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In modern web development, user registration and login systems are fundamental features in most applications. This article walks through the process of using PHP to build simple and functional user registration and login APIs, making it easier for developers to implement authentication systems.
API, short for Application Programming Interface, defines how software components interact with each other. APIs are commonly used in web development to enable communication between frontend and backend systems. With well-designed APIs, developers can create modular and scalable application architectures.
Before implementing a registration system, you need to design a database to store user information. Here's a basic structure for a user table:
CREATE TABLE users (
id INT AUTO_INCREMENT PRIMARY KEY,
username VARCHAR(100) NOT NULL,
password VARCHAR(100) NOT NULL,
email VARCHAR(100) NOT NULL
);
This table includes fields for user ID, username, password, and email, which are sufficient for a basic user system.
The following is a PHP example for handling user registration:
<?php
// Connect to the database
$conn = mysqli_connect("localhost", "username", "password", "database_name");
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
$username = $_POST['username'];
$password = $_POST['password'];
$email = $_POST['email'];
// Check if the username already exists
$check_query = "SELECT * FROM users WHERE username = '$username' LIMIT 1";
$result = mysqli_query($conn, $check_query);
$user = mysqli_fetch_assoc($result);
if ($user) {
echo "Username already exists";
} else {
// Insert the new user into the database
$insert_query = "INSERT INTO users (username, password, email) VALUES ('$username', '$password', '$email')";
mysqli_query($conn, $insert_query);
echo "User registered successfully";
}
}
?>
This script receives the registration data via POST, checks if the username is already taken, and inserts a new user into the database if not.
Here’s a PHP example for processing user login:
<?php
// Connect to the database
$conn = mysqli_connect("localhost", "username", "password", "database_name");
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
$username = $_POST['username'];
$password = $_POST['password'];
// Validate user credentials
$check_query = "SELECT * FROM users WHERE username = '$username' AND password = '$password' LIMIT 1";
$result = mysqli_query($conn, $check_query);
$user = mysqli_fetch_assoc($result);
if ($user) {
echo "Login successful";
} else {
echo "Invalid username or password";
}
}
?>
This login script verifies the provided credentials against the database and responds accordingly, enabling basic user authentication.
This article explained how to create user registration and login APIs using PHP. With a properly designed database and PHP scripts, developers can quickly implement a working user authentication system. These foundations can later be enhanced with advanced features such as password encryption, token-based authentication, and input validation to improve security and scalability.
