$pdo = new PDO("mysql:host=" . DB_SERVER . ";dbname=" . DB_NAME, DB_USERNAME, DB_PASSWORD);
// Set the PDO error mode to exception
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e){
die("ERROR: Could not connect. " . $e->getMessage());
}
?>
注意： 在测试此代码之前，请根据 MySQL 服务器设置替换凭据，例如，将数据库名称’domo’替换为你自己的数据库名称，将 username root 替换为你自己的数据库用户名，如果有，请指定数据库密码。
第 3 步：创建注册表
让我们创建另一个 PHP 文件 register.php 并将以下示例代码放入其中。此示例代码将创建一个允许用户注册自己的 Web 表单。
如果用户尝试在不输入任何值的情况下提交表单，或者如果用户输入的用户名已被其他用户使用，则此脚本也会生成错误。
面向过程式
<?php
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$username = $password = $confirm_password = "";
$username_err = $password_err = $confirm_password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Validate username
if(empty(trim($_POST["username"]))){
$username_err = "Please enter a username.";
} else{
// Prepare a select statement
$sql = "SELECT id FROM users WHERE username = ?";
if($stmt = mysqli_prepare($link, $sql)){
// Bind variables to the prepared statement as parameters
mysqli_stmt_bind_param($stmt, "s", $param_username);
// Set parameters
$param_username = trim($_POST["username"]);
// Attempt to execute the prepared statement
if(mysqli_stmt_execute($stmt)){
/* store result */
mysqli_stmt_store_result($stmt);
if(mysqli_stmt_num_rows($stmt) == 1){
$username_err = "This username is already taken.";
} else{
$username = trim($_POST["username"]);
}
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
mysqli_stmt_close($stmt);
}
// Validate password
if(empty(trim($_POST["password"]))){
$password_err = "Please enter a password.";
} elseif(strlen(trim($_POST["password"])) < 6){
$password_err = "Password must have atleast 6 characters.";
} else{
$password = trim($_POST["password"]);
}
// Validate confirm password
if(empty(trim($_POST["confirm_password"]))){
$confirm_password_err = "Please confirm password.";
} else{
$confirm_password = trim($_POST["confirm_password"]);
if(empty($password_err) && ($password != $confirm_password)){
$confirm_password_err = "Password did not match.";
}
}
// Check input errors before inserting in database
if(empty($username_err) && empty($password_err) && empty($confirm_password_err)){
// Prepare an insert statement
$sql = "INSERT INTO users (username, password) VALUES (?, ?)";
if($stmt = mysqli_prepare($link, $sql)){
// Bind variables to the prepared statement as parameters
mysqli_stmt_bind_param($stmt, "ss", $param_username, $param_password);
// Set parameters
$param_username = $username;
$param_password = password_hash($password, PASSWORD_DEFAULT); // Creates a password hash
// Attempt to execute the prepared statement
if(mysqli_stmt_execute($stmt)){
// Redirect to login page
header("location: login.php");
} else{
echo "Something went wrong. Please try again later.";
}
}
// Close statement
mysqli_stmt_close($stmt);
}
// Close connection
mysqli_close($link);
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Sign Up</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<div class="wrapper">
<h2>Sign Up</h2>
<p>Please fill this form to create an account.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div class="form-group <?php echo (!empty($username_err)) ? 'has-error' : ''; ?>">
<label>Username</label>
<input type="text" name="username" class="form-control" value="<?php echo $username; ?>">
<span class="help-block"><?php echo $username_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($password_err)) ? 'has-error' : ''; ?>">
<label>Password</label>
<input type="password" name="password" class="form-control" value="<?php echo $password; ?>">
<span class="help-block"><?php echo $password_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($confirm_password_err)) ? 'has-error' : ''; ?>">
<label>Confirm Password</label>
<input type="password" name="confirm_password" class="form-control" value="<?php echo $confirm_password; ?>">
<span class="help-block"><?php echo $confirm_password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Submit">
<input type="reset" class="btn btn-default" value="Reset">
</div>
<p>Already have an account? <a href="login.php">Login here</a>.</p>
</form>
</div>
</body>
</html>
面向对象式
<?php
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$username = $password = $confirm_password = "";
$username_err = $password_err = $confirm_password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Validate username
