David Powers
PHP 7 SolutionsDynamic Web Design Made Easy4th ed.
David Powers
London, UK
ISBN 978-1-4842-4337-4e-ISBN 978-1-4842-4338-1
https://doi.org/10.1007/978-1-4842-4338-1
© David Powers 2019
This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed.
Trademarked names, logos, and images may appear in this book. Rather than use a trademark symbol with every occurrence of a trademarked name, logo, or image we use the names, logos, and images only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights.
While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.
Distributed to the book trade worldwide by Springer Science+Business Media New York, 233 Spring Street, 6th Floor, New York, NY 10013. Phone 1-800-SPRINGER, fax (201) 348-4505, e-mail [email protected], or visit www.springeronline.com. Apress Media, LLC is a California LLC and the sole member (owner) is Springer Science + Business Media Finance Inc (SSBM Finance Inc). SSBM Finance Inc is a Delaware corporation.

In memory of Toshiko, my friend, companion, and wife of many years

Introduction

I’ve always felt concerned about unduly raising readers’ expectations with the subtitle of this book, Dynamic Web Design Made Easy. PHP is not difficult, but nor is it like an instant cake mix: just add water and stir. Every web site is different, so it’s impossible to grab a script, paste it into a web page, and expect it to work. My aim is to help web designers with little or no knowledge of programming gain the confidence to dive into the code and adjust it to their own requirements.

You don’t need any previous experience of PHP or another programming language to be able to use this book; but it does move at a fast pace. After the first few chapters, you start working with relatively advanced features of the language. Don’t let that put you off. Regard it as a challenge. This book is called PHP Solutions for a reason—to provide solutions to practical problems rather than offer a series of meaningless exercises.

How you use the book will depend on your level of experience. If you’re new to PHP and programming, start at the beginning and work your way gradually through the book. It’s organized as a logical sequence with each chapter building on knowledge and skills gained in previous ones. When describing the code, I try to explain what it does in plain language. I avoid jargon, but not technical terms (each new term is described briefly when it’s first encountered). If you have more experience with PHP, you can probably jump straight into whatever interests you. Even if the code makes sense to you without my explanations, I hope the text throws light onto my thought processes when solving a problem with PHP.

A Small but Significant Change

There’s a subtle difference in the title of this edition. We’ve snuck a 7 into it. The previous editions were called simply PHP Solutions; but my editor and I decided to make it crystal clear that this edition focuses exclusively on PHP 7, the only version of PHP that’s currently supported. One of the great advantages of PHP 7, apart from greatly improved speed, is that it’s almost completely backward compatible with PHP 5—in other words, virtually all the code that ran on PHP 5 can be transferred seamlessly to PHP 7. However, it doesn’t work the other way round. This book makes use of a lot of features that are new to PHP 7. So, if you try to run the code in PHP 7 Solutions on an old server still running PHP 5, you’ll soon run into problems.

Because hosting companies are often slow to upgrade the version of PHP that they offer, previous editions of this book provided workarounds for older versions of PHP. This time, I don’t. For some readers, this means code that works perfectly in a local testing environment is likely to break when it’s uploaded to a remote server. As of mid-2019, more than two out of every three web servers running PHP are still using PHP 5, even though all official support for PHP 5 ended in December 2018. Not even the original version of PHP 7 (7.0) is supported any longer. The code in this book was developed on PHP 7.3, although with one minor exception noted in Chapter 10 (complete with workaround), everything will run on PHP 7.2 or later.

PHP isn’t like that old car you’ve been running for years and doesn’t need changing as long as you give it sufficient love and oil. PHP is constantly being updated, not only to add new features but also to fix bugs and security issues. Even if you’re not interested in the new features, you should be interested in security fixes. The Internet can be a wild place with lots of unsavory characters trying to find exploitable holes in web sites. This book contains a lot of advice on security, but it can’t protect you from security issues that are uncovered in the PHP core. Making sure that your remote server is kept up to date is an indispensable insurance policy to minimize your risks. And it shouldn’t cost you any extra because PHP is free (although hosting companies charge for their services).

