CourseMarket - Mini Udemy + Uber Hybrid Platform

A demonstration project combining Udemy-style course marketplace with Uber-style instructor matching, built with .NET 8 Web API and React 18.

Project Overview

CourseMarket is a hybrid learning platform that offers:

1. Udemy Flow: Browse courses, purchase with Stripe, access purchased content
2. Uber Logic: Request personalized live lessons with automatic instructor matching

Key Features

• Three user roles (User, Instructor, Admin) with JWT authentication
• Course marketplace with search and pagination
• Secure payment processing with Stripe
• Intelligent instructor matching algorithm
• Live lesson request system
• Responsive React UI with Tailwind CSS
• Clean Architecture backend with CQRS pattern

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Technology Stack

Backend

• .NET 8 Web API
• Entity Framework Core 8 + SQLite
• MediatR (CQRS pattern)
• JWT Bearer Authentication
• Stripe.net SDK
• BCrypt for password hashing
• Swagger/OpenAPI documentation

Frontend

• React 18 + TypeScript
• Vite (build tool)
• Tailwind CSS
• React Query (@tanstack/react-query)
• Zustand (state management)
• React Router v6
• Axios

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Prerequisites

• .NET 8 SDK
• Node.js 18+
• Stripe CLI (optional, for webhook testing)

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Getting Started

1. Clone the Repository

cd /path/to/your/projects
# Project is already in: uber_and_udemy_project/

2. Backend Setup

Install Dependencies & Run Migrations

cd backend/src/CourseMarket.API
dotnet restore
dotnet ef database update

Configure Settings

The appsettings.json is already configured with:

• JWT Secret: YourSuperSecretKeyThatIsAtLeast32CharactersLongForHS256Algorithm
• Stripe Test Keys: (Replace with your own from Stripe Dashboard)

{
  "Stripe": {
    "SecretKey": "sk_test_...",
    "PublishableKey": "pk_test_...",
    "WebhookSecret": "whsec_..."
  }
}

Run the Backend

dotnet run

The API will be available at:

• HTTP: http://localhost:5032
• Swagger: http://localhost:5032/swagger

3. Frontend Setup

Install Dependencies

cd frontend
npm install

Configure Environment

The .env file is already configured:

VITE_API_URL=http://localhost:5032/api
VITE_STRIPE_PUBLISHABLE_KEY=pk_test_your_key_here

Replace the Stripe publishable key with your own.

Run the Frontend

npm run dev

The app will be available at:

• Frontend: http://localhost:5173

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Test Credentials

The database is pre-seeded with test accounts:

Admin Account

Email: admin@coursemarket.com
Password: Admin123!

Instructor Accounts

Email: john.instructor@coursemarket.com
Password: Instructor123!
Role: Instructor (Web Development)

Email: jane.instructor@coursemarket.com
Password: Instructor123!
Role: Instructor (Data Science)

Email: mike.instructor@coursemarket.com
Password: Instructor123!
Role: Instructor (Design)

User Accounts

Email: alice@coursemarket.com
Password: User123!
Role: User

Email: bob@coursemarket.com
Password: User123!
Role: User

... (4 more users: charlie, diana, eve, fiona)

---

Stripe Test Cards

Use these test cards for payment testing:

Card Number	Scenario	Expected Result
4242 4242 4242 4242	Success	Payment succeeds
4000 0000 0000 0002	Decline	Card declined
4000 0025 0000 3155	Auth Required	Requires 3D Secure

Expiry Date: Any future date (e.g., 12/34) CVC: Any 3 digits (e.g., 123) ZIP: Any 5 digits (e.g., 12345)

---

API Endpoints

Authentication

Method	Endpoint	Description	Auth Required
POST	/api/auth/register	Create new account	No
POST	/api/auth/login	Authenticate user	No
GET	/api/auth/me	Get current user	Yes

