PHP Crash Course: The Complete, Modern, Hands-On Guide

Cover....1

Title Page....4

Copyright....5

Dedication....6

About the Author....8

About the Technical Reviewers....8

Brief Contents....10

Contents in Detail....12

Acknowledgments....24

Introduction....26

Who This Book Is For....27

Why PHP?....27

What You Will Learn....27

Online Resources....30

Part I: Language Fundamentals....32

1. PHP Program Basics....34

Two Methods to Run PHP....34

The Replit Online Coding Environment....35

A Local PHP Installation....39

Template Text vs. PHP Code....44

Comments....46

Variables....47

Creating Variables....48

Using Variables....49

Naming Variables....49

Constants....51

Operators and Operands....52

Arithmetic Operators....52

Combined Arithmetic Assignment Operators....53

Increment and Decrement Operators....54

Summary....55

Exercises....55

2. Data Types....58

PHP Data Types....59

Scalar Data Types....59

The Special NULL Type....61

Functions to Test for a Data Type....62

Type Juggling....63

Numeric Contexts....64

String Contexts....66

Comparative Contexts....66

Logical and Other Contexts....70

Type Casting....70

Summary....71

Exercises....71

3. Strings and String Functions....72

Whitespace....73

Single-Quoted Strings....74

Joining Strings: Concatenation....75

Double-Quoted Strings....77

Handling the Character After a Variable Name....78

Incorporating Unicode Characters....79

Heredocs....80

Escape Sequences....81

Indention....81

Nowdocs....83

Built-in String Functions....84

Converting to Upper- and Lowercase....84

Searching and Counting....85

Extracting and Replacing Substrings....87

Trimming Whitespace....90

Removing All Unnecessary Whitespace....91

Repeating and Padding....92

Summary....93

Exercises....93

4. Conditionals....96

Conditions Are True or False....97

if Statements....97

if...else Statements....98

Nested if...else Statements....99

if...elseif...else Statements....99

Alternative Syntax....100

Logical Operators....101

NOT....101

AND....102

OR....103

XOR....104

switch Statements....104

match Statements....106

The Ternary Operator....107

The Null-Coalescing Operator....108

Summary....109

Exercises....110

5. Custom Functions....112

Separating Code into Multiple Files....113

Reading in and Executing Another Script....113

Creating Absolute Filepaths....114

Declaring and Calling a Function....115

Parameters vs. Arguments....117

Errors from Incorrect Function Calls....118

Type Juggling....120

Functions Without Explicit Return Values....121

Returning NULL....122

Exiting a Function Early....123

Calling Functions from Within Functions....124

Functions with Multiple Return and Parameter Types....126

Nullable Types....126

Union Types....129

Optional Parameters....131

Positional vs. Named Arguments....133

Skipped Parameters....135

Pass-by-Value vs. Pass-by-Reference....136

Summary....138

Exercises....139

Part II: Working with Data....140

6. Loops....142

while Loops....143

do... while Loops....144

Boolean Flags....145

break Statements....147

for Loops....148

Using the Counter in the Loop....149

Skipping Loop Statements....150

Handling the Last Iteration Differently....151

Alternative Loop Syntax....153

Avoiding Infinite Loops....154

Summary....155

Exercises....155

7. Simple Arrays....156

Creating an Array and Accessing Its Values....157

Updating an Array....158

Appending an Element....158

Adding an Element with a Specific Key....159

Appending Multiple Elements....160

Removing the Last Element....161

Retrieving Information About an Array....162

Looping Through an Array....164

Using a foreach Loop....165

Accessing Keys and Values....165

Imploding an Array....166

Functions with a Variable Number of Arguments....167

Array Copies vs. Array References....168

Treating Strings as Arrays of Characters....170

Other Array Functions....172

Summary....172

Exercises....172

8. Sophisticated Arrays....174

Declaring Array Keys Explicitly....175

Arrays with Strings as Keys....177

Multidimensional Arrays....178

More Array Operations....180

Removing Any Element from an Array....180

Combining and Comparing Arrays....181

Destructuring an Array into Multiple Variables....183

Callback Functions and Arrays....184

Summary....186

Exercises....186

9. Files and Directories....188

Reading a File into a String....189

Confirming That a File Exists....190