If you really need code that’s compatible with PHP 5, check out the third edition of this book. Better still, make the move to the most up-to-date version of PHP.

What Else Is New in This Edition?

This edition closely follows the structure of previous editions and it uses the same Japan Journey case study, so at first glance it might not seem as though much has changed. However, every page has been revised with the aim of making the text clearer. More important, the code has been extensively reviewed and updated. The Upload and ThumbnailUpload classes in Chapters 9 and 10 have been radically rewritten to make them simpler and more robust. There’s a completely new chapter on working with arrays; and the chapter on writing PHP scripts has been split into two. Chapter 3 is now a quick introduction to PHP for newcomers, while Chapter 4 acts as a quick PHP reference for beginners and more experienced readers alike. Chapter 4 has been expanded to cover new features in PHP 7.

The chapters on working with a MySQL or MariaDB database have been revised to make the code more secure. I’ve also added a PHP solution highlighting potential problems with using the superglobal variable $_SERVER['PHP_SELF'] and suggesting a robust workaround.

Using the Example Files

All the files necessary for working through this book can be downloaded from the Apress web site via the Download Source Code button located at www.apress.com/9781484243374 .

Set up a PHP development environment, as described in Chapter 2 . Unzip the files and copy the phpsols-4e folder and all its contents into your web server’s document root. The code for each chapter is in a folder named after the chapter: ch01 , ch02 , and so on. Follow the instructions in each PHP solution, and copy the relevant files to the site root or the work folder indicated.

Where a page undergoes several changes during a chapter, I have numbered the different versions like this: index_01.php , index_02.php , and so on. When copying a file that has a number, remove the underscore and number from the filename, so index_01.php becomes index.php . If you are using a program that prompts you to update links when moving files from one folder to another, do not update them. The links in the files are designed to pick up the right images and style sheets when located in the target folder. I have done this so you can use a file comparison utility to check your files against mine.

If you don’t have a file comparison utility, I strongly urge you to install one. It will save you hours of head scratching when trying to spot the difference between your version and mine. A missing semicolon or mistyped variable can be hard to spot in dozens of lines of code. Windows users can download WinMerge for free from http://winmerge.org/ . I use Beyond Compare ( www.scootersoftware.com ), which is now available for Windows, macOS, and Linux. It’s not free but is excellent and reasonably priced. BBEdit on a Mac includes a file comparison utility. If you’re comfortable using Terminal on a Mac, the diff utility is installed by default.

Layout Conventions

To keep this book as clear and easy to follow as possible, the following text conventions are used throughout:

  • Important words or concepts are normally highlighted on the first appearance in bold type .

  • Code is presented in fixed-width font .

  • New or changed code is normally presented in bold fixed-width font .

  • Pseudocode and variable input are written in italic fixed-width font .

  • Menu commands are written in the form Menu ➤ Submenu ➤ Submenu.

  • Where I want to draw your attention to something, I’ve highlighted it, like this:

Ahem, don’t say I didn’t warn you.

Acknowledgments

Many people have contributed to this book, each one helping improve it as it has moved over four editions. I’m particularly grateful to Chris Mills, the editor of the first edition, whose idea it was to move away from the cookbook formula of isolated solutions that left the reader with little or no idea about the practical use of a technique. Chris’s successors, Ben Renow-Clarke (for the second and third editions) and Mark Powers (for this edition), have both provided a light touch, nudging me in the right direction and forgiving my late delivery times. By the way, if you think we’re keeping it in the family, Mark is no relation in spite of his splendid surname.

A really big thank you is due to the technical reviewers of this edition, Rob Aley and Massimo Nardone. By the time a book gets to its fourth edition, an author hopes to get something of a free ride, expecting all the problems to have been sorted out in previous editions. Fortunately for you, the reader, they subjected my code and text to almost forensic analysis, making really helpful suggestions. As a result, the book has been greatly improved. Any errors or inconsistencies that remain are my responsibility alone.

Thanks are also due to everyone involved in the production chain at Apress. A book would never see the light of day without their diligent work behind the scenes.

