Wordpress Web Application Development - Third Edition

By Rakhitha Nimesh Ratnayake

About This Book

• Develop powerful web applications rapidly with WordPress
• Explore the significant features and improvements introduced in WordPress 4.7 by learning the numerous tips and techniques in this book.
• Unleash the power of REST API endpoints to make your interaction with websites new and innovative.

Who This Book Is For

This book is targeted at WordPress developers and designers who want to develop quality web applications within a limited time frame and maximize their profits. A prior knowledge of basic web development and design is assumed.

• Language: English
• Publisher: Packt Publishing
• Release date: May 30, 2017
• ISBN: 9781787124752

Rakhitha Nimesh Ratnayake

Rakhitha Nimesh Ratnayake is a freelance web developer, writer, and an open source enthusiast. He also provides technical consultation on large scale web applications to one of the leading software development firms in SriLanka. Rakhitha is the creator of www.innovativephp.com, where he writes tutorials on the latest web development and design technologies. He is also a regular contributor to a number of popular websites such as 1stwebdesigner, the Tuts+ network, and the SitePoint network. Building Impressive Presentations with impress.js was his first book, also published by Packt Publishing. In his spare time, he likes to watch cricket and spend time with his family. Make sure you visit him online at www.innovativephp.com and follow him on Google+ at http://goo.gl/UiEf5B.

Book preview

Title Page

WordPress Web Application Development

Third Edition

Build rapid web applications with cutting-edge technologies using WordPress

Rakhitha Nimesh Ratnayake

BIRMINGHAM - MUMBAI

Copyright

WordPress Web Application Development

Third Edition

Copyright © 2017 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: November 2013

Second edition: May 2015

Third edition: May 2017

Production reference: 1260517

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham 

B3 2PB, UK.

ISBN 978-1-78712-680-0

www.packtpub.com

Credits

About the Author

Rakhitha Nimesh Ratnayake is a freelance web developer, writer, and open source enthusiast. He has over 7 years of experience in developing WordPress applications and plugins. He develops premium WordPress plugins for individual clients and the CodeCanyon marketplace. User Profiles Made Easy and WP Private Content Plus are the most popular plugins developed by him. Rakhitha is the creator of, where he shares his latest WordPress plugins. He is also a regular contributor to a number of popular websites, such as 1st webdesigner, the Tuts+ network, and the SitePoint network. Building Impressive Presentations with impress.js was his first book, which was published by Packt Publishing. He is also the author of the first and second editions of WordPress Web Application Development. In his spare time, he likes to watch cricket and spend time with his family.

I would like to thank my loving wife, Dulari, my parents, and my wife’s parents for the help and encouragement provided throughout this book.

I would also like to thank Packt Publishing, especially Senior Acquisition Editor, Reshma Raman, for inviting me to write this book, Content Development Editor, Sreeja Nair, and the reviewers for providing honest feedback to improve this book.

Finally, I would like to thank you for reading my book and being one of the most important people who helped me make this book a success.

About the Reviewer

Alex Bachuk is a web developer with over 9 years of experience, especially in custom JavaScript and WordPress web applications. Alex has been working with WordPress since Version 2.5 and has worked on projects ranging from a single-page website to interactive web applications and social platforms. 

These days, Alex mostly works on Node.js and React.js applications. He is the founder of the EcmaStack.com agency and founder of a timesheet and invoicing application, www.timebooklet.com. 

Alex organizes and talks at WordPress, Meteor.js, and GraphQL meetups in New York City. In his free time, he likes to spend time with his family and travel the world.

www.PacktPub.com

For support files and downloads related to your book, please visit www.PacktPub.com.

Did you know that Packt offers eBook versions of every book published, with PDF and ePub files available? You can upgrade to the eBook version at www.PacktPub.com and as a print book customer, you are entitled to a discount on the eBook copy. Get in touch with us at [e-mail] for more details.

At www.PacktPub.com, you can also read a collection of free technical articles, sign up for a range of free newsletters and receive exclusive discounts and offers on Packt books and eBooks.

https://www.packtpub.com/mapt

Get the most in-demand software skills with Mapt. Mapt gives you full access to all Packt books and video courses, as well as industry-leading tools to help you plan your personal development and advance your career.

Why subscribe?