if(empty(trim($_POST["username"]))){
$username_err = "Please enter a username.";
} else{
// Prepare a select statement
$sql = "SELECT id FROM users WHERE username = ?";
if($stmt = $mysqli->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bind_param("s", $param_username);
// Set parameters
$param_username = trim($_POST["username"]);
// Attempt to execute the prepared statement
if($stmt->execute()){
// store result
$stmt->store_result();
if($stmt->num_rows == 1){
$username_err = "This username is already taken.";
} else{
$username = trim($_POST["username"]);
}
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
$stmt->close();
}
// Validate password
if(empty(trim($_POST["password"]))){
$password_err = "Please enter a password.";
} elseif(strlen(trim($_POST["password"])) < 6){
$password_err = "Password must have atleast 6 characters.";
} else{
$password = trim($_POST["password"]);
}
// Validate confirm password
if(empty(trim($_POST["confirm_password"]))){
$confirm_password_err = "Please confirm password.";
} else{
$confirm_password = trim($_POST["confirm_password"]);
if(empty($password_err) && ($password != $confirm_password)){
$confirm_password_err = "Password did not match.";
}
}
// Check input errors before inserting in database
if(empty($username_err) && empty($password_err) && empty($confirm_password_err)){
// Prepare an insert statement
$sql = "INSERT INTO users (username, password) VALUES (?, ?)";
if($stmt = $mysqli->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bind_param("ss", $param_username, $param_password);
// Set parameters
$param_username = $username;
$param_password = password_hash($password, PASSWORD_DEFAULT); // Creates a password hash
// Attempt to execute the prepared statement
if($stmt->execute()){
// Redirect to login page
header("location: login.php");
} else{
echo "Something went wrong. Please try again later.";
}
}
// Close statement
$stmt->close();
}
// Close connection
$mysqli->close();
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Sign Up</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<div class="wrapper">
<h2>Sign Up</h2>
<p>Please fill this form to create an account.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div class="form-group <?php echo (!empty($username_err)) ? 'has-error' : ''; ?>">
<label>Username</label>
<input type="text" name="username" class="form-control" value="<?php echo $username; ?>">
<span class="help-block"><?php echo $username_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($password_err)) ? 'has-error' : ''; ?>">
<label>Password</label>
<input type="password" name="password" class="form-control" value="<?php echo $password; ?>">
<span class="help-block"><?php echo $password_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($confirm_password_err)) ? 'has-error' : ''; ?>">
<label>Confirm Password</label>
<input type="password" name="confirm_password" class="form-control" value="<?php echo $confirm_password; ?>">
<span class="help-block"><?php echo $confirm_password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Submit">
<input type="reset" class="btn btn-default" value="Reset">
</div>
<p>Already have an account? <a href="login.php">Login here</a>.</p>
</form>
</div>
</body>
</html>
PDO 式
<?php
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$username = $password = $confirm_password = "";
$username_err = $password_err = $confirm_password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Validate username
if(empty(trim($_POST["username"]))){
$username_err = "Please enter a username.";
} else{
// Prepare a select statement
$sql = "SELECT id FROM users WHERE username = :username";
if($stmt = $pdo->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bindParam(":username", $param_username, PDO::PARAM_STR);
// Set parameters
$param_username = trim($_POST["username"]);
// Attempt to execute the prepared statement
if($stmt->execute()){
if($stmt->rowCount() == 1){
$username_err = "This username is already taken.";
} else{
$username = trim($_POST["username"]);
}
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
unset($stmt);
}
// Validate password
if(empty(trim($_POST["password"]))){
$password_err = "Please enter a password.";
} elseif(strlen(trim($_POST["password"])) < 6){