Finally, I would like to pay tribute to my late wife, Toshiko, who put up with me disappearing for hours on end working on the previous editions of this book. We should have spent more time together. Miss you.

Contents

Chapter 1:​ What Is PHP—And Why Should I Care?​ 1
How PHP has Grown 2
How PHP Makes Pages Dynamic 2
Creating pages that think for themselves 4
How Hard is PHP to Use and Learn?​ 4
Can I Just copy and paste the code?​ 5
How safe is PHP?​ 5
What Software Do I Need to Write PHP?​ 5
What to Look for when choosing a PHP editor 5
So, Let’s Get on with It… 6
Chapter 2:​ Getting Ready to Work with PHP 7
Checking Whether Your Web Site Supports PHP 7
Deciding Where to Test Your Pages 8
What You Need for a Local Test Environment 9
Individual Programs or an All-in-one Package?​ 9
Setting Up on Windows 9
Getting Windows to Display Filename Extensions 9
Choosing a Web Server 10
Installing an All-in-one Package on Windows 10
Setting Up on macOS 10
Installing MAMP 10
Testing and Configuring MAMP 11
Where to Locate Your PHP Files (Windows and Mac) 13
Using Virtual Hosts 13
Checking Your PHP Settings 14
Displaying the Server Configuration with phpinfo() 14
Editing php.​ini 16
What’s Next?​ 17
Chapter 3:​ How to Write PHP Scripts 19
PHP:​ The Big Picture 19
Telling the Server to Process PHP 20
Embedding PHP in a Web Page 20
Storing PHP in an External File 21
Using Variables to Represent Changing Values 21
Ending commands with a semicolon 24
Commenting Scripts 24
Using Arrays to Store Multiple Values 25
PHP’s Built-in Superglobal Arrays 26
Understanding When to Use Quotes 27
Making Decisions 29
Making Comparisons 31
Using indenting and Whitespace for Clarity 31
Using Loops for Repetitive Tasks 32
Using Functions for Preset Tasks 32
Displaying PHP Output 33
Understanding PHP Error Messages 35
PHP Quick Checklist 36
Chapter 4:​ PHP:​ A Quick Reference 39
Using PHP in an Existing Web Site 39
Data Types in PHP 39
Checking the Data Type of a Variable 41
Explicitly Changing a Variable’s Data Type 41
Checking whether a variable has been Defined 42
Doing Calculations with PHP 42
Arithmetic Operators 42
Using the Increment and Decrement Operators 43
Determining the order of calculations 43
Combining Calculations and Assignment 44
Adding to an Existing String 44
All You Ever Wanted to Know about Quotes—and More 45
How PHP Treats Variables Inside Strings 45
Using Escape Sequences Inside Double Quotes 45
Embedding Associative Array Elements in a String 46
Avoiding the Need to Escape Quotes with Heredoc Syntax 46
Creating Arrays 48
Building an Indexed Array 48
Building an Associative Array 49
Creating an Empty Array 49
Multidimensional​ Arrays 50
Using print_​r() to Inspect an Array 50
The Truth According to PHP 51
Explicit Boolean Values 51
Implicit Boolean (“truthy” and “falsy”) Values 52
Making Decisions by Comparing Two Values 52
Testing More than One Condition 53
Using the switch Statement for Decision Chains 54
Using the Ternary Operator 55
Setting a Default Value with the Null Coalescing Operator 55
Executing Code Repeatedly with a Loop 56
Loops using While and Do .​ .​ .​ While 56
The Versatile for Loop 57
Looping through Arrays and Objects with Foreach 58
Breaking Out of a Loop 59
Modularizing Code with Functions 59
Passing values to functions 60
Setting default values for arguments 60
Variable scope—Functions as black boxes 61
Returning values from functions 62
Generators—a special type of function that keeps on giving 62
Passing by reference—Changing the value of an argument 63
Functions that accept a variable number of arguments 64
Where to locate custom-Built functions 65
Understanding PHP classes and objects 65
Optionally specifying Data Types for classes and functions 65
Handling errors and exceptions 67
Creating new variables dynamically 68
Now to the Solutions 69
Chapter 5:​ Lightening Your Workload with Includes 71
Including Code from External Files 71
Introducing the PHP Include Commands 72
Where PHP Looks for Include Files 72
Choosing the Right Filename Extension for Includes 76
Creating Pages with Changing Content 87
Preventing errors with Include Files 96
Suppressing Error Messages on a Live Web Site 97
