register-gpt.php

The following is a simple HTML registration form:

<form action="register.php" method="post">

<p>

<label for="firstname">First Name:</label>

<input type="text" name="firstname" id="firstname" />

</p>


<p>

<label for="lastname">Last Name:</label>

<input type="text" name="lastname" id="lastname" />

</p>


<p>

<label for="email">Email Address:</label>

<input type="text" name="email" id="email" />

</p>


<p>

<label for="password">Password:</label>

<input type="password" name="password" id="password" />

</p>


<p>

<label for="password_confirm">Confirm Password:</label>

<input type="password" name="password_confirm" id="password_confirm" />

</p>


<p>

<input type="submit" value="Register" />

</p>

</form>

The form is submitted to the register.php script, which is shown in Example 10-1.

Example 10-1. register.php: processing a form

<?php


// Connect to the database

$db = new mysqli('localhost', 'fred', 'shhh', 'bigsales');


// Check that the form has been submitted

if ($_SERVER['REQUEST_METHOD'] == 'POST') {


// Get the values from the form

$firstname = $_POST['firstname'];

$lastname = $_POST['lastname'];

$email = $_POST['email'];

$password = $_POST['password'];

$password_confirm = $_POST['password_confirm'];


// Check that the form has been submitted correctly

if (empty($firstname) || empty($lastname) ||

empty($email) || empty($password) ||

empty($password_confirm)) {

// If the form has been submitted incorrectly,

// redirect the user to the form

header('Location: register.php');

exit;

}


// Check that the user hasn't already registered

$query = "SELECT * FROM users WHERE email = '$email'";

$result = $db->query($query);

if ($result->num_rows > 0) {

// If the user has already registered,

// redirect the user to the home page

header('Location: index.php');

exit;

}


// Register the user

$query = "INSERT INTO users (firstname, lastname, email,

password, password_confirm) VALUES ('$firstname', '$lastname',

'$email', '$password', '$password_confirm')";

$result = $db->query($query);

if ($result->affected_rows > 0) {

// The user has been registered

echo '<p>You have been registered successfully.</p>';

} else {

// There was a problem registering the user

echo '<p>There was a problem registering you.</p>';

}

} else {

// If the form hasn't been submitted,

// display the form

echo '<form action="register.php" method="post">

<p>First Name: <input type="text" name="firstname" id="firstname" /></p>

<p>Last Name: <input type="text" name="lastname" id="lastname"