PHP Master | Practical Code Refactoring, Part 3 - Extensibility

Key Points

• Scalable code follows a reusable, clear logic and well-known pattern, and modular code is often highly scalable. Monomer code may be more efficient but is less scalable, so it may be beneficial to strike a balance between the two.
• Logical scalability involves using the most logical and common language features for work. For complex solutions, it is recommended to follow standard design patterns as they are easy to understand and take into account future developments.
• Modular design involves dividing applications into modules, which makes development, expansion and maintenance easier. Each module should combine relevant features and functions. Modules should be self-contained as much as possible and minimize dependencies to simplify debugging and deployment.
• Decoupling and encapsulation involves separating functions, methods, and classes to enhance the reusability and scalability of the code. Reducing dependencies between modules and components can improve availability and scalability as long as it does not overcomplicate the code.

In the second part of the series, I shared some questions about code refactoring to improve readability. In this section, we will discuss another aspect: scalability. We will take the same practical question/discussion approach as in the previous section so that you can enter the new refactoring world as soon as possible. Extensible code refers to snippets of code that follow reusable, logically clear and well-known patterns, whether it is a standard design pattern or a normal logical flow. Modular code is often very scalable, while monolithic code is often not scalable, but monolithic code may be more efficient. Therefore, to solve this problem, some practices allow development in a modular way and monolithic. deploy so that we can achieve the best of both worlds. The main aspects of extensible code we will discuss include: logical scalability (normal logical flow and design patterns), modular design, and decoupling and encapsulation.

Logical scalability

1. Does most code blocks follow normal logical flow? When dealing with small logic problems, make sure you are using the correct structure (if, for, foreach, while, etc.). By "correct structure" I mean you should use the most logical and common language features for this work. For example, iterating through simple arrays should use foreach; this is a common normal process, while using for loops for such simple iterations is not a normal process in languages ​​such as PHP. For such a simple task, using while is even more unfamiliar. You may have your reasons, in this case, recall the previous section about documenting any custom practices, so that's fine.
2. Does complex solutions follow standard design patterns? When I first started using PHP, I didn’t know much about design patterns. Now I find that using design patterns is a must for large projects because they are easy to understand and take into account future developments. A common complex problem that you should solve using a well-defined standard pattern is to create various instances of a certain class. But why and when to use the factory design pattern? This may be controversial, but the general guidelines are as follows: This pattern may apply if you have different implementations of the same interface and you need to create an implementation object dynamically. Another case might be when many dynamic objects of the same class are generated but the number is only known at runtime. For example, modern GUI-intensive web applications may need to create dynamic form input lines for database records. There are countless examples of when design patterns will be useful.

Modular design

1. Does the code structure follow modular design? Modular design means you divide your application into modules. Larger applications made up of smaller applications are easier to develop and easier to scale and maintain. Each module should collect a set of relevant features and functions and combine them in one entity. Core functions and application entry points can also be considered modules. You can then add future features by adding new modules. Some people refer to modules used in this way as plugins. However, no matter which design and structure you choose for your application, you need to ensure how modules/plugins load and uninstall them, their basic structure, etc., and consider these issues before developing core modules. Whenever you see a code group in a module acts as its single child entity and is used by that top-level module with minimal parameters, why not split it into a new module? Usually, when I have a child entity split into multiple classes to perform some auxiliary tasks, I don't hesitate to move it into a new module. Utility modules are a clever solution to orphaned code in well-designed modular applications. Whenever I have some orphan code, I move it into a utility module that handles code snippets and small tasks. This module is usually composed of orphaned functions and subclasses. Whenever these tasks are big enough, I start moving them into its own separate module, which is a continuous refactoring process.
2. Is the module least dependency? Modules should be self-contained as much as possible. Soft module dependencies are natural and good, for example, the "inventory" module depends on the "accounting" module to obtain a homogeneous e-commerce system, but many hard dependencies are bad. They make debugging and deployment more difficult. To ensure fewer inter-module dependencies, you must iterate over your code base from time to time to see if there are any hard dependencies between modules. Clear them if you can, and if you can, you should merge the two modules into one with a more common name. For example, in an e-commerce application, you might have a "Project" module and an "Inventory" management module, and classes in inventory use a lot of classes in the project and vice versa. I would merge the two and rename the module to "Inventory", which contains a submodule for handling the project.

