Python FastAPI 入门实战：从零构建生产级 RESTful API

启动服务：

uvicorn main:app --reload

浏览器访问 http://127.0.0.1:8000 看到 JSON 即成功。再访问 http://127.0.0.1:8000/docs 即可看到自动生成的 Swagger 界面。

核心概念速览

理解以下概念有助于建立心智模型：

经典入门案例：图书管理 API

我们用一个简易图书管理系统贯穿演示，边学边写。

数据模型定义 (models.py)

使用 Pydantic 进行数据校验和序列化。

from pydantic import BaseModel, Field
from typing import Optional

class BookBase(BaseModel):
    title: str = Field(..., min_length=1, max_length=100)
    author: str = Field(..., min_length=1, max_length=50)
    year: int = Field(..., ge=1900, le=2100)

class BookCreate(BookBase):
    pass

class Book(BookBase):
    id: int
    is_available: bool = True

    class Config:
        from_attributes = True  # 兼容 ORM

实现路由逻辑 (main.py)

逐步添加增删改查功能。

from fastapi import FastAPI, HTTPException, Query, Path
from typing import List
from models import Book, BookCreate

app = FastAPI(title="图书管理 API", version="0.1.0")

# 假数据库
books_db: List[Book] = [
    Book(id=1, title="Python 速成", author="重阳", year=2025),
]

@app.get("/books/", response_model=List[Book])
def get_books(
    skip: int = Query(0, ge=0),
    limit: int = Query(10, ge=1, le=100),
    author: Optional[str] = None
):
    result = books_db[skip : skip + limit]
    if author:
        result = [b for b in result if b.author.lower() == author.lower()]
    return result

@app.get("/books/{book_id}", response_model=Book)
def get_book(book_id: int = Path(..., ge=1)):
    for book in books_db:
        if book.id == book_id:
            return book
    raise HTTPException(status_code=404, detail="图书不存在")

@app.post("/books/", response_model=Book, status_code=201)
def create_book(book: BookCreate):
    new_id = max(b.id for b in books_db) + 1 if books_db else 1
    new_book = Book(id=new_id, **book.model_dump())
    books_db.append(new_book)
    return new_book

启动后直接在 Swagger 上测试增删改查。后续可进一步深入数据库连接（SQLAlchemy + asyncpg）、JWT 认证、项目结构组织及 Docker 部署等内容。