$password_err = "Password must have atleast 6 characters.";
} else{
$password = trim($_POST["password"]);
}
// Validate confirm password
if(empty(trim($_POST["confirm_password"]))){
$confirm_password_err = "Please confirm password.";
} else{
$confirm_password = trim($_POST["confirm_password"]);
if(empty($password_err) && ($password != $confirm_password)){
$confirm_password_err = "Password did not match.";
}
}
// Check input errors before inserting in database
if(empty($username_err) && empty($password_err) && empty($confirm_password_err)){
// Prepare an insert statement
$sql = "INSERT INTO users (username, password) VALUES (:username, :password)";
if($stmt = $pdo->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bindParam(":username", $param_username, PDO::PARAM_STR);
$stmt->bindParam(":password", $param_password, PDO::PARAM_STR);
// Set parameters
$param_username = $username;
$param_password = password_hash($password, PASSWORD_DEFAULT); // Creates a password hash
// Attempt to execute the prepared statement
if($stmt->execute()){
// Redirect to login page
header("location: login.php");
} else{
echo "Something went wrong. Please try again later.";
}
}
// Close statement
unset($stmt);
}
// Close connection
unset($pdo);
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Sign Up</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<div class="wrapper">
<h2>Sign Up</h2>
<p>Please fill this form to create an account.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div class="form-group <?php echo (!empty($username_err)) ? 'has-error' : ''; ?>">
<label>Username</label>
<input type="text" name="username" class="form-control" value="<?php echo $username; ?>">
<span class="help-block"><?php echo $username_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($password_err)) ? 'has-error' : ''; ?>">
<label>Password</label>
<input type="password" name="password" class="form-control" value="<?php echo $password; ?>">
<span class="help-block"><?php echo $password_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($confirm_password_err)) ? 'has-error' : ''; ?>">
<label>Confirm Password</label>
<input type="password" name="confirm_password" class="form-control" value="<?php echo $confirm_password; ?>">
<span class="help-block"><?php echo $confirm_password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Submit">
<input type="reset" class="btn btn-default" value="Reset">
</div>
<p>Already have an account? <a href="login.php">Login here</a>.</p>
</form>
</div>
</body>
</html>
- 上面示例的输出（即注册表单）将如下所示：
在上面的示例中，我们使用 PHP password_hash() 函数从用户输入的密码字符串（第 75 行） 创建密码哈希。此函数使用强大的单向散列算法创建密码哈希。它还会在散列密码时自动生成并应用随机盐; 这意味着即使两个用户拥有相同的密码，他们的密码哈希值也会不同。
在登录时，我们将使用 PHP password_verify() 函数验证存储在数据库中的密码哈希的给定密码，如下一个示例所示。
我们使用 Bootstrap 框架快速而精美地制作表单布局。请查看 Bootstrap 教程 部分以了解有关此框架的更多信息。
提示： 加盐密码是一种广泛用于通过随机化密码哈希来保护密码的技术，因此如果两个用户具有相同的密码，则它们将不具有相同的密码哈希值。这是通过在散列之前将一个称为 salt 的随机字符串附加或预先添加到密码来完成的。
构建登录系统
在本节中，我们将创建一个登录表单，用户可以在其中输入用户名和密码。当用户提交表单时，将根据存储在数据库中的凭据验证这些输入，如果用户名和密码匹配，则授权用户访问该站点，否则将拒绝登录尝试。
第 1 步：创建登录表单
让我们创建一个名为 login.php 的文件，并在其中放置以下代码。
<?php
// Initialize the session
session_start();
// Check if the user is already logged in, if yes then redirect him to welcome page
if(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] === true){
header("location: welcome.php");
exit;
}
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$username = $password = "";
$username_err = $password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Check if username is empty
if(empty(trim($_POST["username"]))){
$username_err = "Please enter username.";
} else{
$username = trim($_POST["username"]);
}
// Check if password is empty
if(empty(trim($_POST["password"]))){
$password_err = "Please enter your password.";
} else{
$password = trim($_POST["password"]);
}
// Validate credentials
if(empty($username_err) && empty($password_err)){
// Prepare a select statement
$sql = "SELECT id, username, password FROM users WHERE username = ?";
if($stmt = mysqli_prepare($link, $sql)){
// Bind variables to the prepared statement as parameters
mysqli_stmt_bind_param($stmt, "s", $param_username);
// Set parameters
$param_username = $username;
// Attempt to execute the prepared statement
if(mysqli_stmt_execute($stmt)){
// Store result
mysqli_stmt_store_result($stmt);
// Check if username exists, if yes then verify password
