This page details the internal structure and architectural decisions of the BeenThere backend. It follows a layered architecture pattern with clear separation of concerns, making it maintainable, testable, and scalable.

Layered Architecture Overview

The backend is organized in the following primary layers:

flowchart LR

Controller --> Service --> Repository --> Database

Each layer has a specific responsibility:

Layer	Responsibility
Controller	Handles HTTP requests and responses, performs request validation
Service	Contains business logic and transaction management
Repository	Abstracts persistence operations using Spring Data JPA
Model	Defines domain entities and DTOs (Data Transfer Objects)

Project Structure (High-Level)

backend/
├── src/
│   └── main/
│       └── kotlin/
│           └── ghdrope/beenthere/backend/
│               ├── controller/
│               ├── service/
│               ├── repository/
│               ├── model/
│               └── BackendApplication.kt
│
│   └── resources/
│       ├── application.yml
│       ├── application-local.yml
│       └── application-docker.yml
│
├── dev-db-compose.yaml
├── Makefile
├── detekt.yml
└── build.gradle.kts

Package Responsibilities

`controller/`

Exposes REST endpoints via @RestController
Applies validation with @Valid
Uses Spring annotations like @PostMapping, @GetMapping, etc.

`service/`

Central place for business logic
Contains transactional methods via @Transactional
Delegates persistence to the repository layer