learning from 《python web开发从入门到精通》

1. 安装 SQLAlchemy

• pip install sqlalchemy

2. 创建数据库

• mysql -u root -p 命令行登录 MySQL

创建数据库 fastapi_db

mysql> create database fastapi_db default charset utf8mb4 collate utf8mb4_unicode_ci;
Query OK, 1 row affected (0.04 sec)

3. SQLAlchemy 连接 MySQL

• database.py

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base# 数据库连接配置
SQLALCHEMY_DATABASE_URI = ("mysql+pymysql://root:123456@localhost/fastapi_db?charset=utf8mb4"#                用户:密码@服务器/数据库?参数
)# 创建数据库引擎
engine = create_engine(SQLALCHEMY_DATABASE_URI)
# 创建数据库会话
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
# 声明基类
Base = declarative_base()

4. 创建数据模型

• models.py

from sqlalchemy import Boolean, Column, ForeignKey, Integer, String
from sqlalchemy.orm import relationship
from .database import Base# 定义 User 类
class User(Base):__tablename__ = 'users'  # 定义表名id = Column(Integer, primary_key=True, index=True)email = Column(String(255), unique=True, index=True)hashed_password = Column(String(255))is_active = Column(Boolean, default=True)items = relationship("Item", back_populates="owner")# 关联 Item 表# 定义 Item 类
class Item(Base):__tablename__ = "items"id = Column(Integer, primary_key=True, index=True)title = Column(String(255), index=True)description = Column(String(255), index=True)owner_id = Column(Integer, ForeignKey('users.id'))owner = relationship("User", back_populates="items")# 关联 User 表

relationship 还不懂，有待学习 SQLAlchemy

5. 创建 Pydantic 模型

• schemas.py

from typing import List
from pydantic import BaseModelclass ItemBase(BaseModel):title: strdescription: str = Noneclass ItemCreate(ItemBase):passclass Item(ItemBase):id: intowner_id: intclass Config:orm_mode = Trueclass UserBase(BaseModel):email: strclass UserCreate(UserBase):password: strclass User(UserBase):id: intis_active: boolitems: List[Item] = []class Config:orm_mode = True

6. crud 工具

• crud.py

from sqlalchemy.orm import Sessionfrom . import models, schemasdef get_user(db: Session, user_id: int):"""根据id获取用户信息:param db: 数据库会话:param user_id: 用户id:return: 用户信息"""return db.query(models.User).filter(models.User.id == user_id).first()def get_user_by_email(db: Session, email: str):"""根据email获取用户信息:param db: 数据库会话:param email: 用户email:return: 用户信息"""return db.query(models.User).filter(models.User.email == email).first()def get_users(db: Session, skip: int = 0, limit: int = 100):"""获取特定数量的用户:param db: 数据库会话:param skip: 开始位置:param limit: 限制数量:return: 用户信息列表"""return db.query(models.User).offset(skip).limit(limit).all()def create_user(db: Session, user: schemas.UserCreate):"""创建用户:param db: 数据库会话:param user: 用户模型:return: 根据email和password登录的用户信息"""fake_hashed_password = user.password + "notreallyhashed"db_user = models.User(email=user.email, hashed_password=fake_hashed_password)db.add(db_user)      # 添加到会话db.commit()          # 提交到数据库db.refresh(db_user)  # 刷新数据库return db_userdef get_items(db: Session, skip: int = 0, limit: int = 100):"""获取指定数量的item:param db: 数据库会话:param skip: 开始位置:param limit: 限制数量:return: item列表"""return db.query(models.Item).offset(skip).limit(limit).all()def create_user_item(db: Session, item: schemas.ItemCreate, user_id: int):"""创建用户item:param db: 数据库会话:param item: Item对象:param user_id: 用户id:return: Item模型对象"""db_item = models.Item(**item.dict(), owner_id=user_id)db.add(db_item)db.commit()db.refresh(db_item)return db_item

7. main函数

from typing import Listfrom fastapi import Depends, FastAPI, HTTPException
from sqlalchemy.orm import Sessionfrom . import crud, models, schemas
from .database import SessionLocal, enginemodels.Base.metadata.create_all(bind=engine)app = FastAPI()# 依赖
def get_db():try:db = SessionLocal()yield dbfinally:db.close()@app.post("/users/", response_model=schemas.User)
def create_user(user: schemas.UserCreate, db: Session = Depends(get_db)):# 根据email查找用户db_user = crud.get_user_by_email(db, email=user.email)# 如果用户存在，提示该邮箱已经被注册if db_user:raise HTTPException(status_code=400, detail="Email already registered")# 返回创建的user对象return crud.create_user(db=db, user=user)@app.get("/users/", response_model=List[schemas.User])
def read_users(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):# 读取指定数量用户users = crud.get_users(db, skip=skip, limit=limit)return users@app.get("/users/{user_id}", response_model=schemas.User)
def read_user(user_id: int, db: Session = Depends(get_db)):# 获取当前id的用户信息db_user = crud.get_user(db, user_id=user_id)# 如果没有信息，提示用户不存在if db_user is None:raise HTTPException(status_code=404, detail="User not found")return db_user@app.post("/users/{user_id}/items/", response_model=schemas.Item)
def create_item_for_user(user_id: int, item: schemas.ItemCreate, db: Session = Depends(get_db)
):# 创建该用户的itemsreturn crud.create_user_item(db=db, item=item, user_id=user_id)@app.get("/items/", response_model=List[schemas.Item])
def read_items(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):# 获取所有itemsitems = crud.get_items(db, skip=skip, limit=limit)return items

(pt19) D:\web_python_dev>uvicorn fastapi_mysql.main:app --reload
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:     Started reloader process [6988] using watchgod
INFO:     Started server process [2112]
INFO:     Waiting for application startup.
INFO:     Application startup complete.

mysql> use fastapi_db
Database changed
mysql> show tables;
+----------------------+
| Tables_in_fastapi_db |
+----------------------+
| items                |
| users                |
+----------------------+
2 rows in set (0.00 sec)

在网页里发送一个 post 请求后，查询 sql

mysql> select * from users;
+----+----------------+---------------------+-----------+
| id | email          | hashed_password     | is_active |
+----+----------------+---------------------+-----------+
|  1 | michael@xx.com | abcdnotreallyhashed |         1 |
+----+----------------+---------------------+-----------+
1 row in set (0.00 sec)