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 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. 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.