Quote Generator - Microservices Architecture

A modern quote generator built with microservices architecture, demonstrating best practices in web development. Built with Node.js, ASP.NET Core, TypeScript, React, Fastify, MongoDB, PostgreSQL, RabbitMQ, and Docker. Features include: Clean Architecture, DDD, Event-Driven Architecture, CQRS, automated testing, and comprehensive API documentation.

Overview

Built with a focus on scalability, reliability and performance, this application demonstrates modern backend development best practices including:

• Clean Architecture principles
• Domain-Driven Design
• Event-Driven Architecture
• SOLID principles
• Comprehensive testing
• Docker containerization

🛠 Tech Stack

Backend Services

• Auth Service: Node.js + TypeScript + Fastify + MongoDB
• Quote Service: Node.js + TypeScript + Fastify + MongoDB
• User Service: ASP.NET Core 8.0 + PostgreSQL
• API Gateway: Node.js + TypeScript + Fastify

Frontend

• Framework: React 18
• State Management: Redux Toolkit
• Styling: CSS Modules
• Build Tool: Vite

Infrastructure

• Message Broker: RabbitMQ
• Databases:
  • MongoDB (Auth & Quotes)
  • PostgreSQL (Users)
• Containerization: Docker + Docker Compose
• API Documentation: Swagger/OpenAPI

🏗 Architecture & Patterns

Clean Architecture

• Domain Layer (Entities, Value Objects)
• Application Layer (Use Cases, DTOs)
• Infrastructure Layer (Repositories, External Services)
• Interface Layer (Controllers, Presenters)

Domain-Driven Design (DDD)

• Bounded Contexts
• Aggregates
• Value Objects
• Domain Events
• Repository Pattern

Event-Driven Architecture

• Asynchronous Communication
• Message Queues
• Event Publishing/Subscription
• Event Sourcing

CQRS (Command Query Responsibility Segregation)

• Separate Command and Query Models
• Optimized Read/Write Operations

🔧 Design Patterns

• Repository Pattern
• Factory Pattern
• Strategy Pattern
• Observer Pattern
• Circuit Breaker
• Retry Pattern
• Decorator Pattern

🏭 CI/CD & DevOps

• GitHub Actions
• Docker Containerization
• Infrastructure as Code
• Automated Testing
• Continuous Integration
• Continuous Deployment

📊 Testing Strategies

• Unit Tests (Jest, xUnit)
• Integration Tests
• E2E Tests
• Test Coverage Reports
• Mocking & Stubbing

🛡 Security

• JWT Authentication
• Role-Based Access Control
• API Gateway Security
• Input Validation
• Rate Limiting
• CORS Configuration

🎯 Best Practices

Code Quality

• TypeScript for Type Safety
• ESLint & Prettier
• SOLID Principles
• Clean Code Practices
• Code Reviews
• Documentation

Architecture

The application consists of several independent microservices:

• API Gateway: Single entry point for clients
• Auth Service: Authentication and JWT management
• Quote Service: Quote management and retrieval
• User Service: User profiles and preferences management
• Frontend: React user interface

Service Communication

• Synchronous communication via HTTP/REST between services
• Asynchronous communication via RabbitMQ for events
• JWT for inter-service security

Authentication process and retrieval of a quote

sequenceDiagram
    participant Client
    participant Gateway
    participant AuthService
    participant QuoteService
    participant UserService
    participant RabbitMQ

    Client->>Gateway: POST /auth/login
    Gateway->>AuthService: Forward login request
    AuthService->>AuthService: Validate credentials
    AuthService-->>Gateway: Return JWT token
    Gateway-->>Client: Return JWT token

    Client->>Gateway: GET /quotes/random (with JWT)
    Gateway->>Gateway: Validate JWT
    Gateway->>QuoteService: Forward request
    QuoteService->>QuoteService: Generate random quote
    QuoteService->>RabbitMQ: Publish quote.viewed event
    QuoteService-->>Gateway: Return quote
    Gateway-->>Client: Return quote