if(mysqli_stmt_num_rows($stmt) == 1){
// Bind result variables
mysqli_stmt_bind_result($stmt, $id, $username, $hashed_password);
if(mysqli_stmt_fetch($stmt)){
if(password_verify($password, $hashed_password)){
// Password is correct, so start a new session
session_start();
// Store data in session variables
$_SESSION["loggedin"] = true;
$_SESSION["id"] = $id;
$_SESSION["username"] = $username;
// Redirect user to welcome page
header("location: welcome.php");
} else{
// Display an error message if password is not valid
$password_err = "The password you entered was not valid.";
}
}
} else{
// Display an error message if username doesn't exist
$username_err = "No account found with that username.";
}
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
mysqli_stmt_close($stmt);
}
// Close connection
mysqli_close($link);
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Login</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<div class="wrapper">
<h2>Login</h2>
<p>Please fill in your credentials to login.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div class="form-group <?php echo (!empty($username_err)) ? 'has-error' : ''; ?>">
<label>Username</label>
<input type="text" name="username" class="form-control" value="<?php echo $username; ?>">
<span class="help-block"><?php echo $username_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($password_err)) ? 'has-error' : ''; ?>">
<label>Password</label>
<input type="password" name="password" class="form-control">
<span class="help-block"><?php echo $password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Login">
</div>
<p>Don't have an account? <a href="register.php">Sign up now</a>.</p>
</form>
</div>
</body>
</html>
<?php
// Initialize the session
session_start();
// Check if the user is already logged in, if yes then redirect him to welcome page
if(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] === true){
header("location: welcome.php");
exit;
}
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$username = $password = "";
$username_err = $password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Check if username is empty
if(empty(trim($_POST["username"]))){
$username_err = "Please enter username.";
} else{
$username = trim($_POST["username"]);
}
// Check if password is empty
if(empty(trim($_POST["password"]))){
$password_err = "Please enter your password.";
} else{
$password = trim($_POST["password"]);
}
// Validate credentials
if(empty($username_err) && empty($password_err)){
// Prepare a select statement
$sql = "SELECT id, username, password FROM users WHERE username = ?";
if($stmt = $mysqli->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bind_param("s", $param_username);
// Set parameters
$param_username = $username;
// Attempt to execute the prepared statement
if($stmt->execute()){
// Store result
$stmt->store_result();
// Check if username exists, if yes then verify password
if($stmt->num_rows == 1){
// Bind result variables
$stmt->bind_result($id, $username, $hashed_password);
if($stmt->fetch()){
if(password_verify($password, $hashed_password)){
// Password is correct, so start a new session
session_start();
// Store data in session variables
$_SESSION["loggedin"] = true;
$_SESSION["id"] = $id;
$_SESSION["username"] = $username;
// Redirect user to welcome page
header("location: welcome.php");
} else{
// Display an error message if password is not valid
$password_err = "The password you entered was not valid.";
}
}
} else{
// Display an error message if username doesn't exist
$username_err = "No account found with that username.";
}
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
$stmt->close();
}
// Close connection
$mysqli->close();
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Login</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<h2>Login</h2>
<p>Please fill in your credentials to login.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div class="form-group <?php echo (!empty($username_err)) ? 'has-error' : ''; ?>">
<label>Username</label>
<input type="text" name="username" class="form-control" value="<?php echo $username; ?>">
<span class="help-block"><?php echo $username_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($password_err)) ? 'has-error' : ''; ?>">
<label>Password</label>
