In this article written by Rakhitha Ratanayake, author of the book Wordpress Web Application Development - Third Edition you will learn that 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 hasalready got dozens of built-in features, which can be easily adapted to web application development using slight modifications. Since you are already reading this article, you have to be someone who is really excited to see how WordPress fits into web application development. Throughout this article, we will learn how we can inject the best practices of web development into WordPress framework to build web applications in rapid process.Basically, this article will be important for developers from two different perspectives. On 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 article, 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

(For more resources related to this topic, see here.)

In order to work with this article, you should be familiar with WordPress themes, plugins, and its overall process. Developers who are experienced in PHP frameworks can work with this article while using the reference sources to learn WordPress. By the end of this article, 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 continued to improve until it became the most popular blogging tool. Later, it continued to improve as a CMS and now has a reputation for being the most popular CMS for over 5 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 REST API is a major indication that WordPress is moving towards the direction of building web applications. The combination of 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:

Plugin-based architecture for adding independent features and the
existence of over 40,000 open source plugins
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
Flexibility in building websites with its themes, plugins, widgets, and hooks
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 article, 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 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 built 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 web application framework.

The MVC versus event-driven architecture

A vast majority of web development frameworks are built to work with the Model-View-Controller(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 process to make it work like a 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 a 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, unavailability of the MVC architecture doesn't mean that we cannot develop quality applications with WordPress. There are many other ways to separate concerns in WordPress applications.

WordPress on the other hand, 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.

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 number of WordPress features directly related to web development, even though it is meant to create websites.

Let's get a brief introduction about the WordPress core features to see how it fits 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 makes 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 a 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. Also, WordPress offers built-in functions for directly uploading media files without the media uploader. These functions can be used effectively to handle advanced media uploading requirements without spending much time.

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 in CMS development perspective, which we can extend to suit web applications.

Database management

In most scenarios, we will be using the existing database table structure for our application development. WordPress database management functionalities offer a quick and easy way of working with existing tables with its own style of functions. Unlike other frameworks, WordPress provides a built-in database structure, and hence most of the functionalities can be used to directly work with these tables without writing custom SQL queries.

Routing

Comprehensive support for routing is provided through permalinks. WordPress makes it simple to change the default routing and choose your own routing, in order to built search engine friendly URLs.

XML-RPC API

Building an API is essential for allowing third-party access to our application. WordPress provides built-in API for accessing CMS-related functionality through its XML-RPC interface. Also, developers are allowed to create custom API functions through plugins, making it highly flexible for complex applications.

REST API

REST API makes it possible to give third-party access to the application data, similar to XML-RPC API. This API uses easy to understand HTTP requests and JSON format making it easier to communicate with WordPress applications. JavaScript is becoming the modern trend in developing applications. So the availability of JSON in REST API will allow external users to access and manipulate WordPress data within their JavaScript based applications.

Caching

Caching in WordPress can be categorized into two sections called persistent and nonpersistent cache. Nonpersistent caching is provided by WordPress cache object while persistent caching is provided through its Transient API. Caching techniques in WordPress is a simple compared to other frameworks, but it's powerful enough to cater to complex web applications.

Scheduling

As developers, you might have worked with cron jobs for executing certain tasks at specified intervals. WordPress offers same scheduling functionality through built-in functions, similar to a cron job. However, WordPress cron execution is slightly different from normal cron jobs. In WordPress, cron won't be executed unless someone visits the site. Typically, it's used for scheduling future posts. However, it can be extended to cater complex scheduling functionality.

Plugins and widgets

The power of WordPress comes from its plugin mechanism, which allows us to dynamically add or remove functionality without interrupting other parts of the application. Widgets can be considered as a part of the plugin architecture and will be discussed in detail further in this article.

Themes

The design of a WordPress site comes through the theme. This site offers many built-in template files to cater to the default functionality. Themes can be easily extended for custom functionality. Also, the design of the site can be changed instantly by switching compatible theme.

Actions and filters

Actions and filters are part of the WordPress hook system. Actions are events that occur during a request. We can use WordPress actions to execute certain functionalities after a specific event is completed. On the other hand, filters are functions that are used to filter, modify, and return the data. Flexibility is one of the key reasons for the higher popularity of WordPress, compared to other CMS. WordPress has its own way of extending functionality of custom features as well as core features through actions and filters. These actions and filters allow the developers to build advanced applications and plugins, which can be easily extended with minor code changes. As a WordPress developer, it's a must to know the perfect use of these actions and filters in order to build highly flexible systems.

