feat: Add modular architecture, MSSR pattern, and full project generation

[mE-uMAr]

feat: Add modular architecture, MSSR pattern, and full project generation

Summary

Transforms fastapi-new from a basic project initializer into a complete modular project generator with professional architecture patterns and CLI tools.

Before → After

Before:

• Only generated main.py with basic FastAPI setup

After:

• Full project structure with modular architecture
• MSSR pattern (Model-Schema-Service-Repository)
• Complete CLI toolset for development
• Auto-registration system
• Multi-database support

New Features

🏗️ Modular Architecture

• Auto-registration of application modules via INSTALLED_APPS
• Clean separation with core/, apps/, and db/ directories
• Automatic route discovery and loading

📦 MSSR Pattern

New createapp command generates structured modules:

app/apps/users/
├── models.py        # Data models
├── schemas.py       # Pydantic validation
├── services.py      # Business logic
├── repositories.py  # Data access
├── routes.py        # API endpoints
└── dependencies.py  # FastAPI dependencies

🔧 New CLI Commands

• fastapi-new createapp <name> - Generate MSSR modules
• fastapi-new add-db <engine> - Configure database (postgres/mysql/sqlite/mongodb)
• fastapi-new list - View installed modules
• fastapi-new doctor - Diagnose project health

📁 Complete Project Structure

myproject/
├── app/
│   ├── main.py          # Enhanced with auto-registration
│   ├── core/            # Configuration & utilities
│   ├── apps/            # Application modules
│   └── db/              # Database layer
├── .env                 # Environment config
└── pyproject.toml

Usage Example

# Create project with full structure
fastapi-new myapi
cd myapi

# Generate modules
fastapi-new createapp users
fastapi-new createapp products

# Configure database
fastapi-new add-db postgres --install

# Start server
uv run fastapi dev

Technical Details

• Templates: 20+ .tpl files for clean code generation
• Tests: 28 comprehensive tests covering all CLI commands
• Python: 3.10+ support
• Philosophy: Minimal boilerplate (~157 lines of starter code), maximum flexibility

Changes

Added Files

• CLI commands: createapp.py, adddb.py, listapps.py, doctor.py
• Templates: templates/project/ (13 files), templates/app/ (7 files)
• Tests: Full coverage for new features
• Utilities: Template engine and CLI helpers

Enhanced

• new.py - Now generates complete structure instead of just main.py
• README - Complete rewrite in FastAPI official docs style

Testing

✅ 28 tests, all passing
✅ Multi-OS (Linux, macOS, Windows)
✅ Python 3.10-3.14

Breaking Changes

None - existing usage continues to work with enhanced features.

---

Type: Feature Enhancement
Impact: High - Major new functionality
Docs: Complete

[github-actions]

This pull request has a merge conflict that needs to be resolved.

[github-actions]

This pull request has a merge conflict that needs to be resolved.

[tiangolo]

Thanks! We'll gradually add new features here, one by one, after careful consideration for each one.

It will also be done in independent small PRs.

For now, I'll pass on this. ☕