Why can’t I Use Site-root-relative Links with PHP Includes?​ 102
Choosing Where to locate Your Include Files 103
Security Considerations with Includes 104
Adjusting Your include_​path 104
Chapter Review 107
Chapter 6:​ Bringing Forms to Life 109
How PHP Gathers Information from a Form 109
Understanding the Difference between post and get 111
Getting Form Data with PHP Superglobals 114
Processing and Validating User Input 114
Creating a reusable script 114
Preserving user input when a form is incomplete 122
Filtering Out Potential Attacks 125
Sending Email 127
Using additional email Headers Safely 127
Handling Multiple-Choice Form Elements 135
PHP Solution 6-7:​ Handling Radio Button Groups 137
Chapter Review 145
Chapter 7:​ Using PHP to Manage Files 147
Checking that PHP can Open a File 147
Creating a Folder Outside the Server Root for Local Testing on Windows 148
Configuration Settings that Affect File Access 148
Reading and Writing Files 149
Reading Files in a single Operation 149
Opening and closing Files for Read/​Write Operations 153
Exploring the File System 162
Inspecting a folder with scandir() 163
Inspecting the Contents of a Folder with FilesystemIterat​or 163
Restricting File Types with the RegexIterator 166
Accessing Remote Files 170
Consuming News and Other RSS Feeds 171
Using SimpleXML 172
Creating a Download Link 176
PHP Solution 7-6:​ Prompting a User to Download an Image 176
Chapter Review 178
Chapter 8:​ Working with Arrays 179
Modifying Array Elements 179
PHP Solution 8-1:​ Modify Array Elements with a Loop 180
PHP Solution 8-2:​ Modify array elements with array_​walk() 182
PHP Solution 8-3:​ Modify array elements with array_​map() 184
Merging Arrays 187
Using the Array Union Operator 187
Using array_​merge() and array_​merge_​recursive() 189
Merging Two Indexed Arrays into an Associative Array 191
Comparing Arrays 192
PHP Solution 8-4:​ Joining an Array with Commas 193
Sorting Arrays 196
PHP Solution 8-5:​ Custom Sorting with the Spaceship Operator 198
Complex Sorting with array_​multisort() 200
PHP Solution 8-6:​ Sorting a Multidimensional​ Array with array_​multisort() 202
PHP Solution 8-7:​ Finding All Permutations of an Array 204
Processing Array Data 205
PHP Solution 8-8:​ Building Nested Lists Automatically 205
PHP Solution 8-9:​ Extracting Data from JSON 209
Automatically Assigning Array Elements to Variables 213
Using the extract() Function 214
Using list() 214
Using Array Shorthand Syntax for list() 215
PHP Solution 8-10:​ Using a Generator to Process a CSV File 215
Unpacking Arguments from an Array with the Splat Operator 217
PHP Solution 8-11:​ Processing a CSV File with the Splat Operator 218
Chapter Review 220
Chapter 9:​ Uploading Files 221
How PHP Handles File Uploads 221
Checking Whether your Server Supports Uploads 222
Adding a File Upload Field to a Form 223
Understanding the $_​FILES Array 223
Establishing an Upload Directory 226
Uploading Files 227
Moving the Temporary File to the Upload Folder 227
Creating a PHP File Upload Class 230
Defining a PHP Class 231
Checking Upload Errors 238
Changing Protected Properties 242
Uploading Multiple Files 249
How the $_​FILES Array Handles Multiple Files 249
Using the Upload Class 255
Points to Watch with File Uploads 255
Chapter Review 256
Chapter 10:​ Generating Thumbnail Images 257
Checking Your Server’s Capabilities 257
Manipulating Images Dynamically 258
Making a Smaller Copy of an image 258
Resizing an Image Automatically on Upload 277
Extending a Class 277
Using the ThumbnailUpload Class 283
Chapter Review 284
Chapter 11:​ Pages That Remember:​ Simple Login and Multipage Forms 285
What Sessions are and How They Work 285
Creating PHP Sessions 288
Creating and Destroying Session Variables 288
Destroying a Session 289
Regenerating the Session ID 289
The “Headers already sent” Error 289
Using Sessions to Restrict Access 290
PHP Solution 11-1:​ A Simple Session Example 290
Using File-based Authentication 294
Making Passwords Secure 294
Setting a Time Limit on Sessions 314
PHP Solution 11-8:​ Ending a Session After a Period of Inactivity 315
Passing Information through Multipage Forms 317
PHP Solution 11-9:​ Using Sessions for a Multipage Form 318
Chapter Review 323
