Struggling with Image Display and Undefined Variables in PHP Script

This content originally appeared on DEV Community and was authored by Misbah bagaskara purwanto

Hey, dev.to community,

I’m working on a PHP-based online shop and encountering a couple of issues in my onlineshop.php script. I could use some guidance on how to resolve these problems. Here’s a summary of the issues I’m facing:

Context:

File Path: /var/www/html/online_shop/public/onlineshop/onlineshop.php
Issue: Images aren’t displaying correctly, and I’m receiving PHP warnings about undefined variables.

Code Snippet:

<?php
session_start();
include_once 'db_connect.php';

// Enable error reporting
error_reporting(E_ALL);
ini_set('display_errors', 1);

// Handle logout if logout parameter is set
if (isset($_GET['logout']) && $_GET['logout'] == 'true') {
    $_SESSION = array();
    session_destroy();
    header("Location: onlineshop.php");
    exit();
}

// Check if the user is logged in
if (isset($_SESSION['user_id'])) {
    $navbar_links = '
        <li class="nav-item">
            <a class="nav-link" href="profile.php">Profile</a>
        </li>
        <li class="nav-item">
            <a class="nav-link" href="onlineshop.php?logout=true">Logout</a>
        </li>
    ';
} else {
    $navbar_links = '
        <li class="nav-item">
            <a class="nav-link" href="login.php">Login</a>
        </li>
        <li class="nav-item">
            <a class="nav-link" href="register.php">Register</a>
        </li>
    ';
}

// Fetch products from database
$sql_fetch_products = "SELECT * FROM products";
$result = $conn->query($sql_fetch_products);

if (!isset($_SESSION['user_id'])) {
    header("Location: login.php");
    exit();
}

$user_id = $_SESSION['user_id'];

// Fetch username based on user_id
$sql = $conn->prepare("SELECT username FROM users WHERE id = ?");
$sql->bind_param('i', $user_id);
$sql->execute();
$sql->bind_result($username);
$sql->fetch();
$sql->close();

// Fetch chat messages
$chat_query = "SELECT * FROM chat_messages WHERE sender='$username' OR receiver='$username' ORDER BY timestamp DESC";
$chat_result = $conn->query($chat_query);

// Handle sending chat messages
if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['chat_message'])) {
    $receiver = 'admin'; // Static value for admin
    $message = $_POST['chat_message'];
    $sender = $username;

    $stmt = $conn->prepare("INSERT INTO chat_messages (sender, receiver, message) VALUES (?, ?, ?)");
    $stmt->bind_param("sss", $sender, $receiver, $message);
    $stmt->execute();
    $stmt->close();
    header("Location: onlineshop.php");
    exit;
}
?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Online Shop</title>
    <link href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" rel="stylesheet">
    <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
</head>
<body>
    <!-- Navbar -->
    <nav class="navbar navbar-expand-lg navbar-light bg-light">
        <a class="navbar-brand" href="#">Indonesian Product</a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>
        <div class="collapse navbar-collapse" id="navbarNav">
            <ul class="navbar-nav ml-auto">
                <li class="nav-item">
                    <a class="nav-link" href="onlineshop.php">Home</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="about.php">About</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="contact.php">Contact</a>
                </li>
                <?php echo $navbar_links; ?>
            </ul>
        </div>
    </nav>

    <div class="container">
        <div class="marquee">
            <marquee behavior="scroll" direction="left">Welcome to our Online Shop!</marquee>
        </div>
    </div>

    <div class="container">
        <h1 class="mt-4 mb-4">Products</h1>
        <div class="card-columns">
            <?php
            if ($result && $result->num_rows > 0) {
                while ($row = $result->fetch_assoc()) {
                    echo '<div class="card">';
                    echo '<a href="product_detail.php?product_id=' . $row['id'] . '">';

                    // Image path
                    $imagePath = '/online_shop/public/' . $row['image'];
                    echo 'Image Path: ' . $imagePath . '<br>';

                    // Verify if the file exists
                    if (file_exists('/var/www/html' . $imagePath)) {
                        echo 'File exists<br>';
                    } else {
                        echo 'File does not exist<br>';
                    }

                    // Display the image
                    echo '<img src="' . $imagePath . '" class="card-img-top" alt="Product Image">';
                    echo '<div class="card-body">';
                    echo '<h5 class="card-title">' . $row['name'] . '</h5>';
                    echo '<p class="card-text">' . $row['description'] . '</p>';
                    echo '<p class="card-text">Price: ' . $row['price'] . '</p>';
                    echo '</div>';
                    echo '</a>';
                    echo '</div>';
                }
            } else {
                echo '<p>No products found.</p>';
            }
            ?>
        </div>
    </div>

   <!-- Chat Section -->
   <div class="card">
        <div class="card-header">Chat with Admin</div>
        <div class="card-body">
            <div class="chat-box" style="height: 300px; overflow-y: scroll;">
                <?php while ($chat = $chat_result->fetch_assoc()) { ?>
                    <div>
                        <strong><?php echo htmlspecialchars($chat['sender']); ?>:</strong>
                        <span><?php echo htmlspecialchars($chat['message']); ?></span>
                        <small class="text-muted"><?php echo $chat['timestamp']; ?></small>
                    </div>
                <?php } ?>
            </div>
            <form action="onlineshop.php" method="POST">
                <div class="form-group">
                    <label for="chat_message">Message</label>
                    <textarea class="form-control" id="chat_message" name="chat_message" required></textarea>
                </div>
                <button type="submit" class="btn btn-primary">Send</button>
            </form>
        </div>
    </div>

    <script>
        $(document).ready(function() {
            function checkNewMessages() {
                $.ajax({
                    url: 'check_new_messages.php',
                    method: 'GET',
                    success: function(data) {
                        if (data.new_messages > 0) {
                            $('#chat-notification-count').text(data.new_messages);
                        } else {
                            $('#chat-notification-count').text('');
                        }
                    }
                });
            }

            // Check for new messages every 5 seconds
            setInterval(checkNewMessages, 5000);
        });
    </script>

    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.bundle.min.js"></script>
</body>
</html>

Issues:

Image Path Problem: The image path generated for displaying product images is incorrect. The URL is showing as /photo_product/photo_product/Screenshot%202024-07-01%20080501.png, which leads to a 404 Not Found error.
PHP Warnings: I’m seeing warnings related to undefined variables and array offsets.

Questions:

Image Path: How can I correct the image path to ensure that images are displayed properly?
PHP Warnings: What steps can I take to resolve the warnings related to undefined variables and array offsets?
Debugging Advice: Any suggestions on effective debugging techniques for these issues?

Any help or insights would be greatly appreciated. Thanks in advance!

This content originally appeared on DEV Community and was authored by Misbah bagaskara purwanto

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Misbah bagaskara purwanto | Sciencx (2024-07-27T03:44:20+00:00) Struggling with Image Display and Undefined Variables in PHP Script — Need Help!. Retrieved from https://www.scien.cx/2024/07/27/struggling-with-image-display-and-undefined-variables-in-php-script-need-help/

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" » Struggling with Image Display and Undefined Variables in PHP Script — Need Help!." Misbah bagaskara purwanto | Sciencx - Saturday July 27, 2024, https://www.scien.cx/2024/07/27/struggling-with-image-display-and-undefined-variables-in-php-script-need-help/

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