Fully searchable across every book published by Packt

Copy and paste, print, and bookmark content

On demand and accessible via a web browser

Customer Feedback

Thanks for purchasing this Packt book. At Packt, quality is at the heart of our editorial process. To help us improve, please leave us an honest review on this book's Amazon page at https://www.amazon.com/dp/1787283739.

If you'd like to join our team of regular reviewers, you can e-mail us at [e-mail]. We award our regular reviewers with free eBooks

Table of Contents

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

WordPress as a Web Application Framework

WordPress as a CMS

WordPress as a web application framework

The MVC versus event-driven architecture

Simplifying development with built-in features

User management

Media management

Template management

Database management

Routing

XML-RPC API

REST API

Caching

Scheduling

Plugins and widgets

Themes

Actions and filters

The admin dashboard

Identifying the components of WordPress

The role of WordPress themes

Structure of a WordPress page layout

Customizing the application layout

The role of the admin dashboard

The admin dashboard

Posts and pages

Users

Appearance

Settings

The role of plugins

The role of widgets

A development plan for the forum management application

Application goals and target audience

Planning the application

User roles of the application

Planning application features and functions

Understanding limitations and sticking to guidelines

Building a question-answer interface

Prerequisites for building a question-answer interface

Creating questions

Customizing the comments template

Changing the status of answers

Saving the status of answers

Generating a question list

Enhancing features of the questions plugin

Customizing the design of questions

Categorizing questions

Approving and rejecting questions

Adding star rating to answers

Summary

Implementing Membership Roles, Permissions, and Features

Introduction to user management

Preparing the plugin

Getting started with user roles

Creating application user roles

The best action for adding user roles

Knowing the default roles of WordPress

Choosing between default and custom roles

Scenario 1

Scenario 2

Removing existing user roles

Understanding user capabilities

Creating your first capability

Understanding default capabilities

Registering application users

Implementing frontend registration

Shortcode implementation

Pros and cons of using shortcodes

Page template implementation

Pros and cons of page templates

Custom template implementation

Building a simple router for a user module

Creating the routing rules

Adding query variables

Flushing the rewriting rules

Controlling access to your functions

The advantages of using the do_action function

Creating custom templates

Designing the registration form

Planning the registration process

Handling registration form submission

Exploring the registration success path

Automatically logging in the user after registration

Activating system users

Creating a login form in the frontend

Handling login form submission

Checking whether we implemented the process properly

Essential user management features for web applications

Frontend login and registration

Custom profile fields

Private data

Search and member list

Frontend profile

Implementing user management features with popular plugins

BuddyPress

User Profiles Made Easy

User Role Editor

Time to practice

Summary

Planning and Customizing the Core Database

Understanding the WordPress database

Exploring the role of existing tables

User-related tables

Post-related tables

Term-related tables

Other tables

Adapting existing tables in web applications

User-related tables

Post-related tables

Scenario 1 &-; an online shopping cart

Scenario 2 &-; a hotel reservation system

Scenario 3 &-; a project management application

Term-related tables

Other tables

Extending the database with custom tables

Planning the forum application tables

Types of table in web applications

Creating custom tables

Querying the database

Querying the existing tables

Inserting records

Updating records

Deleting records

Selecting records

Querying the custom tables

Working with posts

Extending the WP_Query class for applications

Introduction to WordPress query classes

The WP_User_Query class

The WP_Comment_Query class

Other query classes

Limitations and considerations

Transaction support

Post revisions

How do you know whether to enable or disable revisions?

Autosaving

Using meta tables

Summary

Building Blocks of Web Applications

Introduction to custom content types

The role of custom post types in web applications

Planning custom post types for an application

Forums

Topics

Implementing custom post types for a forum application

Implementing the custom post type settings

Creating forum and topic classes

Assigning permissions to forums and topics

Creating custom taxonomies for topic categories and topic tags

Assigning permissions to the topic tags

Introduction to custom fields with meta boxes

What is a template engine?

Building a simple custom template loader

Creating your first template

Comparing the template loader and template engine

Persisting custom field data

Customizing custom post type messages

Introduction to post type templates

Creating and using a post type template

Introducing custom post type relationships

Pods framework for custom content types

Should you choose Pods for web development?