<input type="password" name="password" class="form-control">
<span class="help-block"><?php echo $password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Login">
</div>
<p>Don't have an account? <a href="register.php">Sign up now</a>.</p>
</form>
</div>
</body>
</html>
<?php
// Initialize the session
session_start();
// Check if the user is already logged in, if yes then redirect him to welcome page
if(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] === true){
header("location: welcome.php");
exit;
}
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$username = $password = "";
$username_err = $password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Check if username is empty
if(empty(trim($_POST["username"]))){
$username_err = "Please enter username.";
} else{
$username = trim($_POST["username"]);
}
// Check if password is empty
if(empty(trim($_POST["password"]))){
$password_err = "Please enter your password.";
} else{
$password = trim($_POST["password"]);
}
// Validate credentials
if(empty($username_err) && empty($password_err)){
// Prepare a select statement
$sql = "SELECT id, username, password FROM users WHERE username = :username";
if($stmt = $pdo->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bindParam(":username", $param_username, PDO::PARAM_STR);
// Set parameters
$param_username = trim($_POST["username"]);
// Attempt to execute the prepared statement
if($stmt->execute()){
// Check if username exists, if yes then verify password
if($stmt->rowCount() == 1){
if($row = $stmt->fetch()){
$id = $row["id"];
$username = $row["username"];
$hashed_password = $row["password"];
if(password_verify($password, $hashed_password)){
// Password is correct, so start a new session
session_start();
// Store data in session variables
$_SESSION["loggedin"] = true;
$_SESSION["id"] = $id;
$_SESSION["username"] = $username;
// Redirect user to welcome page
header("location: welcome.php");
} else{
// Display an error message if password is not valid
$password_err = "The password you entered was not valid.";
}
}
} else{
// Display an error message if username doesn't exist
$username_err = "No account found with that username.";
}
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
unset($stmt);
}
// Close connection
unset($pdo);
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Login</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<div class="wrapper">
<h2>Login</h2>
<p>Please fill in your credentials to login.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div class="form-group <?php echo (!empty($username_err)) ? 'has-error' : ''; ?>">
<label>Username</label>
<input type="text" name="username" class="form-control" value="<?php echo $username; ?>">
<span class="help-block"><?php echo $username_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($password_err)) ? 'has-error' : ''; ?>">
<label>Password</label>
<input type="password" name="password" class="form-control">
<span class="help-block"><?php echo $password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Login">
</div>
<p>Don't have an account? <a href="register.php">Sign up now</a>.</p>
</form>
</div>
</body>
</html>
- 上面示例的输出（即登录表单）将如下所示：
第 2 步：创建欢迎页面
这是我们的 welcome.php 文件的代码，用户在成功登录后被重定向。
<?php
// Initialize the session
session_start();
// Check if the user is logged in, if not then redirect him to login page
if(!isset($_SESSION["loggedin"]) || $_SESSION["loggedin"] !== true){
header("location: login.php");
exit;
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Welcome</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; text-align: center; }
</style>
</head>
<body>
<h1>Hi, <b><?php echo htmlspecialchars($_SESSION["username"]); ?></b>. Welcome to our site.</h1>
<p>
<a href="reset-password.php" class="btn btn-warning">Reset Your Password</a>
<a href="logout.php" class="btn btn-danger">Sign Out of Your Account</a>
</p>
</body>
</html>
如果数据来自外部来源（如匿名用户填写的表单），则可能会包含缩进的恶意脚本以启动跨站点脚本（XSS）攻击。因此，你必须使用 PHP htmlspecialchars() 函数转义此数据，然后才能在浏览器中显示它，以便它包含的任何 HTML 标记都变得无害。
例如，在转义特殊字符后，字符串 <script>alert("XSS")</script> 将变为 <script>alert("XSS")</script> 浏览器不执行该字符串。
第 3 步：创建注销脚本
现在，让我们创建一个 logout.php 文件。当用户单击注销或注销链接时，此文件中的脚本会破坏会话并将用户重定向回登录页面。
<?php
// Initialize the session
session_start();
// Unset all of the session variables
$_SESSION = array();
// Destroy the session.
