GitHub Profile Service

A Spring Boot REST service that aggregates GitHub user profile data from multiple GitHub API endpoints into a unified response.

Tech Stack

• Java 25
• Spring Boot 4.0.1
• Spring RestClient
• Lombok (minimize boilerplate)
• springdoc-openapi (Swagger)
• JUnit 6 / Mockito (testing)

Architecture

This project uses the following class structure:

ProfileController (REST API)
    └── ProfileService (Business Logic)
            └── GitHubClient (GitHub API Integration)

The profile service will fetch user info and a list of user repositories concurrently from GitHub (using CompletableFuture to minimize wait time), then aggregates them into a single response.

Project Structure

src/main/java/com/branch/service/github/
├── client/           # External API clients (GitHub client)
├── controller/       # REST controllers
│   └── advice/       # Controller advice (i.e - exception handling)
├── exception/        # Custom exception classes
├── model/
│   ├── dto/          # Response DTOs for this service's API
│   └── github/       # DTOs mapping GitHub API responses
└── service/          # Business logic

Build & Run

Command Line

# Build
./mvnw clean compile

# Run tests
./mvnw test

# Run the application
./mvnw spring-boot:run

IntelliJ

Open the project and run the Application class directly (click the play button in the gutter).

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NOTE: The service starts on port 8080 (i.e. http://localhost:8080)

API

Get User Profile

Fetches GitHub user info and repositories.

GET /api/v1/users/{username}/profile

Example Response (200 OK):

{
  "user_name": "octocat",
  "display_name": "The Octocat",
  "avatar": "https://avatars.githubusercontent.com/u/583231",
  "geo_location": "San Francisco",
  "email": "octocat@github.com",
  "url": "https://api.github.com/users/octocat",
  "created_at": "Tue, 25 Jan 2011 18:44:36 GMT",
  "repos": [
    {
      "name": "hello-world",
      "url": "https://github.com/octocat/hello-world"
    }
  ],
  "repo_count": 1
}

Possible Error Responses:

Status	Description
404	User not found on GitHub
502	GitHub API error
500	Internal server error

API Documentation

Once the application is running, you can view the Swagger docs here:

• Swagger UI: http://localhost:8080/swagger-ui.html
• OpenAPI spec: http://localhost:8080/v3/api-docs

Configuration

GitHub API base URL can be configured in application.yaml:

github:
  api:
    base-url: https://api.github.com

Testing

Command Line

# Run all tests
./mvnw test

# Run a specific test class
./mvnw test -Dtest=ProfileControllerTest

IntelliJ

Right-click on a test class or method and select "Run", or click the play button in the gutter.

Classes Under Test

Class Under Test	Layer	Mocking Approach
ProfileControllerTest	Controller	@WebMvcTest + @MockitoBean
ProfileServiceTest	Service	@ExtendWith(MockitoExtension.class) + @Mock