Implementing custom post type features with popular plugins

Custom Post Type UI

Toolset Types

Time to practice

Summary

Implementing Application Content Restrictions

Introduction to content restrictions

Practical usage of content restrictions

The role of membership in content restrictions

Understanding restriction levels

User roles-based restrictions

User groups-based restrictions

Membership plans-based restrictions

Unique password-based restrictions

Implementing content restrictions in posts/pages

Shortcode-based restrictions

Individual post/page restrictions

Creating a meta box for topic restrictions

Saving topic restriction settings

Verifying individual post/page restrictions

Site lockdown

Enabling restrictions on WordPress core features

Restrictions on posts

Restrictions on searches

Restrictions on menus

Restrictions on widgets

Restrictions on archives

Supplementary content restriction types and techniques

Restrictions on custom generated content

Attachment protection

Social Locker

E-mail subscription

Private page

Useful plugins for content restrictions

Restrict Content

WP Private Content Plus

Membership 2

Time to practice

Summary

Developing Pluggable Modules

A brief introduction to WordPress plugins

Understanding the WordPress plugin architecture

WordPress plugins for web development

Creating reusable libraries with plugins

Planning the template loader plugin

Using the template loader plugin

Handling plugin dependencies

Extensible plugins

Extending plugins with WordPress core actions and filters

Creating the extensible file uploader plugin

Converting file fields with jQuery

Integrating the media uploader to buttons

Extending the file uploader plugin

Customizing the allowed file types

Saving and loading topic files

Extending plugins with custom actions and filters

Pluggable plugins

Tips for using pluggable functions

Tips for developing extendable plugins

Time to practice

Summary

Customizing the Dashboard for Powerful Backends

Understanding the admin dashboard

Customizing the admin toolbar

Removing the admin toolbar

Managing the admin toolbar items

Customizing the main navigation menu

Creating new menu items

Adding features with custom pages

Building options pages

Creating a custom layout for options pages

Building an application options panel

Using the WordPress options API

Using feature-packed admin list tables

Working with default admin list tables

The post list

Creating custom actions for custom posts

Creating custom filters for custom post types

Creating custom post status links

Displaying custom list columns

The user list

The comments list

Building extended lists

Using the admin list table for forum topics

Step 1 &-; defining the custom class

Step 2 &-; defining the instance variables

Step 3 &-; creating the initial configurations

Step 4 &-; implementing the custom column handlers

Step 5 &-; implementing the column default handlers

Step 6 &-; displaying the checkbox for records

Step 7 &-; listing the available custom columns

Step 8 &-; defining the sortable columns of list

Step 9 &-; creating a list of bulk actions

Step 10 &-; retrieving the list data

Step 11 &-; adding a custom list as a menu page

Step 12 &-; displaying the generated list

Managing the subscribe and unsubscribe status

Adding content restrictions to admin list tables

An awesome visual presentation for admin screens

Using existing themes

Using plugin-based third-party admin themes

Creating your own admin theme

The responsive nature of the admin dashboard

Supplementary admin dashboard features

Dashboard widgets

Screen options menu

Help menu

User language control

Time for action

Summary

Adjusting Theme for Amazing Frontends

An introduction to the WordPress application frontend

A basic file structure of the WordPress theme

Understanding the template execution hierarchy

The template execution process of web application frameworks

Web application layout creation techniques

Shortcodes and page templates

Custom templates with custom routing

Using pure PHP templates

The WordPress way of using templates

Direct template inclusion

Theme versus plugin-based templates

Are you planning to create an application-specific theme?

Building the forum application home page

Building the forum list using shortcode

Widgetizing home page

What is a widget?

Widgetizing application layouts

Creating widgets

Designing a home page template

Generating the application frontend menu

Creating a navigation menu

Saving menu item restrictions

Displaying user-specific menus on the frontend

Managing options and widgets with customizer

Adding custom options to the theme customizer

Handling widgets in the theme customizer

Creating pluggable templates

Extending the home page template with action hooks

Customizing widgets to enable extendable locations

Planning action hooks for layouts

Managing custom CSS with live preview

Responsive previews in theme customizer

Time for action

Summary

Enhancing the Power of Open Source Libraries and Plugins

Why choose open source libraries?

Open source libraries inside the WordPress core

Open source JavaScript libraries in the WordPress core

What is Backbone.js?

