Choosing the Right Architecture for Your Laravel Project

Selecting the appropriate architecture is crucial for the success of any software project. The choice depends on various factors, including the project's scope, the number of developers, dependability requirements, and whether it’s a fast-moving project for an imminent launch or a large-scale enterprise application. In this article, I want to explore when to use Domain-Driven Design (DDD), Test-Driven Development (TDD), the default Laravel structure, and modular architecture.

Default Laravel Structure

The default Laravel structure is ideal for small to medium projects that require quick development and deployment. It is well-suited for small to medium teams where the minimal communication overhead is beneficial. This structure has been polished over the years and thrives in fast-moving projects where rapid prototyping or tight deadlines are crucial. Additionally, with tools like ESLint, Prettier, PHPCSFixer, and static analysis ensures code consistency and quality, while CI/CD pipelines can help automate testing and deployment processes.

Domain-Driven Design (DDD)

Domain-Driven Design (DDD) is best for projects with complex business logic and large-scale applications that require a detailed model of business domains. Suitable for mid to large teams, DDD focuses on creating a shared understanding of the business domain within the development team, enabling them to manage complexity through well-defined domain boundaries.

Modular Architecture

Modular architecture is ideal for large-scale applications expected to grow in size and complexity. It suits large teams divided into sub-teams, each responsible for different modules. This architecture is particularly useful for projects adopting a micro-services approach, where different modules might be developed, deployed, and scaled independently.

Test-Driven Development (TDD)

Test-Driven Development (TDD) integrates testing into the development workflow, ensuring tests are written before features are implemented. It is particularly beneficial for long-term projects that require ongoing maintenance and high-resilience.

Take Just What You Need

In the ever-evolving landscape of software development, technologies are constantly changing, new and better architectures quickly gain attention, and improvements are continually rolling out to address existing flaws. In the middle of all this change, I find it essential to focus on the core principles that build up the different architectures without feeling gatekept by rigid structures, complex principles, and daunting tasks, especially for newcomers. By adopting fundamental practices and concepts, you can significantly improve your projects without falling in the rebuild from scratch rabbit hole.

Learning from DDD

Domain-Driven Design (DDD) offers a wide range of practices that not only help to manage complex business logic but also significantly bridge the inherent gaps in PHP’s type system. You don’t need to fully buy into DDD to leverage its benefits. By integrating certain key elements, you can enhance PHP’s type system and elevate the overall quality of your codebase.

Domains and Namespaces

Organizing your code around domains and namespaces not only makes it more logical but also aligns your codebase with real-world business contexts.

• Clarity Through Consistency: Segmenting your code into well-defined domains and namespaces gives it a clean, logical structure. For example, if the business refers to "Shipments", don´t name your classes "Orders", structuring your code to reflect the business terms makes your application easier to navigate and understand.
• Improved Communication: Reflecting business terminology in your code simplifies discussions with non-developers and stakeholders, leading to better communication and fewer misunderstandings.

Value Objects

Value Objects encapsulate data and add semantic meaning, moving away from basic types like strings and integers.

• Enhanced Type Safety: Instead of using a plain integer or float for representing percentages, encapsulate it in a "Percent" Value Object. This ensures that operations involving percentages are type-safe and consistently validated and formatted.
• Clear Semantics: Value Objects like Money not only provide type safety but also make your intentions clear.

Data Transfer Objects (DTOs)

DTOs are critical in DDD for transferring data between the different layers of your application. However, their utility extends beyond that.

• Structured Data Handling: Using DTOs ensures well-defined data structures, making your code more predictable and easier to debug. This addresses the shortcomings of Laravel’s magic attribute access, where doc-block typing isn’t always enough.
• Type Safety: DTOs help close the typing gap, ensuring that data passed between layers is type-safe and documented, improving readability and thus maintainability.

Custom Query Builders

When it comes to data access, Laravel’s custom query builders often provide a more streamlined and effective solution than repositories.

• Efficient Data Access: Custom query builders in Laravel allow you to encapsulate complex queries, keeping your data access code clean and manageable without the overhead of additional abstraction layers.

Actions

Actions are focused, self-contained classes that handle specific tasks, effectively combining the roles traditionally played by repositories and service classes.

• Single Responsibility Principle: Each action performs one specific task, such as creating an order or sending a notification. This adherence to single responsibility makes your code easier to read, test, and reuse.
• Self-Contained Logic: Actions can encapsulate all necessary steps to complete a task, from validation to execution. This modularity makes them highly reusable and decoupled from the rest of the application.

ViewModels

ViewModels act as intermediaries between your logic and the presentation layer, providing strong typing all the way through to the frontend.

• Type-Safe Frontend Integration: ViewModels ensure that only the required data is sent to the frontend, and it’s strongly typed. Not only with blade, tools like Spatie’s typescript-transformer can be used to generate TypeScript definitions, making it seamless to integrate with Inertia.js and TypeScript.