Courses

Method	Endpoint	Description	Auth Required	Role
GET	/api/courses	List all courses (paginated)	No	-
GET	/api/courses/{id}	Get course details	No	-
GET	/api/courses/my-courses	Get purchased courses	Yes	Any
POST	/api/courses	Create new course	Yes	Instructor/Admin
PUT	/api/courses/{id}	Update course	Yes	Instructor/Admin

Query Parameters for GET /api/courses:

• page (default: 1)
• pageSize (default: 10)
• search (optional)

Purchases

Method	Endpoint	Description	Auth Required
POST	/api/purchases/create-payment-intent	Start purchase flow	Yes
POST	/api/purchases/confirm	Confirm and complete purchase	Yes
GET	/api/purchases/my-purchases	Get purchase history	Yes

Live Lessons

Method	Endpoint	Description	Auth Required	Role
POST	/api/live-lessons/requests	Create lesson request	Yes	User
GET	/api/live-lessons/my-requests	Get user's requests	Yes	User
GET	/api/live-lessons/assigned	Get assigned lessons	Yes	Instructor
PATCH	/api/live-lessons/requests/{id}/status	Update request status	Yes	Instructor/Admin

Notifications

Method	Endpoint	Description	Auth Required
GET	/api/notifications	Get user's notifications	Yes
PATCH	/api/notifications/{id}/read	Mark notification as read	Yes
PATCH	/api/notifications/mark-all-read	Mark all as read	Yes

Webhooks

Method	Endpoint	Description	Auth Required
POST	/api/webhooks/stripe	Stripe webhook handler	No (signature validated)

---

Project Structure

uber_and_udemy_project/
├── backend/
│   ├── CourseMarket.sln
│   └── src/
│       ├── CourseMarket.Domain/          # Entities, Enums
│       ├── CourseMarket.Application/     # CQRS Commands/Queries
│       ├── CourseMarket.Infrastructure/  # DbContext, Services
│       └── CourseMarket.API/            # Controllers, Program.cs
└── frontend/
    ├── src/
    │   ├── api/           # Axios client + endpoints
    │   ├── components/    # Reusable UI components
    │   ├── pages/         # Route-level pages
    │   ├── store/         # Zustand stores
    │   ├── types/         # TypeScript interfaces
    │   └── App.tsx        # Router configuration
    ├── package.json
    └── vite.config.ts

---

How It Works

1. Course Purchase Flow (Udemy Logic)

1. User browses courses at /courses
2. Clicks on course to view details at /courses/{id}
3. Clicks "Purchase Course" button
4. Backend creates Stripe PaymentIntent and returns clientSecret
5. Frontend shows Stripe checkout form (in demo: auto-confirms)
6. Payment succeeds → Backend verifies and creates Purchase record
7. Course is added to user's "My Courses"
8. Stripe webhook (async) validates and logs transaction

2. Live Lesson Matching (Uber Logic)

1. User navigates to /live-lessons and clicks "Request Live Lesson"
2. Fills out form: topic, description, preferred date, duration
3. Submits request → Backend triggers matching algorithm
4. Matching Algorithm scores all instructors:
   • Topic Relevance: +10 points if instructor teaches related courses
   • Availability: -2 points per active assignment
   • Random Factor: +0-5 for variety
5. Best instructor is automatically assigned
6. InstructorAssignment record created with match score
7. Notification sent to instructor
8. User sees assigned instructor on /live-lessons
9. Instructor sees assignment on /instructor/dashboard

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Testing the Application

Test Scenario 1: Purchase a Course

1. Register new account or login with alice@coursemarket.com / User123!
2. Navigate to "Browse Courses"
3. Click on any course (e.g., "Complete React Masterclass")
4. Click "Purchase Course"
5. In demo mode: automatically confirms purchase
6. Navigate to "My Courses" to see purchased course

Test Scenario 2: Request Live Lesson

1. Login as a user (e.g., bob@coursemarket.com / User123!)
2. Navigate to "Live Lessons"
3. Click "Request Live Lesson"
4. Fill in:
   • Topic: "Advanced TypeScript"
   • Description: "Need help understanding generics"
   • Preferred Date: Any future date/time
   • Duration: 60 minutes
5. Submit → System automatically matches best instructor
6. View assignment with instructor details and match score

