📂 CloudVault: Enterprise File Management System

CloudVault is a high-performance, layered backend API built with Node.js, Express, and Prisma. It provides a robust architecture for managing hierarchical file systems, recursive folder operations, and automated cloud synchronization.

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🏗 System Architecture

The project follows a Layered Architecture (Controller-Service-Model) to ensure separation of concerns, maintainability, and ease of testing.

1. Route Layer

• Defines API endpoints.
• Applies JWT authentication and Multer file-processing middleware.
• Integrates Zod schemas for strict request validation.

2. Controller Layer

• Orchestrates the request/response lifecycle.
• Extracts validated data and passes it to the Service layer.
• Uses next(error) to delegate exceptions to the global error handler.

3. Service Layer

• Contains core business logic.
• Handles complex operations like permission checks and business-level data transformations.
• Coordinates multiple model calls for complex workflows.

4. Model Layer

• Direct interaction with PostgreSQL via Prisma ORM.
• Interaction with Cloudinary API for media persistence.
• Handles low-level data errors and rethrows them with contextual logging.

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🛠 Tech Stack

Category	Technology
Runtime	Node.js (Express.js)
Database	PostgreSQL + Prisma ORM
Cloud Storage	Cloudinary (Media hosting)
Security	JWT (Auth), Bcrypt (Hashing)
Validation	Zod
File Handling	Multer

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🔐 Key Logic & Error Handling

Recursive Operations

The system handles complex folder trees. When deleting a folder, the logic identifies all nested sub-folders and files, purges the media from Cloudinary using publicId, and cleans up the database metadata in a cascaded flow.

Global Error Pipeline

Errors follow a "bubble-up" pattern:

1. Model/Service: Throws an error.
2. Controller: Catches the error and calls next(error).
3. Middleware: A centralized handler formats the error and sends a clean JSON response (e.g., 404 Not Found or 400 Validation Error).

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🔌 API Endpoints

📁 Folders

• POST /api/folders - Create a new folder (supports nesting).
• GET /api/folders - Fetch user folders (supports root-only filtering).
• DELETE /api/folders/:id - Delete folder (checks for empty or supports recursive purge).

📄 Files

• POST /api/files/upload - Secure file upload via Multer to Cloudinary.
• POST /api/files/avatar - Upsert logic for user profile pictures.
• GET /api/files/:id - Retrieve metadata and secure cloud URL.
• GET /api/files/stats - Aggregated storage usage and file-type breakdown.

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🚀 Getting Started

1. Clone the repository and run npm install.
2. Environment Setup: Create a .env file with DATABASE_URL, JWT_SECRET, and CLOUDINARY_URL.
3. Prisma Setup:

   npx prisma generate
   npx prisma db push

4. Run Development:

   npm run dev

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🧪 Testing & Documentation

• Integration Tests: Handled via Jest and Supertest.
• Validation: All incoming request bodies are strictly typed with Zod to prevent SQL injection and malformed data.