session_destroy();
// Redirect to login page
header("location: login.php");
exit;
?>
添加密码重置功能
最后，在本节中，我们将向我们的登录系统添加密码重置实用程序。使用此功能登录的用户可以立即重置自己的帐户密码。
<?php
// Initialize the session
session_start();
// Check if the user is logged in, if not then redirect to login page
if(!isset($_SESSION["loggedin"]) || $_SESSION["loggedin"] !== true){
header("location: login.php");
exit;
}
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$new_password = $confirm_password = "";
$new_password_err = $confirm_password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Validate new password
if(empty(trim($_POST["new_password"]))){
$new_password_err = "Please enter the new password.";
} elseif(strlen(trim($_POST["new_password"])) < 6){
$new_password_err = "Password must have atleast 6 characters.";
} else{
$new_password = trim($_POST["new_password"]);
}
// Validate confirm password
if(empty(trim($_POST["confirm_password"]))){
$confirm_password_err = "Please confirm the password.";
} else{
$confirm_password = trim($_POST["confirm_password"]);
if(empty($new_password_err) && ($new_password != $confirm_password)){
$confirm_password_err = "Password did not match.";
}
}
// Check input errors before updating the database
if(empty($new_password_err) && empty($confirm_password_err)){
// Prepare an update statement
$sql = "UPDATE users SET password = ? WHERE id = ?";
if($stmt = mysqli_prepare($link, $sql)){
// Bind variables to the prepared statement as parameters
mysqli_stmt_bind_param($stmt, "si", $param_password, $param_id);
// Set parameters
$param_password = password_hash($new_password, PASSWORD_DEFAULT);
$param_id = $_SESSION["id"];
// Attempt to execute the prepared statement
if(mysqli_stmt_execute($stmt)){
// Password updated successfully. Destroy the session, and redirect to login page
session_destroy();
header("location: login.php");
exit();
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
mysqli_stmt_close($stmt);
}
// Close connection
mysqli_close($link);
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Reset Password</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<div class="wrapper">
<h2>Reset Password</h2>
<p>Please fill out this form to reset your password.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div class="form-group <?php echo (!empty($new_password_err)) ? 'has-error' : ''; ?>">
<label>New Password</label>
<input type="password" name="new_password" class="form-control" value="<?php echo $new_password; ?>">
<span class="help-block"><?php echo $new_password_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($confirm_password_err)) ? 'has-error' : ''; ?>">
<label>Confirm Password</label>
<input type="password" name="confirm_password" class="form-control">
<span class="help-block"><?php echo $confirm_password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Submit">
<a class="btn btn-link" href="welcome.php">Cancel</a>
</div>
</form>
</div>
</body>
</html>
<?php
// Initialize the session
session_start();
// Check if the user is logged in, if not then redirect to login page
if(!isset($_SESSION["loggedin"]) || $_SESSION["loggedin"] !== true){
header("location: login.php");
exit;
}
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$new_password = $confirm_password = "";
$new_password_err = $confirm_password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Validate new password
if(empty(trim($_POST["new_password"]))){
$new_password_err = "Please enter the new password.";
} elseif(strlen(trim($_POST["new_password"])) < 6){
$new_password_err = "Password must have atleast 6 characters.";
} else{
$new_password = trim($_POST["new_password"]);
}
// Validate confirm password
if(empty(trim($_POST["confirm_password"]))){
$confirm_password_err = "Please confirm the password.";
} else{
$confirm_password = trim($_POST["confirm_password"]);
if(empty($new_password_err) && ($new_password != $confirm_password)){
$confirm_password_err = "Password did not match.";
}
}
// Check input errors before updating the database
if(empty($new_password_err) && empty($confirm_password_err)){
// Prepare an update statement
$sql = "UPDATE users SET password = ? WHERE id = ?";
if($stmt = $mysqli->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bind_param("si", $param_password, $param_id);
