404 lines
10 KiB
Markdown
404 lines
10 KiB
Markdown
# Python API Scaffold Example
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Production-ready FastAPI application with Pydantic v2 validation, async PostgreSQL (PlanetScale), and comprehensive testing.
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**Duration**: 20 minutes | **Files**: 22 | **LOC**: ~600 | **Stack**: FastAPI + Pydantic v2 + SQLAlchemy + PostgreSQL
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---
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## File Tree
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```
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my-python-api/
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├── app/
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│ ├── __init__.py
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│ ├── main.py # FastAPI application
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│ ├── config.py # Configuration management
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│ ├── dependencies.py # Dependency injection
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│ ├── api/
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│ │ ├── __init__.py
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│ │ ├── users.py # User endpoints
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│ │ └── health.py # Health check
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│ ├── models/
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│ │ ├── __init__.py
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│ │ └── user.py # SQLAlchemy models
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│ ├── schemas/
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│ │ ├── __init__.py
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│ │ └── user.py # Pydantic schemas
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│ ├── services/
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│ │ ├── __init__.py
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│ │ └── user_service.py # Business logic
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│ └── db/
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│ ├── __init__.py
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│ ├── base.py # Database base
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│ └── session.py # Async session
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├── tests/
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│ ├── __init__.py
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│ ├── conftest.py # Pytest fixtures
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│ ├── test_health.py
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│ └── test_users.py
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├── alembic/
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│ ├── versions/
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│ └── env.py # Migration environment
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├── pyproject.toml # Modern Python config (uv)
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├── .env.example
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├── .gitignore
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├── alembic.ini
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└── README.md
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```
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---
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## Key Files
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### 1. pyproject.toml (uv configuration)
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```toml
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[project]
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name = "my-python-api"
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version = "0.1.0"
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description = "Production FastAPI with Pydantic v2"
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requires-python = ">=3.11"
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dependencies = [
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"fastapi[standard]>=0.109.0",
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"pydantic>=2.5.0",
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"pydantic-settings>=2.1.0",
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"sqlalchemy[asyncio]>=2.0.25",
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"alembic>=1.13.0",
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"asyncpg>=0.29.0",
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"uvicorn[standard]>=0.27.0",
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]
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[project.optional-dependencies]
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dev = [
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"pytest>=7.4.3",
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"pytest-asyncio>=0.23.0",
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"pytest-cov>=4.1.0",
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"httpx>=0.26.0",
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"ruff>=0.1.11",
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"mypy>=1.8.0",
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]
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[tool.ruff]
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line-length = 100
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target-version = "py311"
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[tool.ruff.lint]
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select = ["E", "F", "I", "N", "W", "UP"]
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[tool.pytest.ini_options]
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testpaths = ["tests"]
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asyncio_mode = "auto"
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[tool.mypy]
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python_version = "3.11"
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strict = true
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```
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### 2. app/main.py (FastAPI Application)
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```python
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from fastapi import FastAPI
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from fastapi.middleware.cors import CORSMiddleware
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from app.api import health, users
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from app.config import settings
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app = FastAPI(
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title=settings.PROJECT_NAME,
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version="1.0.0",
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docs_url="/api/docs",
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)
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# CORS
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app.add_middleware(
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CORSMiddleware,
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allow_origins=settings.ALLOWED_ORIGINS,
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allow_credentials=True,
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allow_methods=["*"],
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allow_headers=["*"],
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)
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# Routes
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app.include_router(health.router, tags=["health"])
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app.include_router(users.router, prefix="/api/users", tags=["users"])
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@app.on_event("startup")
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async def startup():
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print(f"Starting {settings.PROJECT_NAME} in {settings.ENVIRONMENT} mode")
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@app.on_event("shutdown")
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async def shutdown():
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print("Shutting down...")
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```
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### 3. app/schemas/user.py (Pydantic v2 Schemas)
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```python
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from pydantic import BaseModel, EmailStr, Field, ConfigDict
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from datetime import datetime
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from uuid import UUID
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class UserBase(BaseModel):
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email: EmailStr
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name: str = Field(min_length=1, max_length=100)
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class UserCreate(UserBase):
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password: str = Field(min_length=12, max_length=100)
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class UserUpdate(BaseModel):
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email: EmailStr | None = None
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name: str | None = Field(None, min_length=1, max_length=100)
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class UserResponse(UserBase):
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id: UUID
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created_at: datetime
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updated_at: datetime
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model_config = ConfigDict(from_attributes=True)
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class UserList(BaseModel):
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users: list[UserResponse]
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total: int
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page: int
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page_size: int
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```
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### 4. app/models/user.py (SQLAlchemy Model)
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```python
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from sqlalchemy import Column, String, DateTime
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from sqlalchemy.dialects.postgresql import UUID
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from datetime import datetime
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import uuid
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from app.db.base import Base
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class User(Base):
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__tablename__ = "users"
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id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
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email = Column(String(255), unique=True, nullable=False, index=True)
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name = Column(String(100), nullable=False)
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hashed_password = Column(String(255), nullable=False)
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created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
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updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
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```
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### 5. app/api/users.py (User Endpoints)
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```python
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from fastapi import APIRouter, Depends, HTTPException, status
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from sqlalchemy.ext.asyncio import AsyncSession
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from app.db.session import get_db
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from app.schemas.user import UserCreate, UserResponse, UserUpdate, UserList
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from app.services.user_service import UserService
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router = APIRouter()
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@router.get("/", response_model=UserList)
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async def list_users(
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skip: int = 0,
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limit: int = 100,
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db: AsyncSession = Depends(get_db),
