基于FastApi的介绍与应用

FastAPI简介FastAPI是一个现代、快速高性能的Web框架用于基于Python构建API。它基于标准Python类型提示使用Starlette和Pydantic库支持异步请求处理。主要特点包括高性能与NodeJS和Go相当快速开发代码自动补全和类型检查自动生成文档支持OpenAPI和JSON Schema易于学习简洁直观的API设计安装FastAPI安装FastAPI和ASGI服务器如Uvicorn​ pip install fastapi uvicorn ​基本应用示例创建一个简单的FastAPI应用from fastapi import FastAPI app FastAPI() app.get(/) async def read_root(): return {message: Hello World} app.get(/items/{item_id}) async def read_item(item_id: int, q: str None): return {item_id: item_id, q: q}运行应用uvicorn main:app --reload请求与响应模型使用Pydantic模型定义数据结构和验证from pydantic import BaseModel class Item(BaseModel): name: str description: str None price: float tax: float None app.post(/items/) async def create_item(item: Item): return item路径参数与查询参数app.get(/users/{user_id}) async def read_user(user_id: int, limit: int 10, skip: int 0): return {user_id: user_id, limit: limit, skip: skip}异步支持FastAPI原生支持异步请求处理import httpx app.get(/async-example/) async def async_request(): async with httpx.AsyncClient() as client: response await client.get(https://httpbin.org/get) return response.json()自动文档启动应用后访问以下URL查看自动生成的文档http://127.0.0.1:8000/docs交互式Swagger UIhttp://127.0.0.1:8000/redocReDoc文档数据库集成示例使用SQLAlchemy集成数据库from sqlalchemy import create_engine, Column, Integer, String from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.orm import sessionmaker SQLALCHEMY_DATABASE_URL sqlite:///./test.db engine create_engine(SQLALCHEMY_DATABASE_URL) SessionLocal sessionmaker(autocommitFalse, autoflushFalse, bindengine) Base declarative_base() class User(Base): __tablename__ users id Column(Integer, primary_keyTrue, indexTrue) name Column(String) email Column(String, uniqueTrue) Base.metadata.create_all(bindengine) app.post(/users/) async def create_user(name: str, email: str): db SessionLocal() user User(namename, emailemail) db.add(user) db.commit() db.refresh(user) return user中间件示例添加自定义中间件from fastapi import Request app.middleware(http) async def add_process_time_header(request: Request, call_next): response await call_next(request) response.headers[X-Custom-Header] FastAPI return response部署建议生产环境部署推荐使用Gunicorn作为进程管理器配合Uvicorn工作进程gunicorn -w 4 -k uvicorn.workers.UvicornWorker main:app配置Nginx作为反向代理使用Docker容器化部署以上内容涵盖了FastAPI的核心功能和应用场景可根据实际需求进一步扩展和定制。