Understanding the importance of code structuring

Integrating Backbone.js and Underscore.js

Creating a forum user profile page with Backbone.js

Structuring with Backbone.js and Underscore.js

Displaying the topics list on page load

Creating new topics from the frontend

Integrating events to Backbone.js views

Validating and creating new models for the server

Creating new models in the server

Using PHPMailer for custom e-mail sending

Usage of PHPMailer within the WordPress core

Creating a custom version of a pluggable wp_mail function

Loading PHPMailer inside plugins and creating custom functions

Implementing user authentication with OpenAuth

Configuring login strategies

Implementing LinkedIn account authentication

Verifying a LinkedIn account and generating a response

Building a LinkedIn app

The process of requesting the strategies

Initializing the library

Authenticating users to our application

Using third-party libraries and plugins

Using open source plugins for web development

Using plugins for checking security of other plugins

Time for action

Summary

Listening to Third-Party Applications

Introduction to APIs

The advantages of having an API

The WordPress XML-RPC API for web applications

Building the API client

Creating a custom API

Integrating API user authentication

Integrating API access tokens

Providing the API documentation

WordPress REST API for web applications

Introduction to WordPress REST API endpoints

Testing GET requests

Testing POST requests

Disabling REST API

Custom content types with REST API

Managing custom routes and endpoints

Creating custom routes and endpoints for forum topics

Creating custom routes and endpoints for custom table data

Building the REST API client

REST API client in the same site

REST API client from external site

REST API authentication and access tokens

Time for action

Summary

Integrating and Finalizing the Forum Management Application

Integrating and structuring the forum application

Integrating the template loader into a user manager

Working with the restructured application

Building the forum page

Displaying forum details

Creating new forum topics

Displaying forum topics

Joining users to forums

Restricting topic creation to forum members

Building forum topic page

Creating forum topic replies

Handling forum topic replies

Understanding other forum features

Updating a user profile with additional fields

Updating the values of the profile fields

Scheduling subscriber notifications

Notifying subscribers through e-mails

Time for action

Final thoughts

Summary

Supplementary Modules for Web Development

Internationalization

Introduction to WordPress translation support

The translation functions in WordPress

Creating plugin translations

Creating the POT file using Eazy Po

Creating and editing translations with PoEdit

Loading language files

Changing the WordPress language

Working with media grid and image editor

Introduction to the post editor

Using the WordPress editor

Keyboard shortcuts

Editor item locations

Highlighting broken links

Video embedding

Lesser-known WordPress features

Caching

Transients

Testing

Security

Performance

P3 - Plugin Performance Profiler plugin

Query monitor plugin

GTmetrix for WordPress

Managing application scripts and styles

Conditionally loading script and styles

Inline script loading

Version control

E-commerce

Creating products with WooCommerce

Migrating WordPress applications

Importing and exporting application content

Introduction to multisite

Time for action

Summary

Configurations, Tools, and Resources

Configuring and setting up WordPress

Step 1&-; downloading WordPress

Step 2 &-; creating the application folder

Step 3 &-; configuring the application URL

Creating a virtual host

Using a localhost

Step 4 &-; installing WordPress

Step 5 &-; setting up permalinks

Step 6 &-; downloading the Responsive theme

Step 7&-; activating the Responsive theme

Step 8 &-; activating the plugin

Step 9 &-; using the application

Open source libraries and plugins

Online resources and tutorials

Preface

The rise of WordPress-powered websites is one of the standout trends in the modern web development world. WordPress has taken over 25% of all the websites in the world. The power of the plugin-based architecture and the flexibility of the built-in features offered by WordPress has made developers use this framework for advanced web development. The official plugin directory contains over forty thousand plugins, covering most of the areas required in application development. Therefore, WordPress becomes one of the top solutions for rapid application development with existing plugins. This book will act as a comprehensive resource for building web applications with this amazing framework.

WordPress Web Application Development is a practical guide focused on incorporating and extending the core WordPress features into typical web application development. This book is structured toward building a complete web application from scratch. With this book, you will learn to use and extend WordPress core features to build a forum management application with the latest trending technologies.

This book follows a example-based approach while discussing each WordPress core modules, for pushing the limits of WordPress to create web applications beyond your imagination.

It begins by exploring the role of existing WordPress core features and discussing the reasons for choosing WordPress for web application development. As we move on, more focus will be put into adapting WordPress features into web applications with the help of an informal use-case-based model for discussing the most prominent built-in features.  Along with core features, you will also learn the integration of new features into existing features through plugins. While striving for web development with WordPress, you will also learn about the integration of popular client-side technologies, such as Backbone.js, Underscore, jQuery, and server-side technologies and techniques such as template engines and OpenAuth integration.