Chapter 12:​ Getting Started with a Database 325
MySQL or MariaDB?​ 325
How a Database Stores Information 326
How Primary Keys Work 327
Linking Tables with Primary and Foreign Keys 328
Breaking Down Information into Small Chunks 328
Checkpoints for Good Database Design 329
Using a Graphical Interface 329
Launching phpMyAdmin 330
Setting Up the phpsols Database 331
MySQL Naming Rules 331
Using phpMyAdmin to Create a New Database 332
Creating Database-specific User Accounts 333
Creating a Database Table 336
Inserting Records into a Table 338
Creating an SQL File for Backup and Data Transfer 342
Choosing the Right Data Type in MySQL 346
Storing Text 346
Storing Numbers 347
Storing Dates and Times 347
Storing Predefined Lists 348
Storing Binary Data 348
Chapter Review 348
Chapter 13:​ Connecting to a Database with PHP and SQL 349
Checking Your Remote Server Setup 349
How PHP Communicates with a Database 350
Connecting with the MySQL Improved Extension 351
Connecting with PDO 351
PHP Solution 13-1:​ Making a Reusable Database Connector 352
Sanitizing Text Results from a Database 354
Querying the Database and Displaying the Results 355
Using SQL to Interact with a Database 362
Writing SQL Queries 362
Refining the Data Retrieved by a SELECT Query 364
Understanding the Danger of SQL Injection 368
PHP Solution 13-6:​ Inserting an integer from User Input into a Query 369
Using Prepared Statements for User Input 372
Embedding Variables in MySQLi Prepared Statements 373
Embedding Variables in PDO Prepared Statements 378
Chapter Review 386
Chapter 14:​ Creating a Dynamic Photo Gallery 387
Why Not Store Images in a Database?​ 388
Planning the Gallery 388
Converting the Gallery Elements to PHP 390
PHP Solution 14-1:​ Displaying the First Image 390
Building the Dynamic Elements 393
Passing Information Through a Query String 393
Creating a Multicolumn Table 397
Paging Through a Long Set of Records 399
Chapter Review 406
Chapter 15:​ Managing Content 407
Setting Up a Content Management System 407
Creating the Blog Database Table 408
Creating the Basic Insert and Update Form 409
Inserting New Records 411
Linking to the Update and Delete Pages 415
Updating Records 418
Deleting Records 428
Reviewing the Four Essential SQL Commands 429
SELECT 429
INSERT 431
UPDATE 432
DELETE 432
Security and Error Messages 432
Chapter Review 433
Chapter 16:​ Formatting Text and Dates 435
Displaying a Text Extract 435
Extracting a Fixed Number of Characters 435
Ending an Extract on a Complete Word 437
Extracting the First Paragraph 438
Displaying Paragraphs 438
Extracting Complete Sentences 440
Let’s Make a Date 443
How MySQL Handles Dates 444
Inserting Dates into MySQL 447
Working with Dates in PHP 453
Chapter Review 468
Chapter 17:​ Pulling Data from Multiple Tables 469
Understanding Table Relationships 469
Linking an Image to an Article 471
Altering the Structure of an Existing Table 471
Inserting a Foreign Key in a Table 473
Selecting Records from Multiple Tables 479
Finding Records that Don’t have a Matching Foreign Key 485
Creating an intelligent Link 486
Chapter Review 487
Chapter 18:​ Managing Multiple Database Tables 489
Maintaining Referential Integrity 489
Support for Transactions and Foreign-key Constraints 490
Inserting Records into Multiple Tables 493
Creating a Cross-reference Table 494
Getting the Filename of an Uploaded Image 495
Adapting the Insert Form to Deal with Multiple Tables 496
Updating and Deleting Records in Multiple Tables 508
Updating Records in a Cross-reference Table 508
Treating Multiple Queries as a Block in a Transaction 511
Preserving Referential Integrity on Deletion 519
Creating Delete Scripts with Foreign-key Constraints 523
Creating Delete Scripts without Foreign-key Constraints 524
Chapter Review 525
Chapter 19:​ Authenticating Users with a Database 527
Choosing a Password Storage Method 527
Using Password Hashing 528
Creating a Table to Store Users’ Details 528
Registering New Users in the Database 528
Using Secret-Key Encryption 536
Creating the table to store Users’ Details 536
Registering New Users 536
User Authentication with Two-way Encryption 538
Decrypting a Password 539
Updating User Details 540
Where Next?​ 540
Index 541