Test Scenario 3: Instructor Dashboard

1. Login as instructor (john.instructor@coursemarket.com / Instructor123!)
2. Navigate to "Instructor Dashboard"
3. View assigned live lesson requests
4. See match scores and student information

---

Webhook Testing (Optional)

To test Stripe webhooks locally:

1. Install Stripe CLI
2. Login: stripe login
3. Forward webhooks:

   stripe listen --forward-to localhost:5032/api/webhooks/stripe

4. Copy the webhook signing secret (starts with whsec_)
5. Update appsettings.json with the new WebhookSecret
6. Trigger test events:

   stripe trigger payment_intent.succeeded

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Database Management

View Database

# Install SQLite browser (optional)
# macOS: brew install --cask db-browser-for-sqlite
# Windows: Download from https://sqlitebrowser.org/

# Database file location
backend/src/CourseMarket.API/coursemarket.db

Reset Database

cd backend/src/CourseMarket.API
rm -f coursemarket.db*
dotnet ef database update

This will:

1. Delete existing database
2. Re-run migrations
3. Re-seed test data

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Architecture

This project follows Clean Architecture principles. For detailed information about:

• Technology choices and rationale
• Payment flow diagrams
• Instructor matching algorithm
• Scalability strategy

See: ARCHITECTURE.md

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Key Architectural Patterns

Backend

• Clean Architecture: Domain → Application → Infrastructure → API
• CQRS: Commands (writes) and Queries (reads) separated via MediatR
• Repository Pattern: EF Core DbContext as Unit of Work
• Dependency Injection: Built-in .NET DI container

Frontend

• Container/Presentational: Smart components with hooks vs pure UI
• Custom Hooks: Encapsulate React Query logic
• Protected Routes: HOC pattern for authentication/authorization
• Atomic Design: Reusable UI components (Button, Input, Card)

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Common Issues & Solutions

Issue: Backend port already in use

Solution:

# Change port in backend/src/CourseMarket.API/Properties/launchSettings.json
"applicationUrl": "http://localhost:YOUR_PORT"

Issue: Database migration errors

Solution:

cd backend/src/CourseMarket.API
dotnet ef database drop --force
dotnet ef database update

Issue: CORS errors in frontend

Solution:

• Ensure backend is running on http://localhost:5032
• Check that frontend .env has correct VITE_API_URL
• Verify CORS policy in Program.cs includes frontend origin

Issue: Stripe payments not working

Solution:

• Use test card: 4242 4242 4242 4242
• Verify Stripe keys in appsettings.json and .env
• Check browser console for errors
• Ensure using test mode keys (start with pk_test_ and sk_test_)

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Performance Considerations

• Pagination: All list endpoints support page/pageSize
• Database Indexes: Foreign keys indexed for fast queries
• React Query Caching: 5-minute stale time reduces API calls
• Code Splitting: React Router lazy loading for routes

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Security Features

• Password Hashing: BCrypt with salt rounds
• JWT Tokens: 7-day expiration, role-based claims
• Role-based Authorization: [Authorize(Roles = "Instructor,Admin")]
• Stripe Security: PCI compliance via Stripe.js, webhook signature validation
• SQL Injection Protection: EF Core parameterizes all queries
• XSS Protection: React escapes output by default

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Future Enhancements

• Real-time notifications with SignalR
• Course reviews and ratings
• Video upload and streaming
• Instructor availability calendar
• Email notifications
• Admin dashboard with analytics
• Full Stripe checkout integration (not just PaymentIntent)
• Unit and integration tests
• CI/CD pipeline
• Deployment to Azure/AWS

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License

This is a demonstration project for educational purposes.

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Contact & Support

For issues or questions:

• Open an issue on the repository
• Review the ARCHITECTURE.md for technical details

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Acknowledgments

Built with:

• .NET 8
• React 18
• Stripe
• Tailwind CSS
• Entity Framework Core
• MediatR
• React Query

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Happy Coding! 🚀