Touching a File....192

Ensuring That a Directory Exists....192

Writing a String to a Text File....194

Managing Files and Directories....195

Reading a File into an Array....197

Using Lower-Level File Functions....197

Processing Multiple Files....199

JSON and Other File Types....202

Summary....204

Exercises....204

Part III: Programming Web Applications....206

10. ClientServer Communication and Web Development Basics....208

The HTTP Request-Response Cycle....209

Response Status Codes....210

An Example GET Request....211

How Servers Operate....213

Simple Web Servers for File Retrieval....213

Dynamic Web Servers for Processing Data....214

The Routing Process....215

Templating....216

PHP Tags....218

Short Echo Tags....219

The Model-View-Controller Architecture....219

Structuring a PHP Web Development Project....221

Summary....224

Exercises....224

11. Creating and Processing Web Forms....226

Basic ClientServer Communication for Web Forms....227

GET vs. POST Requests....228

A Simple Example....230

The filter_input() Function....235

Other Ways to Send Data....237

Sending Noneditable Data Along with Form Variables....237

Processing Mixed Query-String and POST Variables....238

Offering Multiple Submit Buttons....239

Encoding Data in Hyperlinks....242

Other Form Input Types....245

Radio Buttons....246

Checkboxes....247

Single-Selection Lists....251

Multiple-Selection Lists....252

Summary....254

Exercises....254

12. Validating Form Data....256

Writing Custom Validation Logic....257

Managing Multiple Validation Errors....258

Testing for a Valid Zero Value....259

Displaying and Validating Forms in a Single Postback Script....261

Simple Validation Logic....262

Array-Based Validation Logic....266

Summary....269

Exercises....269

13. Organizing a Web Application....270

Front Controllers and the MVC Architecture....271

Separating Display and Logic Files....273

Creating the Front Controller....274

Writing the Display Scripts....274

Moving Website Logic into Functions....276

Designing a Secure Folder Structure....276

Simplifying the Front-Controller Script....277

Writing the Functions....277

Generalizing the Front-Controller Structure....279

Distinguishing Between Requested Pages....280

Building a Multipage Application....280

Summary....288

Exercises....288

Part IV: Storing User Data with Browser Sessions....290

14. Working with Sessions....292

A Web Browser Session....293

The session_start() and session_id() Functions....295

The _SESSION Superglobal Array....296

Updating a Stored Value....297

Unsetting a Value....300

Destroying the Session and Emptying the Session Array....301

Summary....304

Exercises....304

15. Implementing a Shopping Cart....306

The Shopping Cart File Structure....307

Defining the Product List....308

Creating the Products Array....309

Adding CSS....310

Displaying the Star Ratings....311

Creating the Template Script....312

Updating the Index Script....313

Designing the Shopping Cart....314

Creating the Front Controller....315

Managing the Product and Cart Arrays....315

Streamlining the Index Script....317

Creating a Header Template....318

Creating the Cart Display Template....319

Interacting with the Session....323

Updating the Cart-Retrieval Function....323

Implementing Cart-Manipulation Functions....324

Creating the Empty Cart Template....326

Finalizing the Front Controller....327

Adding Display Functions....328

Writing the switch Statement....328

Summary....330

Exercises....331

16. Authentication and Authorization....332

A Simple Login Form....333

Creating a Site with a Login Form....334

Defining the File Structure....335

Creating the Shared Page Content....335

Designing the Page Templates....338

Developing the Login Form....340

Writing the Front Controller....342

Implementing the Logic Functions....343

Creating the Error Page Template....345

Storing Login Data with Sessions....347

Updating the Front Controller....347

Writing the Login Function....348

Updating the Header Template....349

Updating the Banking Page Template....350

Offering a Logout Feature....350

Adding the Logout Function....351

Updating the Front Controller....351

Displaying the Logout Link....351

Displaying the Logged-in Username....352

Retrieving the Username....353

Updating the Navigation Bar....353

Updating the CSS....353

Summary....354

Exercises....354