The admin dashboard

WordPress offers a fully featured backend for administrators as well as normal users. These interfaces can be easily customized to adapt to custom applications. All the application-related lists, settings, and data can be handled through the admin section.

The overall collection of features provided by WordPress can be effectively used to match the core functionalities provided by full stack PHP frameworks.

Identifying the components of WordPress

WordPress comes up with a set of prebuilt components, which are intended to provide different features and functionality for an application. A flexible theme and powerful admin features act as the core of WordPress websites, while plugins and widgets extend the core with application-specific features. As a CMS, we all have a pretty good understanding of how these components fit into a WordPress website.

Here our goal is to develop web applications with WordPress, and hence it is important to identify the functionality of these components in the perspective of web applications. So, we will look at each of the following components, how they fit into web applications, and how we can take advantage of them to create flexible applications through a rapid development process:

The role of WordPress themes
The role of admin dashboard
The role of plugins
The role of widgets

The role of WordPress themes

Most of us are used to seeing WordPress as a CMS. In its default view, a theme is a collection of files used to skin your web application layouts. In web applications, it's recommended to separate different components into layers such as models, views, and controllers. WordPress doesn't adhere to the MVC architecture. However, we can easily visualize themes or templates as the presentation layer of WordPress.

In simple terms, views should contain the HTML needed to generate the layout and all the data it needs, should be passed to the views. WordPress is built to create content management systems, and hence, it doesn't focus on separating views from its business logic. Themes contain views, also known as template files, as a mix of both HTML code and PHP logic. As web application developers, we need to alter the behavior of existing themes, in order to limit the logic inside templates and use plugins to parse the necessary model data to views.

Structure of a WordPress page layout

Typically, posts or pages created in WordPress consist of five common sections. Most of these components will be common across all the pages in the website. In web applications, we also separate the common layout content into separate views to be included inside other views. It's important for us to focus on how we can adapt the layout into web application-specific structure. Let's visualize the common layout of WordPress using the following diagram:

wordpress-web-application-framework-img-0

Having looked at the structure, it's obvious that Header, Footer, and the Main Contentarea are mandatory even for web applications. However, the Footerand Commentssection will play a less important role in web applications, compared to web pages. Sidebaris important in web applications, even though it won't be used with the same meaning. It can be quite useful as a dynamic widget area.

Customizing the application layout

Web applications can be categorized as projects and products. A project is something we develop targeting specific requirements of a client. On the other hand, a product is an application created based on the common set of requirements for wide range of users. Therefore, customizations will be required on layouts of your product based on different clients.

WordPress themes make it simple to customize the layout and features using child themes. We can make the necessary modifications in the child theme while keeping the core layout in the parent theme. This will prevent any code duplications in customizing layouts. Also, the ability to switch themes is a powerful feature that eases the layout customization.

The role of the admin dashboard

The administration interface of an application plays one of the most important roles behind the scenes. WordPress offers one of the most powerful and easy-to-access admin areas amongst other competitive frameworks. Most of you should be familiar with using admin area for CMS functionalities. However, we will have to understand how each component in the admin area suits the development of web applications.

The admin dashboard

Dashboard is the location where all the users get redirected, once logged into admin area. Usually, it contains dynamic widget areas with the most important data of your application. Dashboard can play a major role in web applications, compared to blogging or CMS functionality. The dashboard contains a set of default widgets that are mainly focused on main WordPress features such as posts, pages, and comments. In web applications, we can remove the existing widgets related to CMS and add application-specific widgets to create a powerful dashboard. WordPress offers a well-defined API to create a custom admin dashboard widgets and hence we can create a very powerful dashboard using custom widgets for custom requirements in web applications.

Posts and pages

Posts in WordPress are built for creating content such as articles and tutorials. In web applications, posts will be the most important section to create different types of data. Often, we will choose custom post types instead of normal posts for building advanced data creation sections. On the other hand, pages are typically used to provide static content of the site. Usually, we have static pages such as About Us, Contact Us, Services, and so on.

Users

User management is a must use section for any kind of web application. User roles, capabilities and profiles will be managed in this section by the authorized users.