    RabbitMQ->>UserService: Consume quote.viewed event
    UserService->>UserService: Update user history

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Add to Favorites process

sequenceDiagram
    participant Client
    participant Gateway
    participant QuoteService
    participant UserService
    participant RabbitMQ

    Client->>Gateway: POST /quotes/:id/favorite
    Gateway->>Gateway: Validate JWT
    Gateway->>QuoteService: Forward favorite request
    QuoteService->>RabbitMQ: Publish quote.favorited event
    QuoteService-->>Gateway: Return success
    Gateway-->>Client: Return success

    RabbitMQ->>UserService: Consume quote.favorited event
    UserService->>UserService: Add to favorites
    UserService->>UserService: Update user stats

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New user registration process

sequenceDiagram
    participant Client
    participant Gateway
    participant AuthService
    participant UserService
    participant RabbitMQ

    Client->>Gateway: POST /auth/register
    Gateway->>AuthService: Forward register request
    AuthService->>AuthService: Validate input
    AuthService->>AuthService: Hash password
    AuthService->>AuthService: Create user
    AuthService->>RabbitMQ: Publish user.created event
    AuthService-->>Gateway: Return success + JWT
    Gateway-->>Client: Return success + JWT

    RabbitMQ->>UserService: Consume user.created event
    UserService->>UserService: Create user profile
    UserService->>UserService: Initialize preferences

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Getting Started

Prerequisites

• Node.js >= 20.x
• Docker & Docker Compose

Installation

1. Clone the repository:

git clone https://github.com/your-username/quote-generator.git
cd quote-generator

2. Install dependencies:

npm install

3. Configuration:

• Copy .env.example to .env
• Adjust environment variables

4. Start services:

# Development mode
npm run dev

# Production mode
npm run prod

Service Architecture

1. API Gateway (Port 3000)

• Single entry point
• Request routing
• JWT validation
• CORS configuration

2. Auth Service (Port 3001)

• User registration/login
• JWT generation/validation
• User event publishing

3. Quote Service (Port 3002)

• Quote CRUD operations
• Search and filtering
• Random quote generation
• Tags and categories

4. User Service (Port 3003)

• User profiles
• Reading preferences
• Favorite quotes
• Usage statistics

5. Frontend (Port 3006)

• Modern React interface
• Redux state management
• Offline support
• Responsive design

Event-Driven Architecture

The application leverages RabbitMQ for asynchronous service communication:

User Events

• USER_CREATED
• USER_UPDATED
• USER_DELETED

Quote Events

• QUOTE_VIEWED
• QUOTE_FAVORITED
• QUOTE_UNFAVORITED

Testing

# Unit tests
npm run test

# Coverage report
npm run test:coverage 

API Documentation

Swagger documentation is available at:

• Gateway: /documentation
• Auth: /documentation
• Quote: /documentation
• User: /documentation

Environment Variables

Key environment variables needed:

# JWT Configuration
JWT_SECRET=your_jwt_secret
JWT_EXPIRES_IN=1h

# Services URLs
AUTH_SERVICE_URL=http://localhost:3001
QUOTE_SERVICE_URL=http://localhost:3002
USER_SERVICE_URL=http://localhost:3003

# MongoDB Configuration
MONGO_URL=mongodb://localhost:27017/quote_generator

# RabbitMQ
MESSAGE_BROKER_URL=amqp://guest:guest@localhost:5672

Docker Support

Build and run with Docker Compose:

# Build services
docker-compose build

# Start services
docker-compose up

# Start services with build
docker-compose up --build

# Stop services
docker-compose down

Accessing the Application

Once all services are running, you can access the application through your web browser:

http://localhost:3006

Development

Code Style

• ESLint for linting
• Prettier for code formatting
• Husky for pre-commit hooks

Security

• JWT authentication
• Rate limiting
• CORS protection
• Input validation
• Security headers

License

Distributed under the MIT License. See LICENSE for more information.