python-fastapi-patternslisted
Install: claude install-skill aiskillstore/marketplace
# FastAPI Patterns
Modern async API development with FastAPI.
## Basic Application
```python
from fastapi import FastAPI
from contextlib import asynccontextmanager
@asynccontextmanager
async def lifespan(app: FastAPI):
"""Application lifespan - startup and shutdown."""
# Startup
app.state.db = await create_db_pool()
yield
# Shutdown
await app.state.db.close()
app = FastAPI(
title="My API",
version="1.0.0",
lifespan=lifespan,
)
@app.get("/")
async def root():
return {"message": "Hello World"}
```
## Request/Response Models
```python
from pydantic import BaseModel, Field, EmailStr
from datetime import datetime
class UserCreate(BaseModel):
"""Request model with validation."""
name: str = Field(..., min_length=1, max_length=100)
email: EmailStr
age: int = Field(..., ge=0, le=150)
class UserResponse(BaseModel):
"""Response model."""
id: int
name: str
email: EmailStr
created_at: datetime
model_config = {"from_attributes": True} # Enable ORM mode
@app.post("/users", response_model=UserResponse, status_code=201)
async def create_user(user: UserCreate):
db_user = await create_user_in_db(user)
return db_user
```
## Path and Query Parameters
```python
from fastapi import Query, Path
from typing import Annotated
@app.get("/users/{user_id}")
async def get_user(
user_id: Annotated[int, Path(..., ge=1, description="User ID")],
):
return await fetch_user(user_id)
@app.get("/users"