Decoupling and packaging

1. Are functions, methods and classes quite decoupled? Adding a paging feature to display results from a database is a very common task. In fact, during my early PHP development career, I wrote some code to paginate the results; the initial code was procedural, containing very specific functions for handling databases and results. I then decided to decouple the paging algorithm with each component I use it with using it. Whenever you find yourself repeating logic or code, you may need to do some decoupling to enhance the reusability and scalability of your code.
2. Are modules and components quite decoupled? You are decoupling the right way while keeping the dependencies to a minimum. There is no 100% decoupling between any two related things; coupling is natural, so you should always decouple, but not too much to avoid eventually making your code more complicated. As a guideline, decouple until the modules and components of your code base are able to communicate with each other without much repetitive commonality. Remember that whenever complexity does not increase, reducing dependency is proportional to availability and scalability. When complexity begins to increase, the relationship begins to be inversely proportional.

Summary

In this section, we discuss refactoring the code for scalability, focusing on three main aspects: logical scalability, modular design, and decoupling and encapsulation. Hopefully now you have started to better understand how to develop and maintain better applications. In the last section, we will discuss how to refactor for efficiency without compromising readability and scalability. Pictures from Fotolia

Frequently Asked Questions about Code Refactoring (FAQ)

What is the importance of PHP code refactoring?

Code refactoring is a key process in PHP development. It involves reorganizing existing code without changing its external behavior to improve the non-functional properties of the software. Refactoring makes the code easier to read, maintain, and extend. It helps identify and correct hidden errors of software and improves its performance. It also makes it easier for other developers to understand and process code, thereby increasing the overall productivity of the development team.

How to improve the readability of PHP code?

Improving the readability of PHP code involves a variety of practices. First, use meaningful names for variables, functions, and classes. Second, keep functions and classes small and focus on a single task. Third, use comments to explain the purpose of complex code parts, but avoid unnecessary comments to mess up the code. Finally, follow PHP's standard coding conventions, such as correct indentation, use of spaces, and consistent naming conventions.

What is scalability in the context of PHP code?

Scalability in PHP code refers to the ability of the code to extend or modify new features without affecting existing system performance or functionality. This is achieved by writing modular code, using object-oriented programming principles, and following SOLID principles. Extensible code is easier to maintain, upgrade and expand, making it an ideal property in software development.

How to make my PHP code more scalable?

Making your PHP code more scalable involves a variety of practices. First, write modular code and organize it into small independent units (modules) that can be modified or expanded independently. Second, use object-oriented programming principles such as encapsulation, inheritance, and polymorphism to create reusable and extensible code. Third, follow the SOLID principles, which provide guidance for designing software that is easy to maintain, understand, and extend.

What are the common challenges in code refactoring?

Code refactoring can be challenging for a variety of reasons. First, it requires a deep understanding of the functions of the code and software. Second, it can be very time consuming, especially for large code bases. Third, if it is not operated properly, it may introduce new errors. Finally, it may require changes to the testing and deployment process, which can cause interference.

How to overcome the challenges in code refactoring?

Overcoming the challenges in code refactoring involves multiple strategies. First, before starting the refactoring process, get a deeper understanding of the functions of the code and software. Second, use automatic refactoring tools to save time and reduce the risk of introducing new errors. Third, incrementally refactor the code, starting with the small manageable part of the code. Finally, make sure you have a strong testing process to catch any errors introduced during the refactoring process.

What are the best practices for code refactoring?

Best practices for code refactoring include understanding the code and its functions before starting the refactoring process, incrementally refactoring the code, using automatic refactoring tools, and having a powerful testing process. In addition, it is also important to communicate with your team about the refactoring process and its impact on the project.

How to make sure my refactoring code is free of errors?

Ensuring that refactoring the code is free of errors requires a powerful testing process. Use unit tests to test individual components of your code, use integration tests to test how these components interact, and use system tests to test the entire software. Additionally, automated testing tools are used to capture any errors that may be introduced during the refactoring process.

How to measure whether the code refactoring work is successful?

There are many ways to measure whether the code refactoring work is successful. First, the refactored code should be easier to read, maintain and extend. Secondly, the performance of the software should be improved. Third, the number of errors in the code should be reduced. Finally, the development team should be easier to handle the code.

What are some good resources to learn more about code refactoring?

There are many good resources to learn more about code refactoring. Some popular books on the topic include Martin Fowler’s “Refactoring: Improving the Design of Existing Code” and Michael Feathers’ “Efficient Use of Legacy Code.” In addition, there are many online tutorials, courses and articles about code refactoring on platforms such as Coursera, Udemy, and Medium.

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