Apps REST Adapters

The REST project is a specialized module within Applications Adapters. It focuses on creating and managing primary adapters that expose Core workflows as RESTful endpoints for standalone environments and FaaS platforms. Its purpose is to handle all aspects of communication between the application logic and the infrastructure or service framework, ensuring that the Core remains decoupled and reusable.

Project structure

Project Structure

Purpose of the REST Project

  1. Enable RESTful Communication:
    The REST project translates Core workflows and entities into REST API operations, making them accessible through standard HTTP methods like GET, POST, PUT, and DELETE.

  2. Adaptation for FaaS Environments:
    With the rise of serverless computing, REST ensures Core modules integrate seamlessly with FaaS platforms by designing lightweight, stateless adapters for event-driven interactions.

  3. Maintain Core Independence:
    The REST project guarantees that Core logic remains reusable and independent, ensuring REST-specific concerns do not pollute shared workflows or entities.

  4. Support for Standalone Systems:
    REST adapters are also suited for standalone, single-service deployments, enabling small applications to leverage the power of Core workflows in isolated environments.

Key Responsibilities of the REST Project

Primary Adapter Design

The primary focus of REST is to create adapters that transform Core workflows into RESTful endpoints:

  • Expose use cases such as “Create Order”, “Fetch Shipment Status”, or “Calculate Invoice Total” via API routes.
  • Map HTTP methods to Core use case interactors (e.g., POST /orders → CreateOrderInteractor).
  • Handle input and output validation, ensuring request payloads are properly transformed into Core-compatible data models.

Integration with FaaS Platforms

  • Build lightweight REST adapters that work with Function-as-a-Service (FaaS) platforms like AWS Lambda, Google Cloud Functions, or Azure Functions.
  • Automatically convert RESTful HTTP requests into events handled by Core logic, maintaining stateless communication.

Middleware and Framework Adaptation

  • Provide application-specific middleware for authentication, authorization, and logging.
  • Abstract REST implementation details to support frameworks like Spring Boot, Express.js, or Flask without compromising Core logic.

Output Standardization

  • Customize and standardize response formats (e.g., JSON or XML) for consistent communication with external clients and systems.

REST for FaaS Platforms

REST in serverless environments introduces unique challenges, such as stateless execution, ephemeral storage, and event-driven needs. The REST project ensures these challenges are met by:

  • Designing adapters that convert RESTful requests into event payloads consumed by FaaS platforms.
  • Supporting cold starts by keeping adapter layers lightweight and efficient.
  • Managing API Gateway integrations for seamless request routing and scaling.