Appearance

Themes and application configurations will be managed in this section. Widgets and theme options will be the important sections related to web applications. Generally, widgets are used in sidebars of WordPress sites to display information such as recent members, comments, posts, and so on. However, in web applications, widgets can play a much bigger role as we can use widgets to split main template into multiple sections. Also, these types of widgetized areas become handy in applications where majority of features are implemented with AJAX.

The theme options panel can be used as the general settings panel of web applications where we define the settings related to templates and generic site-specific configurations.

Settings

This section involves general application settings. Most of the prebuilt items in this section are suited for blogs and websites. We can customize this section to add new configuration areas related to our plugins, used in web application development.

There are some other sections such as links, pages, and comments, which will not be used frequently in complex web application development. The ability to add new sections is one of the key reasons for its flexibility.

The role of plugins

In normal circumstances, WordPress developers use functions that involve application logic scattered across theme files and plugins. Even some of the developers change the core files of WordPress. Altering WordPress core files, third-party theme or plugin files is considered a bad practice since we lose all the modifications on version upgrades and it may break the compatibility of other parts of WordPress. In web applications, we need to be much more organized.

In the Role of WordPress theme section, we discussed the purpose of having a theme for web applications. Plugins will be and should be used to provide the main logic and content of your application. The plugins architecture is a powerful way to add or remove features without affecting the core. Also, we have the ability to separate independent modules into their own plugins, making it easier to maintain. On top of this, plugins have the ability to extend other plugins. Since there are over 40,000 free plugins and large number of premium plugins, sometimes you don't have to develop anything for WordPress applications. You can just use number of plugins and integrate them properly to build advanced applications.

The role of widgets

The official documentation of WordPress refers to widgets as a component that adds content and features to your sidebar. In a typical blogging or CMS user's perspective, it's a completely valid statement. Actually, the widgets offer more in web applications by going beyond the content that populates sidebars. Modern WordPress themes provides wide range of built-in widgets for advanced functionality, making it much more easier to build applications. The following screenshot shows a typical widgetized sidebar of a website:

wordpress-web-application-framework-img-1

We can use dynamic widgetized areas to include complex components as widgets, making it easy to add or remove features without changing source code. The following screenshot shows a sample dynamic widgetized area. We can use the same technique for developing applications with WordPress.

wordpress-web-application-framework-img-2

Throughout these sections, we covered the main components of WordPress and how they fit into the actual web application development. Now, we have a good understanding of the components in order to plan our application developed throughout this article.

A development plan for the forum management application

In this article, our main goal is to learn how we can build full stack web applications using built-in WordPress features. Therefore, I thought of building a complete application, explaining each and every aspect of web development.

We will develop an online forum management system for creating public forums or managing support forum for a specific product or service. This application can be considered as a mini version of a powerful forum system like bbPress. We will be starting the development of this application.

Planning is a crucial task in web development, in which we will save a lot of time and avoid potential risks in the long run. First, we need to get a basic idea about the goal of this application, features and functionalities, and the structure of components to see how it fits into WordPress.

Application goals and target audience

Anyone who are using Internet on day to day basis knows the importance of online discussion boards, also known as forums. These forums allows us to participate in a large community and discuss common matters, either related to a specific subject or a product. The application developed throughout is intended to provide simple and flexible forum management application using a WordPress plugin with the goals of:

Learning to develop a forum application
Learning to use features of various online forums
Learning to manage a forum for your product or service

This application will be targeted towards all the people who have participated in an online forum or used a support system of a product they purchased. I believe that both output of this application and the contents will be ideal for the PHP developers who want to jump into WordPress application development.

Summary

Our main goal was to find how WordPress fits into web application development. We started this articleby identifying the CMS functionalities of WordPress. We explored the features and functionalities of popular full stack frameworks and compared them with the existing functionalities of WordPress.

Then, we looked at the existing components and features of WordPress and how each of those components fit into a real-world web application. We also planned the forum management application requirements and identified the limitations in using WordPress for web applications.

Finally, we converted the default interface into a question-answer interface in a rapid process using existing functionalities, without interrupting the default behavior of WordPress and themes.

By now, you should be able to decide whether to choose WordPress for your web application, visualize how your requirements fits into components of WordPress, and identify and minimize the limitations.