Part V: Object-Oriented PHP....356

17. Introduction to Object-Oriented Programming....358

Classes and Objects....359

Creating Relationships Between Objects....361

Encapsulation and Information Hiding....362

Superclasses, Inheritance, and Overriding....362

The Flow of Control for Object-Oriented Systems....364

An Example Class Declaration....365

Summary....366

Exercises....367

18. Declaring Classes and Creating Objects....368

Declaring a Class....368

Creating an Object....370

Private Properties with Public Accessor Methods....372

Getting and Setting Private Properties....375

Screening for Invalid Data....375

Overriding Default Class Behavior with Magic Methods....377

Initializing Values with a Constructor Method....377

Converting Objects to Strings....380

Object Variables as References....382

Handling Missing Objects....382

Custom Methods and Virtual Attributes....384

Summary....385

Exercises....386

19. Inheritance....388

Inheritance as Generalization....389

Creating Objects from Subclasses....390

Using Multiple Levels of Inheritance....392

Protected Visibility....393

Abstract Classes....398

Overriding Inherited Methods....399

Augmenting Inherited Behavior....402

Preventing Subclassing and Overriding....405

Declaring a Class final....405

Declaring a Method final....406

Summary....408

Exercises....408

20. Managing Classes and Namespaces with Composer....412

Namespaces....413

Declaring a Classs Namespace....413

Using a Namespaced Class....414

Referencing Namespaces in Class Declarations....415

Composer....417

Installing and Testing Composer....417

Creating the composer.json Configuration File....417

Creating an Autoloader....419

Adding Third-Party Libraries to a Project....421

Where to Find PHP Libraries....423

Summary....424

Exercises....424

21. Efficient Template Design with Twig....426

The Twig Templating Library....427

How Twig Works....428

A Simple Example....429

Manipulating Objects and Arrays in Twig Templates....434

Twig Control Structures....437

Creating a Multipage Website with Twig....439

The File Structure and Dependencies....439

The Application Class....440

The Twig Templates....442

Twig Features to Improve Efficiency....444

Improved Page Styling with CSS....450

Summary....455

Exercises....456

22. Structuring an Object-Oriented Web Application....458

Separating Display and Front-Controller Logic....459

Using Multiple Controller Classes....461

Sharing Controller Features Through Inheritance....466

Summary....469

Exercises....469

23. Error Handling with Exceptions....472

The Basics of Exceptions....473

Throwing an Exception....473

Catching an Exception....477

Ending with a finally Statement....478

Using Multiple Exception Classes....480

Other Built-in Exception Classes....480

Custom Exception Classes....482

Call-Stack Bubbling....485

Summary....487

Exercises....487

24. Logging Events, Messages, and Transactions....490

Built-in PHP Resources for Logging....491

Predefined Constants for Severity Levels....491

Logging Functions....493

The Monolog Logging Library....495

Organizing Logs with Channels....496

Managing Logs According to Severity....497

Logging Exceptions....500

Logging to the Cloud....503

Summary....505

Exercises....505

25. Static Methods, Properties, and Enumerations....506

Storing Class-Wide Information....506

Static Properties vs. Class Constants....511

Utility Classes with Static Members....513

Sharing Resources Across an Application....516

Saving Resources with the Singleton Pattern....519

Enumerations....522

Backed Enums....525

An Array of All Cases....525

Summary....526

Exercises....526

26. Abstract Methods, Interfaces, and Traits....528

From Inheritance to Interfaces....529

Inheriting a Fully Implemented Method from a Superclass....529

Inheriting an Abstract Method....531

Requiring Method Implementations with Interfaces....533

Real-World Applications of Interfaces....540

Caching Approach 1: Using an Array....541

Caching Approach 2: Using a JSON File....545

Caching Approach 3: Creating a Cacheable Interface....547

Traits....552

Declaring Traits....553

Inserting Traits....555

Resolving Trait Conflicts....556

What to Use When?....556

Summary....558

Exercises....558

Part VI: Database-Driven Application Development....560

27. Introduction to Databases....562

Relational Database Basics....563

Database Management Systems....564

