5 Essential Topics for Beginner OutSystems Developers

OutSystems is a powerful low-code platform that enables developers to rapidly build enterprise-grade applications. Its visual development environment simplifies coding; however, adhering to best practices is crucial to ensure that the applications are not only functional but also scalable, maintainable, and performant. This guide outlines key practices that developers and tech leads should follow when working with OutSystems.

Application Architecture and Design

1. Modular Design

Modular design is a crucial practice in OutSystems development. It involves breaking down an application into smaller, manageable, and reusable modules. Here’s how to approach it:

- Organizing Modules by Functionality: Start by identifying distinct functionalities within the application, such as user management, billing, and reporting. Each of these can be developed as separate modules. By isolating these functions, you reduce the complexity of each module, making it easier to develop, test, and maintain.

- Encapsulation: Each module should encapsulate its logic and data, exposing only what is necessary through well-defined interfaces. This promotes reusability across different parts of the application or even across different projects.

- Module Dependencies: Be mindful of dependencies between modules. Aim to minimize tightly coupled dependencies as they can complicate future changes and lead to a tangled architecture. Use the OutSystems module dependency management tools to keep track of how modules are connected.

- Common vs. Core Modules: Identify modules that will serve as foundational layers, often called core or common modules. These might include shared services like authentication or utilities that other modules will depend on. Ensuring these core modules are robust and stable is key to a resilient architecture.

2. Adopt a Service-Oriented Approach

A service-oriented approach in OutSystems focuses on building applications where services are modular, reusable, and easily integrable. This involves exposing core functionalities as services that other modules or external systems can consume. Here’s how to effectively implement it:

- Designing Services: Start by identifying functionalities that can be abstracted into services. These could include business processes, data access layers, or utility functions like logging or error handling. Design these services to be reusable across different applications or modules.

- Exposing Services: OutSystems makes it easy to expose services through REST or SOAP APIs. REST is generally preferred due to its simplicity, performance benefits, and broad compatibility. Ensure that services are well documented with clear input and output specifications.

- Service Composition: In a service-oriented architecture, you can create composite services that combine multiple lower-level services. This allows you to build complex functionalities from simple, well-tested building blocks, improving both reliability and scalability.

- Versioning Services: When exposing services, consider implementing versioning. This allows you to make improvements or changes to a service without breaking existing consumers. A proper versioning strategy is crucial for maintaining backward compatibility.

- Security and Authentication: Secure your services using OutSystems' built-in mechanisms like OAuth 2.0, ensuring that only authorized applications and users can access them. Service-level security measures should be part of the design from the outset, especially for services that handle sensitive data.

Coding Practices

3. Naming Conventions

Naming conventions are fundamental to maintaining a clean, understandable, and navigable codebase in OutSystems. They help developers quickly understand the purpose and context of different elements within the application.

- Consistent Naming: Consistency in naming is key to ensuring that the codebase is easy to read and maintain. Every entity, attribute, action, and variable should follow a predefined naming convention that reflects its purpose. For example:

- Entities: Use singular nouns that accurately describe the data being represented (e.g., `Customer`, `Order`, `Invoice`).

- Attributes: Attribute names should be descriptive and specific, using camelCase or PascalCase depending on your team’s standards (e.g., `CustomerName`, `OrderDate`).

- Actions: Name actions in a way that clearly states what they do, typically starting with a verb (e.g., `CreateOrder`, `UpdateCustomerDetails`).

- Variables: Variables should have meaningful names that reflect their use or content, avoiding generic names like `temp` or `data`.

- Prefixing: Prefixing is a useful technique to categorize different types of objects, making it easier to identify their role within the application. For example:

- `UI_` Prefix for User Interface Elements: This helps in quickly distinguishing UI components like screens and forms from other logic or data entities (e.g., `UI_LoginScreen`, `UI_CustomerForm`).

- `API_` Prefix for Exposed Services: Services that are exposed to other systems should be identified, which helps in managing integrations and maintaining API versions (e.g., `API_GetCustomerDetails`, `API_UpdateOrderStatus`).

- `DB_` Prefix for Database-Related Components: This prefix can be used for components directly related to database operations, such as stored procedures or queries (e.g., `DB_FetchCustomerOrders`).

4. Code Reusability

Code reusability is a cornerstone of efficient development in OutSystems, enabling faster development, reducing redundancy, and ensuring consistency across applications.

- Create Reusable Components: Identify common functionalities that can be abstracted into reusable components. These could be UI elements like buttons, forms, or data grids, as well as logic components like validation routines, data fetching methods, or business rules. For example:

- UI Components: Create a standard button component that can be used across multiple screens, ensuring that any change to the button’s design or behaviour is reflected everywhere it’s used.

- Business Logic: Develop shared actions or services for common business logic, such as calculating taxes or applying discounts. This avoids duplicating code across different modules or applications.

- Use Built-In Patterns: OutSystems provides a range of built-in patterns and templates that are optimized for performance and align with best practices. Leveraging these patterns can significantly speed up development and ensure that your application follows established design principles. Examples include:

- List and Detail Patterns: Use the list and detail patterns for creating screens that display a list of items and a detailed view for each item.

- Master-Detail Patterns: For scenarios where a parent entity has a one-to-many relationship with child entities, use the master-detail pattern to manage data display and interactions efficiently.

- Exception Handling Patterns: Implement standardized exception handling patterns provided by OutSystems to manage errors consistently across your application.

5. Error Handling

Robust error handling is essential for creating reliable and user-friendly applications. Properly managing errors not only improves the user experience but also aids in the maintenance and debugging of the application.

- Centralized Error Logging: Implement a centralized mechanism for capturing and logging errors. This approach involves error-handling services:

- Create a Global Error Handling Service: Develop a service that can be invoked whenever an error occurs. This service should log the error details, including the context in which it occurred, to a centralized logging system.

- Logging Levels: Implement different levels of logging (e.g., info, warning, error) to capture varying degrees of issues, from minor anomalies to critical failures.

- Monitoring Tools: Use OutSystems' built-in monitoring tools or integrate with external logging services like Loggly or Splunk to keep track of errors in real-time and analyze them for patterns or recurring issues.

- Graceful Degradation: Ensure that your application can handle failures gracefully without crashing or leaving the user in an unclear state. Key strategies include:

- User-Friendly Error Messages: Instead of displaying technical error details to users, provide clear, friendly messages that guide them on what to do next. For example, if a data retrieval fails, you might display a message like, "We're having trouble loading your data. Please try again later."

- Fallback Mechanisms: Implement fallback mechanisms where possible. For example, if an external API call fails, the application could use cached data or provide an alternative function to maintain some level of service.

- Error Recovery Options: Where appropriate, give users the option to retry operations or navigate to other parts of the application, rather than forcing them to restart or exit.

Conclusion

Developing applications with OutSystems provides an excellent balance between rapid development and scalability, allowing organizations to bring solutions to market quickly. However, adherence to best practices is essential to truly harness the power of this low-code platform and create applications that stand the test of time.

Adopting a modular design ensures that your applications are scalable, maintainable, and adaptable to future requirements. This approach promotes the reuse of components, reduces complexity, and simplifies maintenance.

Efficient coding practices, such as consistent naming conventions, maximizing code reusability, and implementing robust error handling, further enhance the quality and maintainability of your applications. These practices not only streamline the development process but also make it easier for teams to collaborate and ensure that code is easy to understand and modify.

Incorporating these best practices into your OutSystems development process not only results in functional applications but also in solutions that are resilient and capable of evolving alongside your business needs. By investing in quality from the outset, you position your applications for long-term success, making them valuable assets in your organization’s digital transformation journey.