Login And Logout In PHP And MySQL using PHPMyAdmin

Login And Logout In PHP And MySQL using PHPMyAdmin

Here are some topics that could potentially be covered in a login and logout in PHP and MySQL using PHPMyAdmin article:

  1. Setting up a PHP and MySQL environment: This could include installing a local server (e.g., XAMPP or WAMP), creating a database and table in PHPMyAdmin, and configuring a PHP project to connect to the MySQL database.
  2. Designing a login form: This could include creating a HTML form for users to enter their login credentials (e.g., username and password), and using PHP to process and validate the form submission.
  3. Storing user credentials in the MySQL database: This could include creating a table to store user data, such as username, password, and other relevant information (e.g., email address, name).
  4. Implementing password hashing: This could include using PHP functions (e.g., password_hash() and password_verify()) to securely store and verify user passwords in the database.
  5. Creating a login system: This could include writing PHP code to query the database for a matching username and password, and using sessions to track logged-in users as they navigate through the site.
  6. Adding logout functionality: This could include creating a logout button or link that ends the user’s session and clears any session data.
  7. Implementing security measures: This could include adding additional measures to prevent unauthorized access, such as CAPTCHAs, two-factor authentication, and rate limiting.
  8. Debugging and troubleshooting: This could include common issues that might arise when developing a login system, such as incorrect database connections or incorrect password hashing, and how to resolve them.
  9. Advanced topics: This could include integrating third-party authentication methods (e.g., OAuth, SAML), implementing role-based access control, and adding password recovery functionality.

To create a login system using PHP and MySQL, you will need to perform the following steps:

  1. Create a database and table to store the user’s login information. For example, you might create a table called “users” with fields for the user’s ID, username, and password.
  2. Create an HTML form for the user to enter their login credentials (username and password). This form should include a submit button to send the login information to the server.
  3. Create a PHP script to handle the form submission. This script should first establish a connection to the MySQL database and then check the submitted username and password against the values stored in the “users” table.
  4. If the login information is correct, the script should set a session variable to indicate that the user is logged in and redirect them to a protected page. If the login information is incorrect, the script should display an error message and allow the user to try again.
  5. To log out, you can create a separate PHP script that destroys the session and redirects the user back to the login page.
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Here is an example of a PHP script that handles login and logout:

<?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>

And here is an example of a PHP script that handles logout:

<?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;
?>

This script starts the session and then unsets all session variables and destroys the session. Finally, it redirects the user back to the login page.

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It’s important to note that this is just an example and should not be used as-is in a production environment. It’s recommended to use a more secure method of storing and verifying passwords, such as using password hashing with a unique salt for each user.

Code For Creating Mysql Database And Table For This Script.

To create a MySQL database and table for the login system, you can use the following steps:

  1. Open the MySQL command line or use a tool like PHPMyAdmin to connect to your MySQL server.
  2. Create a new database by running the following command:



CREATE DATABASE login_system;

3.Use the newly created database by running the following command:

USE login_system;

4.Create a table to store the user’s login information by running the following command:

CREATE TABLE users (
    id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(30) NOT NULL,
    password VARCHAR(255) NOT NULL
);

This creates a table called “users” with fields for the user’s ID (which is set as the primary key and is automatically incremented), username, and password.

  1. Insert a test user into the table by running the following command:
INSERT INTO users (username, password) VALUES ('test', 'password');

This inserts a test user with the username “test” and the password “password”.

You can then use the PHP script provided in my previous response to handle login and logout, connecting to the “login_system” database and the “users” table to check the submitted username and password.

Code For welcome.php

This page starts the session and then checks if the user is logged in by checking the value of the “loggedin” session variable. If the user is not logged in, they are redirected to the login page.

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If the user is logged in, the page displays a welcome message with the user’s username and provides links to reset the password and log out of the account.

// 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>
    <div class="page-header">
        <h1>Hi, <b><?php echo htmlspecialchars($_SESSION["username"]); ?></b>. Welcome to our site.</h1>
    </div>
    <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>

Code For config.php

The “config.php” file is usually used to store database connection information and other global configuration settings for a PHP application. Here is an example of what a “config.php” file might look like for a login system that uses a MySQL database:

<?php
 
// Database credentials
define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'username');
define('DB_PASSWORD', 'password');
define('DB_NAME', 'login_system');
 
// Establish database connection
$link = mysqli_connect(DB_SERVER, DB_USERNAME, DB_PASSWORD, DB_NAME);
 
// Check connection
if($link === false){
    die("ERROR: Could not connect. " . mysqli_connect_error());
}
?>

In this example, the “DB_SERVER”, “DB_USERNAME”, “DB_PASSWORD”, and “DB_NAME” constants are defined with the values for the MySQL server, username, password, and database name, respectively. The script then uses these constants to establish a connection to the MySQL database using the mysqli_connect() function.

You will need to replace the placeholder values in this example with the actual values for your MySQL server and database. Make sure to keep the “config.php” file in a secure location, as it contains sensitive information that should not be publicly accessible.

You can then include the “config.php” file in any PHP script that needs to connect to the database by using the require_once statement:

require_once "config.php";

This will allow you to access the database connection using the $link variable. For example, you could use it to run a MySQL query like this:




$sql = "SELECT * FROM users WHERE username = 'test'";
$result = mysqli_query($link, $sql);

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