KnowHow - Educational Platform for Knowledge Sharing

About the Project

KnowHow is a microservices-based educational platform that allows users to create, sell, and purchase educational courses. The system includes moderation functionality, rating systems, user balance management, and email notifications.

Key Features

• Authentication and authorization using JWT tokens stored in cookies
• Course creation and management with moderation system
• Balance system for purchasing courses with internal currency
• Rating system for course evaluation by users
• Email notifications for events (verification, purchase, moderation)
• Tags and search for convenient course navigation
• User profiles with purchase history and ratings

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Microservices

1. Core Service — main service implementing business logic:

   • User management
   • Course CRUD operations
   • Moderation system
   • Course purchasing
   • Ratings
   • Balance management

2. Notification Service — notification service:

   • Email sending
   • RabbitMQ event processing
   • Processing statistics

3. Shared — shared library:

   • Event DTOs
   • Common models and utilities

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Technology Stack

Core Service

Technology	Version	Purpose
Java	21	Main language
Spring Boot	-	Framework
Spring Security	-	Authentication and authorization
Spring Data JPA	-	ORM and database operations
PostgreSQL	17.5	Primary database
Redis	7.2	Caching, verification code storage
RabbitMQ	4.2	Message broker
MapStruct	-	Object mapping
Nimbus JOSE JWT	-	JWT tokens
Flyway	-	Database migrations
Resilience4j	-	Retry mechanisms
SpringDoc OpenAPI	-	Swagger documentation

Notification Service

Technology
Spring Boot Starter Mail
Spring AMQP

Infrastructure

Component
Docker
Jib
Lombok

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Installation and Setup

Prerequisites

• JDK 21 or higher
• Maven 3.9+
• Docker and Docker Compose

Step 1: Clone Repository

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

Step 2: Build Project

mvn clean package

Step 3: Start with Docker Compose

docker-compose up -d

Step 4: Verify

• Swagger UI: http://localhost:8080/swagger-ui.html
• RabbitMQ Management: http://localhost:15672 (admin/admin123)

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API Endpoints

Authentication

Method	URL	Description
POST	/api/v1/auth/reg	User registration
POST	/api/v1/auth/login	Login
GET	/api/v1/auth/me	Current user info
POST	/api/v1/auth/logout	Logout

Courses

Method	URL	Description
POST	/api/v1/courses	Create course
GET	/api/v1/courses/search	Search courses
GET	/api/v1/courses/{id}	Get course by ID
POST	/api/v1/courses/pay/{id}	Purchase course
PUT	/api/v1/courses/retry-pass-moderation/{id}	Resubmit for moderation
DELETE	/api/v1/courses/{id}	Delete course

Moderation

Method	URL	Description
POST	/api/v1/courses/moderation/{id}/approve	Approve course
POST	/api/v1/courses/moderation/{id}/reject	Reject course
GET	/api/v1/courses/moderation/queue/on_moderation	Courses in moderation

User

Method	URL	Description
GET	/api/v1/profile	User profile
GET	/api/v1/users/purchased-courses	Purchased courses
DELETE	/api/v1/users	Delete account
PATCH	/api/v1/users/contact/email	Update email

Balance

Method	URL	Description
GET	/api/v1/balance/history	Transaction history
PATCH	/api/v1/balance	Update balance

Ratings

Method	URL	Description
POST	/api/v1/courses/{courseId}/rating	Rate course

Tags

Method	URL	Description
GET	/api/v1/tags	Get all tags

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Security

Authentication

• JWT tokens in HttpOnly cookies
• CSRF protection with tokens
• BCrypt for password hashing

Docker

Building Images

# Build core-service
cd core-service
mvn compile jib:build

# Build notification-service
cd notification-service
mvn compile jib:build

Docker Compose Commands

# Start all services
docker-compose up -d

# View logs
docker-compose logs -f

# Stop
docker-compose down

# Stop with volume removal
docker-compose down -v

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Monitoring

RabbitMQ Metrics

• Confirm logging every 10 minutes
• Success/failure statistics

Notification Statistics

• Logging every 60 minutes
• Success/failure processing counts
• Messages per second throughput

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License

This project is distributed under the MIT License. See LICENSE file for details.

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Contact

• Email: slava.vy.2006@gmail.com
• Telegram: @perunve

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Acknowledgments

• Spring Framework
• T-Bank Education
• All project contributors