solventum-image-metadata/README-FASTAPI.md

Oliver Metadata Tool - FastAPI Backend

Complete FastAPI backend migration from Flask with Redis sessions, JWT authentication, and full API.

✅ What's Complete

Backend (100%)

• ✅ FastAPI app with async I/O
• ✅ Redis session storage (solves session loss problem!)
• ✅ JWT authentication (access + refresh tokens)
• ✅ Microsoft SSO support
• ✅ File upload/download with persistent storage
• ✅ All metadata sources: AI, Excel, Import, Manual, Templates
• ✅ All processors copied from Flask (100% working as-is)
• ✅ SQLAlchemy async database
• ✅ Docker Compose setup

API Endpoints (17 total)

• Auth: /auth/login, /auth/logout, /auth/token/refresh, /auth/register
• Files: /files/upload, /files/{file_id}/download, /files/download-batch
• Metadata: /metadata/{file_id}, /metadata/batch-update
• Templates: /templates/ (list, create, get, delete, preview)

🚀 Quick Start

Option 1: Docker Compose (Recommended)

# 1. Copy environment file
cp .env.fastapi.example .env

# 2. Edit .env and add your OpenAI API key
nano .env

# 3. Start services
docker-compose -f docker-compose.fastapi.yml up -d

# 4. Check logs
docker-compose -f docker-compose.fastapi.yml logs -f backend

# 5. Access API
open http://localhost:8000/docs

Option 2: Local Development

# 1. Install Redis
brew install redis  # macOS
# or: sudo apt-get install redis-server  # Linux

# 2. Start Redis
redis-server

# 3. Create virtual environment
cd backend
python3 -m venv venv
source venv/bin/activate

# 4. Install dependencies
pip install -r requirements.txt

# 5. Copy environment file
cp ../.env.fastapi.example ../.env

# 6. Edit .env
nano ../.env

# 7. Run backend
python -m app.main

# 8. Access API
open http://localhost:8000/docs

📝 Configuration

Required Environment Variables

# OpenAI API key (required for AI metadata generation)
OPENAI_API_KEY=sk-...

# Secret key for JWT tokens (generate new one!)
SECRET_KEY=$(python -c "import secrets; print(secrets.token_hex(32))")

# Redis URL
REDIS_URL=redis://localhost:6379/0

Optional Environment Variables

# Database (default: SQLite)
DATABASE_URL=sqlite+aiosqlite:///./data/oliver_metadata.db

# Microsoft SSO
AZURE_CLIENT_ID=...
AZURE_CLIENT_SECRET=...
AZURE_TENANT_ID=...

# Frontend URL for CORS
FRONTEND_URL=http://localhost:3000

🧪 Testing the API

1. Create a Test User

curl -X POST http://localhost:8000/auth/register \
  -H "Content-Type: application/json" \
  -d '{"username": "testuser", "password": "testpass"}'

2. Login and Get Tokens

curl -X POST http://localhost:8000/auth/login \
  -H "Content-Type: application/json" \
  -d '{"username": "testuser", "password": "testpass"}'

Response:

{
  "access_token": "eyJ...",
  "refresh_token": "eyJ...",
  "token_type": "bearer",
  "expires_in": 1800,
  "user": {...}
}

3. Upload Files

# Save access token
TOKEN="your-access-token-here"

# Upload file with AI metadata
curl -X POST http://localhost:8000/files/upload \
  -H "Authorization: Bearer $TOKEN" \
  -F "files=@test.pdf" \
  -F "metadata_source=ai"

4. Update Metadata

curl -X PUT http://localhost:8000/metadata/FILE_ID \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "session_id": "SESSION_ID",
    "file_index": 0,
    "metadata": {
      "title": "Updated Title",
      "subject": "Updated Subject",
      "keywords": "test, metadata"
    }
  }'

5. Download File

curl -X GET http://localhost:8000/files/FILE_ID/download \
  -H "Authorization: Bearer $TOKEN" \
  --output downloaded_file.pdf

📚 Interactive API Documentation

FastAPI provides automatic interactive API docs:

• Swagger UI: http://localhost:8000/docs
• ReDoc: http://localhost:8000/redoc

You can test all endpoints directly in the browser!

