Collaborative Document Store

A production-ready collaborative wiki backend built with Node.js, Express.js, and MongoDB. Features optimistic concurrency control (OCC), full-text search, aggregation analytics, JWT authentication, and schema migration strategies.

Features

• JWT Authentication: Token-based auth protecting all mutating endpoints (POST, PUT, DELETE)
• Optimistic Concurrency Control (OCC): Prevents lost updates during collaborative editing without locking
• Full-Text Search: MongoDB $text index with relevance scoring, tag filtering, and pagination
• Advanced Aggregations: Analytics endpoints for document edit counts and tag co-occurrences
• Schema Migrations: Dual strategy — lazy on-read transformation + background batch migration script
• Input Validation: Zod-based schema validation on all inputs
• Security Hardened: Helmet.js security headers and express-rate-limit
• Real Content Diffs: Uses the diff library to generate proper unified diffs for revision history

Architecture

Client → [JWT Auth] → Express.js API → MongoDB 7
                                ↑
                    Migration Script (batch)

• Backend API: Express.js REST API with modular route handlers. All business logic (OCC, schema migration, analytics) is encapsulated in route modules.
• Database: MongoDB 7 in Docker. Documents collection stores content, metadata, and a capped revision history (last 20 entries) in a single document for optimized reads.
• Auth: JWT tokens issued via POST /api/auth/token. Protected routes validate the Authorization: Bearer <token> header.

Prerequisites

• Docker and Docker Compose

Quick Start

1. Clone the repository:

   git clone https://github.com/nnssprasad97/collaborative-document-store.git
   cd collaborative-document-store

2. Start services:

   docker-compose up --build

   This will:

   • Start MongoDB 7 with a health check
   • Build and start the Node.js API on port 3000
   • Auto-seed 10,000 documents on first run
   • Create text and unique indexes

3. The API is available at http://localhost:3000

API Endpoints

Authentication

Method	Endpoint	Description
POST	/api/auth/token	Get a JWT token (provide id, name, email)

Documents

Method	Endpoint	Auth	Description
POST	/api/documents	✅	Create a new document
GET	/api/documents/:slug	❌	Retrieve a document by slug
PUT	/api/documents/:slug	✅	Update with OCC (send version)
DELETE	/api/documents/:slug	✅	Delete a document

Search

Method	Endpoint	Description
GET	/api/search?q=<term>&tags=<t1>,<t2>&page=1&limit=20	Full-text search with tag filtering and pagination

Analytics

Method	Endpoint	Description
GET	/api/analytics/most-edited?limit=10	Top N most-edited documents
GET	/api/analytics/tag-cooccurrence?limit=50	Tag pair co-occurrence frequency

Running Tests

Tests use Jest + Supertest and require a running MongoDB instance:

# With Docker MongoDB running:
npm test

Running the Migration Script

# Inside the Docker container:
docker-compose exec api node scripts/migrate_author_schema.js

# Or locally:
node scripts/migrate_author_schema.js

Environment Variables

See .env.example for all required variables:

Variable	Description	Default
MONGO_URI	MongoDB connection string	mongodb://localhost:27017/collab_docs
DATABASE_NAME	Database name	collab_docs
PORT	API server port	3000
JWT_SECRET	Secret for JWT signing	(required)

Project Structure

├── docker-compose.yml      # Docker orchestration
├── Dockerfile              # API container build
├── package.json            # Dependencies and scripts
├── .env.example            # Environment variable docs
├── src/
│   ├── server.js           # Express app entry point
│   ├── db.js               # MongoDB connection + index management
│   ├── seed.js             # Database seeding (10,000 docs)
│   ├── middleware/
│   │   └── auth.js         # JWT authentication middleware
│   └── routes/
│       ├── auth.js         # Token generation endpoint
│       ├── documents.js    # CRUD + OCC endpoints
│       ├── search.js       # Full-text search endpoint
│       └── analytics.js    # Aggregation pipeline endpoints
├── scripts/
│   └── migrate_author_schema.js  # Background schema migration
└── tests/
    └── api.test.js         # Integration test suite