PHP MySQL 登入系統
在本教程中，你將學習如何使用 PHP 和 MySQL 構建登入系統。
實現使用者認證機制
使用者身份驗證在現代 Web 應用程式中非常常見。它是一種安全機制，用於限制對站點上僅限成員的區域和工具的未授權訪問。
在本教程中，我們將使用 PHP 和 MySQL 建立一個簡單的註冊和登入系統。本教程由兩部分組成：第一部分我們將建立一個使用者登錄檔單，第二部分我們將建立一個登入表單，以及一個歡迎頁面和一個登出指令碼。
建立註冊系統
在本節中，我們將構建一個註冊系統，允許使用者通過填寫Web 表單來建立新帳戶。但是，首先我們需要建立一個包含所有使用者資料的表。
第 1 步：建立資料庫表
執行以下 SQL 查詢以在 MySQL 資料庫中建立 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
);
有關在 MySQL 資料庫系統中建立表的語法的詳細資訊，請檢視 SQL CREATE TABLE 語句 教程。
第 2 步：建立配置檔案
建立表後，我們需要建立一個 PHP 指令碼才能連線到 MySQL 資料庫伺服器。讓我們建立一個名為 config.php 的檔案，並在其中放入以下程式碼。
程序導向式
<?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());
}
?>
物件導向式
<?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： 在測試此程式碼之前，請根據 MySQL 伺服器設定替換憑據，例如，將資料庫名稱’domo’替換為你自己的資料庫名稱，將 username root 替換為你自己的資料庫使用者名稱，如果有，請指定資料庫密碼。
第 3 步：建立登錄檔
讓我們建立另一個 PHP 檔案 register.php 並將以下示例程式碼放入其中。此示例程式碼將建立一個允許使用者註冊自己的 Web 表單。
如果使用者嘗試在不輸入任何值的情況下提交表單，或者如果使用者輸入的使用者名稱已被其他使用者使用，則此指令碼也會生成錯誤。
程序導向式
<?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>
物件導向式
<?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 $confirm_password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Submit">
<input type="reset" class="btn btn-default" value="Reset">
</div>
<p>Already have an account? <a href="login.php">Login here</a>.</p>
</form>
</div>
</body>
</html>
- 上面示例的輸出（即登錄檔單）將如下所示：
在上面的示例中，我們使用 PHP password_hash() 函式從使用者輸入的密碼字串（第 75 行） 建立密碼雜湊。此函式使用強大的單向雜湊演算法建立密碼雜湊。它還會在雜湊密碼時自動生成並應用隨機鹽; 這意味著即使兩個使用者擁有相同的密碼，他們的密碼雜湊值也會不同。
在登入時，我們將使用 PHP password_verify() 函式驗證儲存在資料庫中的密碼雜湊的給定密碼，如下一個示例所示。
我們使用 Bootstrap 框架快速而精美地製作表單佈局。請檢視 Bootstrap 教程 部分以瞭解有關此框架的更多資訊。
提示： 加鹽密碼是一種廣泛用於通過隨機化密碼雜湊來保護密碼的技術，因此如果兩個使用者具有相同的密碼，則它們將不具有相同的密碼雜湊值。這是通過在雜湊之前將一個稱為 salt 的隨機字串附加或預先新增到密碼來完成的。
構建登入系統
在本節中，我們將建立一個登入表單，使用者可以在其中輸入使用者名稱和密碼。當使用者提交表單時，將根據儲存在資料庫中的憑據驗證這些輸入，如果使用者名稱和密碼匹配，則授權使用者訪問該站點，否則將拒絕登入嘗試。
第 1 步：建立登入表單
讓我們建立一個名為 login.php 的檔案，並在其中放置以下程式碼。
<?php
// Initialize the session
session_start();
// Check if the user is already logged in, if yes then redirect him to welcome page
if(isset($_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 $password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Login">
</div>
<p>Don't have an account? <a href="register.php">Sign up now</a>.</p>
</form>
</div>
</body>
</html>
- 上面示例的輸出（即登入表單）將如下所示：
第 2 步：建立歡迎頁面
這是我們的 welcome.php 檔案的程式碼，使用者在成功登入後被重定向。
<?php
// Initialize the session
session_start();
// Check if the user is logged in, if not then redirect him to login page
if(!isset($_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>
如果資料來自外部來源（如匿名使用者填寫的表單），則可能會包含縮排的惡意指令碼以啟動跨站點指令碼（XSS）攻擊。因此，你必須使用 PHP htmlspecialchars() 函式轉義此資料，然後才能在瀏覽器中顯示它，以便它包含的任何 HTML 標記都變得無害。
例如，在轉義特殊字元後，字串 <script>alert("XSS")</script> 將變為 <script>alert("XSS")</script> 瀏覽器不執行該字串。
第 3 步：建立登出指令碼
現在，讓我們建立一個 logout.php 檔案。當使用者單擊登出或登出連結時，此檔案中的指令碼會破壞會話並將使用者重定向回登入頁面。
<?php
// Initialize the session
session_start();
// Unset all of the session variables
$_SESSION = array();
// Destroy the session.
session_destroy();
// Redirect to login page
header("location: login.php");
exit;
?>
新增密碼重置功能
最後，在本節中，我們將向我們的登入系統新增密碼重置實用程式。使用此功能登入的使用者可以立即重置自己的帳戶密碼。
<?php
// Initialize the session
session_start();
// Check if the user is logged in, if not then redirect to login page
if(!isset($_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>