Why do you have to build a module?
A custom module is essentially built to extend the core functionality of Drupal; which by itself comes with built-in set of core modules. However, the true nature of Drupal mainly comes from hundreds and thousands of custom modules developed by the dedicated community.
Regardless of how your experience has been with the previous versions of Drupal, module development in Drupal 8 has its own set of challenges. To give you a fair idea, there are some differences between Drupal 7 and Drupal 8, the key ones being that Drupal 8 requires the latest version of the php5 to run and it uses Symphony, a php framework that relies on Object Oriented Programming. Also, there are changes in the way a module is built and there are certain best practices to keep up with the community standards. Let us talk a bit more about this, and some of these practices for Drupal 8 module development.
One of the major things to be aware of, in Drupal 8 module development is the file structure which is quite different from the one in Drupal 7. In Drupal 8, the custom modules built are stored in the /modules directory, unlike in Drupal 7 where this directory was reserved for the core modules. The core modules of Drupal 8 now go into the /core directory.
Next up, to let Drupal know that your custom module exists, you need to create a .info.yml file which provides the meta data. This process is similar to the one used for Drupal 7.
name - This key is to provide a name for your custom module.
type - This key defines the type of the extension (module/theme/profile).
description - This key provides the detailed description about the custom module (displayed on the module list page).
package - This key specifies the package in which the module should be included.
version - Specifies the version of the module.
If your file is something like 'blogexmple_module.info.yml', the syntax will be as follows.
name - Blogexmple Module
type - module
description - A simple demo module
package - Custom
version - 1.0
core - 8.x
Use of Configuration before code
Having to rewrite the code every time you change it is not something which you would want to do. Instead of hard coding a class into a theme, set the values in the configuration and apply it with the code. This ensures easy and faster ways to code and also results in high quality modules. With reusable codes being the norm in writing quality software, configurations in the code ensure advanced functionality and and "easy to modify" features.
Use What Drupal Offers
Once you have built your module, you should know that Drupal comes with various built-in admin functionalities to store and display module data and settings. The module settings page can be defined with hook menu . This hook enables modules to register paths in order to define how URL requests are handled. With the drupal_get_form page callback usage, all you have to do in the callback function is define and return the settings that are to be stored.
Too Many Cooks Spoil The Broth
Having worked on large scale Drupal sites for a long time, Drupal developers would have learn that hundreds of modules can work their magic together to produce an effective large-scale project. But when working on enterprise Drupal websites, it is important to note that avoiding a single poor module has greater effects than avoiding 30 well built Drupal modules (in an attempt to use lesser modules). This too many modules advice leads programmers to favor programming their own modules over reusing modules. The higher the number of custom modules you write for a project, the more work it takes to maintain and modify your Drupal site later. Instead, consider publishing your modules on Github. This allows you to avoid usage of a large collection of custom modules and instead encourage you to create reusable code that has the required configuration.
Environment & Coding Standards
Development environment is an important influence as it ensures that a Drupal project runs without any hassle. Drupal development companies ensure that the entire team works in an exactly same development environment for an efficient work-flow.
While working in such an environment, one of the biggest issues to handle is to make sure that the code is clean and maintainable. Drupal developers need to make sure that their code is readable and makes sense to everyone they are working with. And this doesn't apply only to the team members or to anyone from your organization, but also to the larger Drupal community itself. With community involvement being an essential part of Drupal development and a key aspect in distributed teams working together efficiently, following the coding standards helps in achieving a project's goals and objectives.
Being an open source platform, in a short span of time, Drupal has made tremendous impact on businesses. Many top organizations like PayPal, Tesla and NASA have leveraged the power of Drupal with their modular framework. Backed by a strong community which is constantly improving the platform and extending its core functionalities with new and exciting modules, Drupal has gained a competitive edge. As an experienced Drupal development company or a Drupal developer, you are bound to face some bumps when you get your hands on building those custom modules, and following the above discussed best practices will help you steady the ship.