After reading this book, you will possess the ability to develop powerful web applications rapidly within limited time frames with the crucial advantage of benefiting low-budget and time-critical projects.

What this book covers

Chapter 1, WordPress As a Web Application Framework, walks you through the existing modules and techniques to identify their usage in web applications. Identification of WordPress features beyond the conventional CMS and planning the forum management application are the highlights of this chapter.

Chapter 2, Implementing Membership Roles, Permissions, and Features, covers the built-in user management features and user permission concepts. Beginning the development of forum management application, implementing basic user management features such as login, registration and introduction to the MVC process through custom routing are the highlights of this chapter.

Chapter 3, Planning and Customizing Core Database, serves as an extensive guide for understanding the core database structure and the role of custom database tables in web applications. Database querying with built-in functions, creating custom tables, and identifying the limitations in core database tables are the highlights of this chapter.

Chapter 4, Building Blocks of Web Applications, explores the possibilities of using custom post types to extend WordPress posts beyond its conventional usage. Managing custom post types, loading custom templates and learn to speed up development process with existing custom post type plugins are the highlights of this chapter.

Chapter 5, Implementing Application Content Restrictions, focuses on identifying the different user types in applications and the possibilities of providing different content permissions based on those user types. Applying content restrictions to WordPress core features, implementing basic content restriction techniques, and innovating new content restriction strategies are the highlights of this chapter.

Chapter 6, Developing Pluggable Modules, introduces the techniques of creating highly reusable and extensible plugins to enhance the flexibility of web applications. Developing various flexible plugins, handling plugin dependencies, and the use of WordPress actions and filters in applications are the highlight of this chapter.

Chapter 7, Customizing Dashboard for Powerful Backends, walks you through the process of customizing the WordPress admin panel for adding new features as well as changing existing features and design. Building flexible data lists with WordPress admin tables, designing an admin panel with various different techniques, and understanding useful admin section settings are the highlights of this chapter.

Chapter 8, Adjusting Theme for Amazing Frontends, dives into the techniques of designing amazing layouts, thereby opening them for future extension. Widgetizing layouts and building reusable templates are the highlights of this chapter.

Chapter 9, Enhancing the Power of Open Source Libraries and Plugins, explores the use of the latest trending open source technologies and libraries within and outside WordPress core . Integrating open authentication in to your web application, structuring the application at the client side, and identify the proper usage of open source plugins in application development, are the highlights of this chapter.

Chapter 10, Listening to Third-party Applications, demonstrates how to use WordPress XML-RPC API and REST API to create custom API’s for your web application. Building a simple XML-RPC API, identifying support for REST in WordPress core and building custom REST API’s are highlights of this chapter.

Chapter 11, Integrating and Finalizing Forum Management Application, guides you through the integration of modules and adds new features to the existing modules, while refactoring the code developed throughout this book. Identifying the use of proper theme templates and completing the features developed throughout the previous chapters are the highlights of this chapter

Chapter 12, Supplementary Modules for Web Development, introduces the advanced application features such as E-commerce, multisite, and the non-functional WordPress features that defines the quality of a web applications. Introduction to important concepts in application development, such as internationalization, caching, security, performance, version control, site migration, and testing are the highlight of this chapter.

Appendix, Configurations, Tools, and Resources, provides an application setup guide with necessary links to download the plugins and libraries used throughout the book.

What you need for this book

Technically, you need a computer, browser, and an Internet connection with the following working environment:

The Apache web server

PHP Version 5.4 or higher

WordPress Version 4.7.2

MySQL Version 5.6 or higher

Once you have the preceding environment, you can download the Responsive theme from http://wordpress.org/themes/responsive and activate it from the Themes section. Finally, you can activate the plugin developed for this book to get things started.

Refer to Appendix A, Configurations, Tools, and Resources, for the application setup guide, required software, and plugins.

Who this book is for

This book is intended for WordPress developers or designers, who know how to create a basic CMS site and looking for ways to learn the complex web application development in a reusable, maintainable, and modular way. Also, this book is quite useful for non-technical users who want to develop advanced applications by incorporating existing plugins. Basic knowledge of WordPress theme and plugin development is expected, although it’s not a must for experienced PHP developers to go through this book.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: We can set additional parameters to the search query using $query->set function and restrict the search features to limited posts.

A block of code is set as follows:

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

Any command-line input or output is written as follows:

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: Clicking the Next button moves you to the next screen.