Wrapping DDD

Incorporating elements from DDD can profoundly enhance your Laravel projects. By integrating Value Objects, DTOs, custom query builders, actions, and ViewModels, you can create a codebase that is more robust, maintainable, and aligned with real-world business needs. The beauty of DDD-inspired practices is that you can adopt these elements individually without fully committing to a complete DDD architecture, allowing for incremental improvements and a smoother transition toward a more structured and logical design.

Learnings from TDD

Incorporating TDD into your development process fundamentally boosts the reliability and maintainability of your code. However, it can be overwhelming, especially when you’re just starting out. Instead of stressing over writing tests first, focus on designing your code with future testing in mind. Think about how you can make the task of writing tests easier and more enjoyable down the road.

Mocking

Mocking allows you to simulate the behavior of complex dependencies, making it easier to test various scenarios without relying on actual implementations. Think about the data you are consuming and manipulating in your application, and how you are accessing it while working on the implementation. Ask yourself how you will mock these dependencies in feature tests and how you can make it easier by isolating your dependencies so you can test cases with finely-tuned conditions.

Imagine you need to integrate with a complex API; it might be tempting to wrap everything into a service class. However, this approach can make it difficult to test different scenarios and replicate various potential responses from the API without actually reaching it. In this case, you could separate the API business logic and API client communication.

Isolation

When you anticipate complex logic, consider how you can isolate it to make testing more straightforward. Isolation ensures that each unit of your code can be tested independently of the rest of the application.

Example:

// Isolating complex logic into a service class
class TaxCalculator
{
    public function calculateTax($amount)
    {
        // Complex calculation logic
        return $amount * 0.15;
    }
}

// In your test
$calculator = new TaxCalculator();
$this->assertEquals(15, $calculator->calculateTax(100));

By isolating the tax calculation logic in its own service, you can test the calculation independently, ensuring its correctness without interference from other parts of the application.

Design with Testing in Mind

To ensure robust feature testing, it's crucial to design your features in a way that their logic can be easily targeted. Clearly define and isolate the building blocks of your features, keeping them slim and focused. This approach facilitates feature tests, allowing both the entire scenario and its individual components to be tested. This ensures resilience and enables quick identification of any problematic changes.

A practical example of making your application test-ready is the use of action classes. This ensures that individual flows can be tested both in isolation and as part of the overall system.

Wrapping TDD

By incorporating TDD, you envision the test cases and their expected outcomes first. This disciplined approach helps clarify requirements and ensures the code meets those requirements. However, it can be overwhelming, especially when you’re just starting out. Instead of worrying about writing tests first, focus on thinking about how you will test your code later and how you can make the task of writing tests easier and more enjoyable down the road. Consider how to design your code so that it is easy to mock dependencies, test components in isolation, and split your code into manageable chunks. This mindset will naturally ease you into TDD without the initial stress, setting you up for success as your project evolves.

Conclusions

Selecting the right architecture for your Laravel project is crucial, and it depends on various factors, including project complexity, team size, and long-term maintenance needs. But keep in mind that there is no single perfect architecture. The default Laravel structure is great for small, fast-moving projects where simplicity and speed are essential. However, for complex, large-scale applications, Domain-Driven Design (DDD) provides a way to manage intricate business logic with a structured and logical codebase. Test-Driven Development (TDD) enhances code reliability and maintainability, making it ideal for projects requiring high quality and long-term support. Modular architecture allows for scalable and independently deployable components, which is essential for large teams and evolving projects.

Adopting practices from DDD, such as Domains and Namespaces, Value Objects, Data Transfer Objects (DTOs), Actions, and ViewModels, can significantly improve your Laravel projects. These elements not only help to create a more organized and maintainable codebase but also bridge the gaps in PHP’s type system. By implementing Value Objects, you enforce type safety and ensure consistent data handling. DTOs provide structured and type-safe data transfer, addressing the limitations of Laravel's dynamic properties. Actions encapsulate business logic within single-responsibility classes, enhancing modularity and reusability, while ViewModels ensure strong typing all the way to the frontend, improving the interaction between backend and frontend components.

Incorporating TDD into your workflow doesn’t mean you have to write all the tests first, right from the beginning. Instead, start by thinking about how you will test your code as you design and implement it. Think about how you will mock or test later, and focus on coherent code splitting and isolation to make testing intuitive. Gradually expand your test coverage as you grow more comfortable with TDD, focusing on the core of your application.

By understanding the strengths and weaknesses of each architectural approach and integrating these key best practices, you can make informed decisions that align with your project goals and team dynamics. Whether you’re working on a quick MVP or a large-scale enterprise application, these strategies will help you develop high-quality, maintainable, and scalable Laravel applications.