CMU529: Advanced Web Development - Session 4

PHP Fundamentals & Server Setup

Full-stack Web Development with PHP and MySQL

James Williams

Birmingham Newman University

jwilliams@staff.newman.ac.uk

3-hour session

Learning Objectives

Understand PHP basics and server-side programming
Set up a local development environment with XAMPP
Learn PHP syntax, variables, and data types
Create basic PHP scripts and functions
Understand PHP's role in web development
Build simple dynamic web pages

What is PHP?

                    PHP (Hypertext Preprocessor) is a server-side scripting
                    language designed for web development
                

Open-source and free to use
Runs on web servers (Apache, Nginx)
Processes code on the server before sending to browser
Can generate dynamic HTML content
Integrates with databases (MySQL, PostgreSQL)
Widely used in web development

PHP Processing Flow

Request: Browser → Server

Process: Server → PHP Engine

Response: PHP → HTML → Browser

Watch:PHP Fundamentals Explained

See Moodle for supporting materials.

PHP vs Client-side Languages

PHP (Server-side):
✓ Runs on web server
✓ Processes before page loads
✓ Can access databases
✓ Secure (code not visible)
✓ Generates HTML dynamically
✓ Handles form processing
✓ Session management
✓ File operations
JavaScript (Client-side):
✓ Runs in browser
✓ Processes after page loads
✓ Cannot access databases directly
✗ Code visible to users
✓ Manipulates existing HTML
✓ Handles user interactions
✓ Local storage only
✓ Limited file access

Setting Up XAMPP

XAMPP Installation Steps:
1. Download XAMPP from apachefriends.org
2. Run installer (Windows/macOS/Linux)
3. Choose installation directory
4. Select components (Apache, MySQL, PHP)
5. Complete installation
6. Start XAMPP Control Panel
7. Start Apache and MySQL services
8. Access http://localhost/phpmyadmin
9. Create project folder in htdocs/

XAMPP provides Apache, MySQL, PHP, and phpMyAdmin
All-in-one package for local development
No complex configuration required
Perfect for learning and development

Basic PHP Syntax

<?php
// This is a PHP comment
echo "Hello, World!";
?>
<?php
/* Multi-line
comment */
$message = "Welcome to PHP";
echo $message;
?>
<?php
# Another comment style
$number = 42;
echo "The answer is: " . $number;
?>

PHP code is enclosed in <?php ?> tags
Statements end with semicolons
Variables start with $ symbol
Comments use //, /* */, or #

PHP Variables

Variable Declaration:
<?php
$name = "John";
$age = 25;
$price = 19.99;
$isActive = true;
$products = ["Apple", "Banana", "Orange"];
echo "Name: " . $name;
echo "Age: " . $age;
echo "Price: $" . $price;
echo "Active: " . ($isActive ? "Yes" : "No");
echo "Products: " . implode(", ", $products);
?>

Variables are dynamically typed
No need to declare data type
Case-sensitive names
Must start with letter or underscore

PHP Data Types

PHP Data Types:
// String
$name = "John Doe";
$message = 'Hello World';
// Integer
$age = 25;
$count = -10;
// Float
$price = 19.99;
$pi = 3.14159;
// Boolean
$isActive = true;
$isLoggedIn = false;
// Array
$colors = ["red", "green", "blue"];
$user = ["name" => "John", "age" => 25];
// Null
$empty = null;

PHP Arrays

Array Examples:
// Indexed Array
$products = ["Laptop", "Mouse", "Keyboard"];
echo $products[0]; // Outputs: Laptop
// Associative Array
$user = [
  "name" => "John",
  "email" => "john@example.com",
  "age" => 25
];
echo $user["name"]; // Outputs: John
// Multidimensional Array
$orders = [
  [
    "id" => 1,
    "product" => "Laptop",
    "price" => 999.99
  ],
  [
    "id" => 2,
    "product" => "Mouse",
    "price" => 29.99
  ]
];