Warnings or important notes appear in a box like this.

Tips and tricks appear like this.

Reader feedback

Feedback from our readers is always welcome. Let us know what you think about this book-what you liked or disliked. Reader feedback is important for us as it helps us develop titles that you will really get the most out of.

To send us general feedback, simply e-mail [e-mail], and mention the book's title in the subject of your message.

If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide at www.packtpub.com/authors.

Customer support

Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your purchase.

Downloading the example code

You can download the example code files for this book from your account at http://www.packtpub.com. If you purchased this book elsewhere, you can visit http://www.packtpub.com/support and register to have the files e-mailed directly to you.

You can download the code files by following these steps:

Log in or register to our website using your e-mail address and password.

Hover the mouse pointer on the SUPPORT tab at the top.

Click on Code Downloads & Errata.

Enter the name of the book in the Search box.

Select the book for which you're looking to download the code files.

Choose from the drop-down menu where you purchased this book from.

Click on Code Download.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

WinRAR / 7-Zip for Windows

Zipeg / iZip / UnRarX for Mac

7-Zip / PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Wordpress-Web-Application-Development-Third-Edition. We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Errata

Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you find a mistake in one of our books-maybe a mistake in the text or the code-we would be grateful if you could report this to us. By doing so, you can save other readers from frustration and help us improve subsequent versions of this book. If you find any errata, please report them by visiting http://www.packtpub.com/submit-errata, selecting your book, clicking on the Errata Submission Form link, and entering the details of your errata. Once your errata are verified, your submission will be accepted and the errata will be uploaded to our website or added to any list of existing errata under the Errata section of that title.

To view the previously submitted errata, go to https://www.packtpub.com/books/content/support and enter the name of the book in the search field. The required information will appear under the Errata section.

Piracy

Piracy of copyrighted material on the Internet is an ongoing problem across all media. At Packt, we take the protection of our copyright and licenses very seriously. If you come across any illegal copies of our works in any form on the Internet, please provide us with the location address or website name immediately so that we can pursue a remedy.

Please contact us at [e-mail] with a link to the suspected pirated material.

We appreciate your help in protecting our authors and our ability to bring you valuable content.

Questions

If you have a problem with any aspect of this book, you can contact us at [e-mail], and we will do our best to address the problem.

WordPress as a Web Application Framework

In recent years, WordPress has matured from the most popular blogging platform to the most popular content management system. Thousands of developers around the world are making a living from WordPress design and development. As more and more people are interested in using WordPress, the dream of using this amazing framework for web application development is becoming possible.

The future seems bright as WordPress has already got dozens of built-in features, which can be easily adapted to web application development using slight modifications. Since you are already reading this book, you have to be someone who is really excited to see how WordPress fits into web application development. Throughout this book, we will learn how we can inject the best practices of web development into the WordPress framework to build web applications using a rapid process.

Basically, this book will be important for developers from two different perspectives. On the one hand, beginner to intermediate level WordPress developers can get knowledge of cutting-edge web development technologies and techniques to build complex applications. On the other hand, web development experts who are already familiar with popular PHP frameworks can learn WordPress for rapid application development. So, let's get started!

In this chapter, we will cover the following topics:

WordPress as a CMS

WordPress as a web application framework

Simplifying development with built-in features

Identifying the components of WordPress

Making a development plan for forum management application

Understanding limitations and sticking with guidelines

Building a question-answer interface

Enhancing features of the questions plugin

In order to work with this book, you should be familiar with WordPress themes, plugins, and its overall process. Developers who are experienced in PHP frameworks can work with this book while using the reference sources to learn WordPress. By the end of this chapter, you will have the ability to make the decision to choose WordPress for web development.

WordPress as a CMS

Way back in 2003, WordPress released its first version as a simple blogging platform and it continued to improve until it became the most popular blogging tool. Later, it continued to improve as a CMS (Content Management System) and now has a reputation for being the most popular CMS for over five years. These days, everyone sees WordPress as a CMS rather than just a blogging tool.

Now the question is, where will it go next?

Recent versions of WordPress have included popular web development libraries such as Backbone.js and Underscore.js and developers are building different types of applications with WordPress. Also, the most recent introduction of the REST API is a major indication that WordPress is moving towards the direction of building web applications. The combination of the REST API and modern JavaScript frameworks will enable developers to build complex web applications with WordPress.