Structured Query Language....565

Databases and Web Application Architecture....566

Object-Oriented Programming....566

The Model-View-Controller Pattern....569

Summary....570

Exercises....570

28. Database Programming with the PDO Library....572

The PDO Library....573

A Simple Database-Driven Web Application....574

Setting Up the Database Schema....574

Writing the PHP Classes....578

Switching from MySQL to SQLite....582

A Multipage Database-Driven Web Application....584

Managing the Product Information....586

Implementing the Controller Logic....589

Designing the Templates....592

Summary....597

Exercises....597

29. Programming Crud Operations....600

Deleting Data....601

Deleting Everything from a Table....601

Deleting Individual Items by ID....604

Creating New Database Entries....608

Adding Products Through a Web Form....609

Highlighting the Newly Created Product....613

Updating a Database Entry....616

Avoiding Double Form Submission with Redirects....621

Summary....624

Exercises....625

30. Orm Libraries and Database Security....626

Simplifying Database Code with an ORM Library....627

Adding an ORM Library to a Project....629

Moving Database Credentials to a .env File....629

Relegating Product Operations to the ORM Library....630

Adding a New Database Table....632

Security Best Practices....639

Storing Hashed Passwords....639

Verifying Hashed Passwords at Login....640

Securing Database Credentials....646

The Doctrine ORM Library....646

Removing the Previous ORM Library....646

Adding Doctrine....647

Verifying That Doctrine Is Working....648

Creating Database Tables....649

Adding Records to a Table....652

Integrating Doctrine into the Application Code....653

Creating Foreign-Key Relationships....655

Summary....660

Exercises....660

31. Working with Dates and Times....662

The ISO 8601 Standard....663

Creating Dates and Times....664

Formatting the Date-Time Information....665

Using DateTimeImmutable vs. DateTime....666

Manipulating Dates and Times....668

Using Date-Time Intervals....670

Looping at Regular Intervals....671

Time Zones....672

Daylight Saving Time....675

Epochs and Unix Time....677

Date-Time Information in a Web Application....678

The Application Class....679

The Supporting Classes....681

The Templates....684

MySQL Dates....686

Summary....692

Exercises....693

A. Installing PHP....694

macOS....694

Linux....695

Windows....696

AMP Installations....698

B. Database Setup....700

MySQL....700

macOS and Windows....700

Linux....701

SQLite....702

Confirming the MySQL and SQLite Extensions....702

C. Replit Configuration....704

Changing the PHP Version....705

Adding the Composer Tool....706

Using the SQLite Database System....706

Serving Pages from the public Directory....707

Index....710

Back Cover....730

Tired of cobbling together PHP solutions from scattered online tutorials? Frustrated by outdated PHP practices that leave your code vulnerable and hard to maintain? Whether you’re building your first dynamic website or modernizing legacy systems, PHP Crash Course gives you a complete, practical foundation for writing professional web applications.

In this comprehensive, example-driven guide, you’ll learn how to:

• Write clean, maintainable PHP code using modern language features and best practices
• Build secure web applications that protect against common vulnerabilities
• Master database integration using PDO and object-relational mappings (ORMs)
• Implement professional features like shopping carts and user authentication
• Structure applications using object-oriented programming and model-view-controller (MVC) patterns
• Leverage powerful tools like Composer and Twig to accelerate development

Starting with PHP fundamentals, you’ll progress through six carefully crafted sections covering essential patterns, security best practices, database integration, and advanced concepts like object-oriented programming. Each chapter builds on real-world examples, giving you the skills to solve common development challenges.

Whether you’re a complete beginner or an experienced developer looking to modernize your PHP skills, PHP Crash Course gives you everything you need to build professional, dynamic websites with confidence.

Includes setup instructions for Windows, macOS, and Linux, and configuration details for Replit, the free online development environment.