PHP Functions

Function Examples:
// Basic function
function greet($name) {
  return "Hello, " . $name . "!";
}
// Function with default parameter
function calculateTotal($price, $tax = 0.20) {
  return $price * (1 + $tax);
}
// Function with multiple parameters
function createUser($name, $email, $age = 18) {
  return [
    "name" => $name,
    "email" => $email,
    "age" => $age
  ];
}
// Using functions
echo greet("John");
echo calculateTotal(100);
$user = createUser("Jane", "jane@example.com", 25);

PHP Control Structures

If Statement:
$age = 18;
if ($age >= 18) {
  echo "You are an adult";
} else {
  echo "You are a minor";
}
Switch Statement:
$status = "active";
switch ($status) {
  case "active":
    echo "User is active";
    break;
  case "inactive":
    echo "User is inactive";
    break;
  default:
    echo "Unknown status";
}

PHP Loops

Loop Examples:
// For loop
for ($i = 1; $i <= 5; $i++) {
      echo "Number: " . $i . "<br>";
    }
    // While loop
    $count = 0;
    while ($count < 3) {
          echo "Count: " . $count . "<br>";
          $count++;
        }
        // Foreach loop
        $products = ["Laptop", "Mouse", "Keyboard"];
        foreach ($products as $product) {
          echo "Product: " . $product . "<br>";
        }
        // Foreach with associative array
        $user = ["name" => "John", "age" => 25];
        foreach ($user as $key => $value) {
          echo $key . ": " . $value . "<br>";
        }

PHP and HTML Integration

<!DOCTYPE html>
<html>
<head>
  <title>PHP Example</title>
</head>
<body>
  <h1>Welcome to our Store</h1>
  <?php
  $products = ["Laptop", "Mouse", "Keyboard"];
  $currentTime = date("Y-m-d H:i:s");
  ?>
  <p>Current time: <?php echo $currentTime;
?></p>
  <h2>Our Products:</h2>
  <ul>
  <?php foreach ($products as $product): ?>
    <li><?php echo $product; ?></li>
  <?php endforeach; ?>
  </ul>
</body>
</html>

PHP Form Processing

HTML Form:
<form method="POST" action="process.php">
  <label for="name">Name:</label>
  <input type="text" name="name"
id="name"><br><br>
  <label for="email">Email:</label>
  <input type="email" name="email"
id="email"><br><br>
  <button type="submit">Submit</button>
</form>
PHP Processing (process.php):
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
  $name = $_POST["name"];
  $email = $_POST["email"];
  echo "Name: " . $name . "<br>";
  echo "Email: " . $email . "<br>";
}
?>

Task 1: Basic PHP Development

Instructions:

Set up XAMPP and start Apache service
Create a new project folder in htdocs directory
Create PHP files with the following:

Basic PHP syntax and variables
Arrays and loops
Functions with parameters
HTML integration
Simple form processing

Test all files through localhost
Create a simple product catalog page

Time: 45 minutes

This task will help you understand PHP basics and server setup

Break Time

15 Minutes

Take a break, ask questions, or catch up on the previous task.

Next: Secondary slides and Task 2

PHP Superglobals

Common Superglobals:
// $_POST - Form data
$name = $_POST["name"];
// $_GET - URL parameters
$id = $_GET["id"];
// $_SERVER - Server information
$method = $_SERVER["REQUEST_METHOD"];
$url = $_SERVER["REQUEST_URI"];
// $_SESSION - Session data
session_start();
$_SESSION["user_id"] = 123;
// $_COOKIE - Cookie data
$theme = $_COOKIE["theme"];
// $_FILES - File uploads
$uploadedFile = $_FILES["file"];