// Set parameters
$param_password = password_hash($new_password, PASSWORD_DEFAULT);
$param_id = $_SESSION["id"];
// Attempt to execute the prepared statement
if($stmt->execute()){
// Password updated successfully. Destroy the session, and redirect to login page
session_destroy();
header("location: login.php");
exit();
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
$stmt->close();
}
// Close connection
$mysqli->close();
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Reset Password</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<div class="wrapper">
<h2>Reset Password</h2>
<p>Please fill out this form to reset your password.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div class="form-group <?php echo (!empty($new_password_err)) ? 'has-error' : ''; ?>">
<label>New Password</label>
<input type="password" name="new_password" class="form-control" value="<?php echo $new_password; ?>">
<span class="help-block"><?php echo $new_password_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($confirm_password_err)) ? 'has-error' : ''; ?>">
<label>Confirm Password</label>
<input type="password" name="confirm_password" class="form-control">
<span class="help-block"><?php echo $confirm_password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Submit">
<a class="btn btn-link" href="welcome.php">Cancel</a>
</div>
</form>
</div>
</body>
</html>
<?php
// Initialize the session
session_start();
// Check if the user is logged in, if not then redirect to login page
if(!isset($_SESSION["loggedin"]) || $_SESSION["loggedin"] !== true){
header("location: login.php");
exit;
}
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$new_password = $confirm_password = "";
$new_password_err = $confirm_password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Validate new password
if(empty(trim($_POST["new_password"]))){
$new_password_err = "Please enter the new password.";
} elseif(strlen(trim($_POST["new_password"])) < 6){
$new_password_err = "Password must have atleast 6 characters.";
} else{
$new_password = trim($_POST["new_password"]);
}
// Validate confirm password
if(empty(trim($_POST["confirm_password"]))){
$confirm_password_err = "Please confirm the password.";
} else{
$confirm_password = trim($_POST["confirm_password"]);
if(empty($new_password_err) && ($new_password != $confirm_password)){
$confirm_password_err = "Password did not match.";
}
}
// Check input errors before updating the database
if(empty($new_password_err) && empty($confirm_password_err)){
// Prepare an update statement
$sql = "UPDATE users SET password = :password WHERE id = :id";
if($stmt = $pdo->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bindParam(":password", $param_password, PDO::PARAM_STR);
$stmt->bindParam(":id", $param_id, PDO::PARAM_INT);
// Set parameters
$param_password = password_hash($new_password, PASSWORD_DEFAULT);
$param_id = $_SESSION["id"];
// Attempt to execute the prepared statement
if($stmt->execute()){
// Password updated successfully. Destroy the session, and redirect to login page
session_destroy();
header("location: login.php");
exit();
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
unset($stmt);
}
// Close connection
unset($pdo);
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Reset Password</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
<style type="text/css">
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<div class="wrapper">
<h2>Reset Password</h2>
<p>Please fill out this form to reset your password.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div class="form-group <?php echo (!empty($new_password_err)) ? 'has-error' : ''; ?>">
<label>New Password</label>
<input type="password" name="new_password" class="form-control" value="<?php echo $new_password; ?>">
<span class="help-block"><?php echo $new_password_err; ?></span>
</div>
<div class="form-group <?php echo (!empty($confirm_password_err)) ? 'has-error' : ''; ?>">
<label>Confirm Password</label>
<input type="password" name="confirm_password" class="form-control">
<span class="help-block"><?php echo $confirm_password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Submit">
<a class="btn btn-link" href="welcome.php">Cancel</a>
</div>
</form>
</div>
</body>
</html>