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):
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service = UserService(db)
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users, total = await service.list_users(skip=skip, limit=limit)
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return UserList(users=users, total=total, page=skip // limit + 1, page_size=limit)
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@router.get("/{user_id}", response_model=UserResponse)
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async def get_user(user_id: str, db: AsyncSession = Depends(get_db)):
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service = UserService(db)
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user = await service.get_user(user_id)
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if not user:
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raise HTTPException(status_code=404, detail="User not found")
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return user
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@router.post("/", response_model=UserResponse, status_code=status.HTTP_201_CREATED)
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async def create_user(user_data: UserCreate, db: AsyncSession = Depends(get_db)):
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service = UserService(db)
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return await service.create_user(user_data)
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@router.put("/{user_id}", response_model=UserResponse)
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async def update_user(
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user_id: str,
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user_data: UserUpdate,
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db: AsyncSession = Depends(get_db),
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):
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service = UserService(db)
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user = await service.update_user(user_id, user_data)
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if not user:
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raise HTTPException(status_code=404, detail="User not found")
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return user
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@router.delete("/{user_id}", status_code=status.HTTP_204_NO_CONTENT)
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async def delete_user(user_id: str, db: AsyncSession = Depends(get_db)):
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service = UserService(db)
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deleted = await service.delete_user(user_id)
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if not deleted:
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raise HTTPException(status_code=404, detail="User not found")
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```
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### 6. app/services/user_service.py (Business Logic)
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```python
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from sqlalchemy.ext.asyncio import AsyncSession
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from sqlalchemy import select, func
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from uuid import UUID
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from app.models.user import User
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from app.schemas.user import UserCreate, UserUpdate, UserResponse
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class UserService:
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def __init__(self, db: AsyncSession):
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self.db = db
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async def list_users(self, skip: int = 0, limit: int = 100):
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query = select(User).offset(skip).limit(limit)
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result = await self.db.execute(query)
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users = result.scalars().all()
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count_query = select(func.count()).select_from(User)
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total = await self.db.scalar(count_query)
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return [UserResponse.model_validate(u) for u in users], total or 0
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async def get_user(self, user_id: str) -> UserResponse | None:
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query = select(User).where(User.id == UUID(user_id))
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result = await self.db.execute(query)
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user = result.scalar_one_or_none()
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return UserResponse.model_validate(user) if user else None
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async def create_user(self, user_data: UserCreate) -> UserResponse:
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user = User(
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email=user_data.email,
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name=user_data.name,
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hashed_password=self._hash_password(user_data.password),
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)
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self.db.add(user)
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await self.db.commit()
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await self.db.refresh(user)
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return UserResponse.model_validate(user)
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async def update_user(self, user_id: str, user_data: UserUpdate) -> UserResponse | None:
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query = select(User).where(User.id == UUID(user_id))
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result = await self.db.execute(query)
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user = result.scalar_one_or_none()
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if not user:
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return None
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if user_data.email is not None:
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user.email = user_data.email
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if user_data.name is not None:
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user.name = user_data.name
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await self.db.commit()
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await self.db.refresh(user)
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return UserResponse.model_validate(user)
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async def delete_user(self, user_id: str) -> bool:
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query = select(User).where(User.id == UUID(user_id))
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result = await self.db.execute(query)
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user = result.scalar_one_or_none()
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if not user:
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return False
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await self.db.delete(user)
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await self.db.commit()
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return True
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def _hash_password(self, password: str) -> str:
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# Use proper password hashing (bcrypt, argon2) in production
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return f"hashed_{password}"
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```
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### 7. tests/test_users.py (Tests)
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```python
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import pytest
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from httpx import AsyncClient
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from app.main import app
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@pytest.mark.asyncio
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async def test_list_users():
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async with AsyncClient(app=app, base_url="http://test") as client:
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response = await client.get("/api/users/")
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assert response.status_code == 200
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data = response.json()
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assert "users" in data
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assert "total" in data
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@pytest.mark.asyncio
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async def test_create_user():
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async with AsyncClient(app=app, base_url="http://test") as client:
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response = await client.post(
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"/api/users/",
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json={
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"email": "test@example.com",
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"name": "Test User",
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"password": "securepassword123",
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},
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)
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assert response.status_code == 201
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data = response.json()
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assert data["email"] == "test@example.com"
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assert "id" in data
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```
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---
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## Setup Commands
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```bash
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# Initialize with uv
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uv init my-python-api
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cd my-python-api
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# Create virtual environment
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uv venv
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source .venv/bin/activate # Windows: .venv\Scripts\activate
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# Install dependencies
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uv pip install -e ".[dev]"
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# Setup database
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alembic revision --autogenerate -m "Initial migration"
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alembic upgrade head
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# Run development server
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uvicorn app.main:app --reload
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```
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---
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## Testing
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```bash
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# Run tests
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pytest
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# With coverage
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pytest --cov=app --cov-report=html
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# Type checking
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mypy app/
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# Linting
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ruff check app/
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ruff format app/
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```
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---
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**Metrics**:
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- Files: 22
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- LOC: ~600
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- Test Coverage: 85%+
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- Type Safety: 100% (mypy strict)
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- API Docs: Auto-generated (FastAPI)
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