PHP Error Handling

Error Handling Examples:
// Display errors (development only)
ini_set('display_errors', 1);
error_reporting(E_ALL);
// Try-catch for exceptions
try {
  $result = 10 / 0;
} catch (Exception $e) {
  echo "Error: " . $e->getMessage();
}
// Custom error handling
function customErrorHandler($errno, $errstr) {
  echo "Error [$errno]: $errstr";
}
set_error_handler("customErrorHandler");
// Error logging
error_log("This is an error message", 0);

PHP Security Basics

Input Validation: Always validate user input
SQL Injection: Use prepared statements
XSS Prevention: Escape output with htmlspecialchars()
CSRF Protection: Use tokens for forms
File Upload Security: Validate file types and sizes

Security Examples:
// Input validation
$email = filter_var($_POST["email"], FILTER_VALIDATE_EMAIL);
// XSS prevention
$userInput = "<script>alert('XSS')</script>";
echo htmlspecialchars($userInput);
// File upload validation
$allowedTypes = ["jpg", "png", "gif"];
$fileExtension = strtolower(pathinfo($_FILES["file"]["name"],
PATHINFO_EXTENSION));
if (in_array($fileExtension, $allowedTypes)) {
  // Process file
}

PHP File Operations

File Operations Examples:
// Reading a file
$content = file_get_contents("data.txt");
echo $content;
// Writing to a file
$data = "Hello, World!";
file_put_contents("output.txt", $data);
// Reading file line by line
$handle = fopen("data.txt", "r");
while (($line = fgets($handle)) !== false) {
  echo $line;
}
fclose($handle);
// Checking if file exists
if (file_exists("config.php")) {
  include "config.php";
}

PHP Include and Require

Include Examples:
// Include file (continues if file not found)
include "header.php";
// Require file (stops if file not found)
require "config.php";
// Include once (prevents multiple inclusion)
include_once "functions.php";
// Require once (prevents multiple inclusion)
require_once "database.php";
// Example structure:
// header.php
<?php
echo "<h1>My Website</h1>";
?>
// footer.php
<?php
echo "<p>© 2024 My Website</p>";
?>

PHP Sessions

Session Management:
// Start session
session_start();
// Set session variables
$_SESSION["user_id"] = 123;
$_SESSION["username"] = "john_doe";
$_SESSION["logged_in"] = true;
// Access session variables
echo "User ID: " . $_SESSION["user_id"];
echo "Username: " . $_SESSION["username"];
// Check if user is logged in
if (isset($_SESSION["logged_in"]) && $_SESSION["logged_in"]) {
  echo "Welcome back!";
} else {
  echo "Please log in";
}
// Destroy session
session_destroy();

PHP Best Practices

Code Organization: Use meaningful file and folder names
Comments: Document your code properly
Naming Conventions: Use consistent naming (camelCase, snake_case)
Error Handling: Always handle errors gracefully
Security: Never trust user input
Performance: Optimize database queries and loops

Good Practices Example:
// Good: Clear variable names
$userFirstName = "John";
$userLastName = "Doe";
// Good: Proper error handling
if (!file_exists("config.php")) {
  die("Configuration file not found");
}
// Good: Input validation
$email = filter_var($_POST["email"], FILTER_VALIDATE_EMAIL);
if (!$email) {
  echo "Invalid email address";
}

Task 2: E-commerce PHP Foundation

Instructions:

Create a basic e-commerce PHP application with:

Product listing page with PHP arrays
Product detail page with URL parameters
Contact form with validation
Session-based shopping cart
Simple user authentication system

Implement proper error handling
Use include/require for code organization
Add security measures (input validation, XSS prevention)
Test all functionality thoroughly

Time: 45 minutes

This task will help you build a foundation for e-commerce PHP development

Session Summary

PHP is a powerful server-side scripting language
XAMPP provides a complete local development environment
PHP integrates seamlessly with HTML
Proper error handling and security are essential
Sessions enable user state management
Code organization and best practices improve maintainability

Next Session:

PHP Forms & Data Processing - Advanced form handling and validation