About the Author and About the Technical Reviewers

About the Author

David Powers

is the author of more than 30 highly successful video training courses and books on PHP. He began his professional career as a radio and TV journalist for the BBC, spending a large part of it in Japan reporting on the rise and collapse of the bubble economy. His background of reporting on complex issues in plain, jargon-free language reveals itself in his writing about PHP and web development.

David first became involved with web development in the early 1990s as Editor of BBC Japanese TV. With no marketing budget, he developed a bilingual web site to promote the channel. After leaving the BBC, he went on to develop a bilingual online database for an international consultancy, as well as teaching web development courses at two universities in the UK. In addition to writing and creating video training courses, he’s a Trustee of a charity in North London that provides educational facilities for retired people and those no longer in full-time employment.

 

About the Technical Reviewers

Rob Aley

has been programming commercially and academically in a variety of programming languages, with over 10 years of PHP experience since graduating in Computer Science from the University of Leeds in 1999.

Having had a varied career working in industries from coffee to condoms, as well as doing freelance software development, Rob is now a “Database Programmer” at the University of Oxford working in healthcare-related data analysis. He uses PHP almost exclusively now, out of choice.

When he’s not working or writing books, he spends time with his wife, three young children, and most importantly his cat.

 
Massimo Nardone

has more than 24 years of experience in Security, Web and Mobile development, and Cloud and IT Architecture. His true IT passions are Security and Android.

He has been programming and teaching how to program with Android, Perl, PHP, Java, VB, Python, C/C++, and MySQL for more than 20 years.

He holds a Master of Science in Computing Science from the University of Salerno, Italy.

He has worked as a Project Manager, Software Engineer, Research Engineer, Chief Security Architect, Information Security Manager, PCI/SCADA Auditor, and Senior Lead IT Security/Cloud/SCADA Architect for many years.

His technical skills include Security, Android, Cloud, Java, MySQL, Drupal, Cobol, Perl, Web and Mobile development, MongoDB, D3, Joomla, Couchbase, C/C++, WebGL, Python, Pro Rails, Django CMS, Jekyll, Scratch, and so on.

He worked as Visiting Lecturer and Supervisor for exercises at the Networking Laboratory of the Helsinki University of Technology (Aalto University). He holds four international patents (PKI, SIP, SAML, and Proxy areas).

He currently works as Chief Information Security Officer (CISO) for Cargotec Oyj and he is member of ISACA Finland Chapter Board.

Massimo has reviewed more than 45 IT books for different publishers and has coauthored Pro JPA in Java EE 8 (Apress, 2018), Beginning EJB in Java EE 8 (Apress, 2018), and Pro Android Games (Apress, 2015).

 
..................Content has been hidden....................

You can't read the all page of ebook, please click here login for view all page.
Reset
18.188.218.184