Before we consider the application development aspects of WordPress, it's ideal to figure out the reasons for it being such a popular CMS. The following are some of the reasons behind the success of WordPress as a CMS:

The plugin-based architecture for adding independent features and the existence of over 40,000 open source plugins

The ability to create unlimited free websites at www.wordpress.com and use the basic WordPress features

A super simple and easy-to-access administration interface

A fast learning curve and comprehensive documentation for beginners

A rapid development process involving themes and plugins

An active development community with awesome support

The flexibility in building websites with its themes, plugins, widgets, and hooks

The availability of large premium theme and plugin marketplaces for developers to sell advanced plugin/themes and users to build advanced sites with those premium plugins/themes without needing a developer

These reasons prove why WordPress is the top CMS for website development. However, experienced developers who work with full stack web applications don't believe that WordPress has a future in web application development. While it's up for debate, we'll see what WordPress has to offer for web development.

Once you complete reading this book, you will be able to decide whether WordPress has a future in web applications. I have been working with full stack frameworks for several years, and I certainly believe in the future of WordPress for web development.

WordPress as a web application framework

In practice, the decision to choose a development framework depends on the complexity of your application. Developers will tend to go for frameworks in most scenarios. It's important to figure out why we go with frameworks for web development. Here's a list of possible reasons why frameworks become a priority in web application development:

Frameworks provide stable foundations for building custom functionalities

Usually, stable frameworks have a large development community with an active support

They have built-in features to address the common aspects of application development, such as routing, language support, form validation, user management, and more

They have a large amount of utility functions to address repetitive tasks

Full stack development frameworks such as Zend, CodeIgniter, and CakePHP adhere to the points mentioned in the preceding section, which in turn becomes the framework of choice for most developers. However, we have to keep in mind that WordPress is an application where we build applications on top of existing features. On the other hand, traditional frameworks are foundations used for building applications such as WordPress. Now, let's take a look at how WordPress fits into the boots of the web application framework.

The MVC versus event-driven architecture

A vast majority of web development frameworks are built to work with MVC architecture, where an application is separated into independent layers called models, views, and controllers. In MVC, we have a clear understanding of what goes where and when each of the layers will be integrated in the process.

So, the first thing most developers will look at is the availability of MVC in WordPress. Unfortunately, WordPress is not built on top of the MVC architecture. This is one of the main reasons why developers refuse to choose it as a development framework. Even though it is not MVC, we can create custom execution processes to make it work like an MVC application. Also, we can find frameworks such as WP MVC, which can be used to take advantage of both WordPress's native functionality and its vast plugin library and all of the many advantages of an MVC framework. Unlike other frameworks, it won't have the full capabilities of MVC. However, the unavailability of MVC architecture doesn't mean that we cannot develop quality applications with WordPress. There are many other ways to separate concerns in WordPress applications.

On the other hand WordPress, relies on a procedural event-driven architecture with its action hooks and filters system. Once a user makes a request, these actions will get executed in a certain order to provide the response to the user. You can find the complete execution procedure at http://codex.wordpress.org/Plugin_API/Action_Reference.

In the event-driven architecture, both model and controller code gets scattered throughout the theme and plugin files. In the upcoming chapters, we will look at how we can separate these concerns with the event-driven architecture, in order to develop maintainable applications.

Simplifying development with built-in features

As we discussed in the previous section, the quality of a framework depends on its core features. The better the quality of the core, the better it will be for developing quality and maintainable applications. It's surprising to see the availability of a number of WordPress features directly related to web development, even though it is meant to create websites.

Let's get a brief introduction to the WordPress core features to see how they fit into web application development.

User management

Built-in user management features are quite advanced in order to cater to the most common requirements of any web application. Its user roles and capability handling make it much easier to control the access to specific areas of your application. We can separate users into multiple levels using roles and then use capabilities to define the permitted functionality for each user level. Most full stack frameworks don't have built-in user management features, and hence this can be considered as an advantage of using WordPress.

Media management

File uploading and managing is a common and time consuming task in web applications. Media uploader, which comes built-in with WordPress, can be effectively used to automate the file-related tasks without writing much source code. A super-simple interface makes it so easy for application users to handle file-related tasks.

Template management

WordPress offers a simple template management system for its themes. It is not as complex or fully featured as a typical template engine. However, it offers a wide range of capabilities from a CMS development perspective, which we can extend to suit web applications.

Database management

In most scenarios, we will be using the existing database table