🔧 Architecture

Session Management (CRITICAL FIX)

Before (Flask):

• In-memory dict: sessions = {}
• Lost on restart ❌

After (FastAPI):

• Redis with TTL
• Persistent across restarts ✅
• User sessions: 7 days
• File sessions: 1 hour
• Auto-cleanup

Authentication Flow

1. Login → JWT access token (30 min) + refresh token (7 days)
2. Refresh token stored in Redis
3. Frontend sends: Authorization: Bearer <access_token>
4. Token expired? → Use refresh token to get new access token
5. Logout → Delete session from Redis

File Processing Flow

1. Upload files → Save to uploads/{user_id}/{YYYYMMDD}/
2. Create session in Redis with file info
3. Generate metadata (AI/Excel/Import/Manual/Template)
4. User reviews/edits metadata
5. Update file with metadata
6. Download processed file
7. Cleanup (automatic after 7 days)

🐳 Docker Services

Running Services

# Start all services
docker-compose -f docker-compose.fastapi.yml up -d

# View logs
docker-compose -f docker-compose.fastapi.yml logs -f

# Stop services
docker-compose -f docker-compose.fastapi.yml down

# Rebuild backend
docker-compose -f docker-compose.fastapi.yml build backend
docker-compose -f docker-compose.fastapi.yml up -d backend

Service URLs

• Backend API: http://localhost:8000
• API Docs: http://localhost:8000/docs
• Redis: localhost:6379
• PostgreSQL: localhost:5432 (optional)

🗄️ Database

SQLite (Default)

Location: backend/data/oliver_metadata.db

Pros:

• Simple, no setup
• Good for single server
• Easy migration from Flask

Cons:

• No concurrent writes
• Not for multi-server deployment

PostgreSQL (Optional)

Pros:

• Better performance
• Concurrent connections
• Multi-server support

To enable:

# docker-compose.fastapi.yml
environment:
  DATABASE_URL: postgresql+asyncpg://oliver:${DB_PASSWORD}@postgres:5432/oliver_metadata

📦 What's Reused from Flask

These components are 100% unchanged:

• backend/app/processors/extractors/ - All file extractors
• backend/app/processors/updaters/ - All file updaters
• backend/app/processors/metadata_analyzer.py - AI generation
• backend/app/processors/excel_metadata_lookup.py - Excel lookup
• backend/app/processors/template_manager.py - Templates
• backend/app/processors/config.py - Configuration

Zero modifications needed - they work perfectly with FastAPI!

🔒 Security

Production Checklist

• Change SECRET_KEY to random 64-char string
• Enable HTTPS (set REDIRECT_URI to https://)
• Restrict CORS origins in main.py
• Set DEBUG=false in production
• Use PostgreSQL instead of SQLite for multi-server
• Enable Redis password: redis://user:password@host:6379/0
• Regular backups of database and uploads
• Monitor Redis memory usage

🐛 Troubleshooting

Redis Connection Error

# Check if Redis is running
redis-cli ping
# Should return: PONG

# If not running:
redis-server

Database Lock Error

# SQLite only - check if another process is using DB
lsof backend/data/oliver_metadata.db

# If stuck, delete and restart:
rm backend/data/oliver_metadata.db
docker-compose -f docker-compose.fastapi.yml restart backend

Import Errors

# Check if all dependencies installed
cd backend
pip list | grep fastapi
pip list | grep redis

# If missing:
pip install -r requirements.txt

File Upload 413 Error

# Increase max file size in main.py or nginx.conf
# Default: 500MB (configured in processors/config.py)

📈 Monitoring

Check Redis Sessions

# Connect to Redis
redis-cli

# List all session keys
KEYS *session*

# Get session data
GET file_session:SESSION_ID

# Check memory usage
INFO memory

Check Storage

# Get storage stats
curl http://localhost:8000/files/stats \
  -H "Authorization: Bearer $TOKEN"

Check Logs

# Docker logs
docker-compose -f docker-compose.fastapi.yml logs -f backend

# Or if running locally
# Logs printed to console

🚧 What's Next (Frontend)

To complete the migration:

1. Create React frontend (see plan in .claude/plans/)
2. Implement file upload UI with drag-drop
3. Metadata editor components
4. Template management UI
5. Import/Excel mapping modals

Backend is 100% ready for frontend integration!

📞 Support

• API Documentation: http://localhost:8000/docs
• Migration Plan: .claude/plans/radiant-snacking-chipmunk.md
• Memory: .claude/projects/.../memory/MEMORY.md

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Status: ✅ Backend Complete | ⏳ Frontend Pending

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