之前我们创建的文件都是在一个目录中，但是在我们的实际开发中，肯定不能这样设计，那么我们去创建一个目录，叫models，大致如下。

主要目录是：

· __init__.py 是一个空文件，说明models是一个package

· crud.py 数据库操作相关

· database.py 数据库配置相关

· models.py 数据库模型表

· schemas.py 模型验证

· main.py 主文件

database.py代码如下：

from sqlalchemy import create_engine
from sqlalchemy.orm import declarative_base
from sqlalchemy.orm import sessionmaker

conn = "mysql+pymysql://{username}:{password}@{host}:{port}/{database}?charset=utf8".format(
    username="root", password="123456", host="10.30.10.36", port=3306, database="fastapi_learn_road")
engine = create_engine(conn)

# 该类的每个实例都是一个数据库会话，该类本身还不是数据库会话，但是一旦我们创建了SessionLocal的实例，这个实例将是实际的数据库会话
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# 创建数据库基类
Base = declarative_base()

models.py代码如下：

from sqlalchemy import Boolean, Column, ForeignKey, Integer, String
from sqlalchemy.orm import relationship
from .database import Base


class User(Base):
    __tablename__ = "users"

    id = Column(Integer, primary_key=True, index=True)
    email = Column(String(10), unique=True, index=True)
    hashed_password = Column(String(100))
    is_active = Column(Boolean, default=True)
    items = relationship("Item", back_populates="owner")


class Item(Base):
    __tablename__ = "items"

    id = Column(Integer, primary_key=True, index=True)
    title = Column(String(10), index=True)
    description = Column(String(10), index=True)
    owner_id = Column(Integer, ForeignKey("users.id"))
    owner = relationship("User", back_populates="items")

schemas.py代码如下：定义请求参数模型验证与响应模型验证的Pydantic模型。

from pydantic import BaseModel
from typing import List, Optional


class BaseItem(BaseModel):
    title: str
    description: Optional[str] = None


class ItemModel(BaseItem):
    pass


class ItemOut(BaseItem):
    id: int
    owner_id: int

    class Config:
        orm_mode = True


class BaseUser(BaseModel):
    email: str


class UserModel(BaseUser):
    """请求参数模型"""
    password: str


class UserOut(BaseUser):
    """响应模型"""
    id: int
    is_active: bool
    items: List[ItemOut]

    class Comfig:
        orm_mode = True

crud.py代码如下：

# 之前都是把所有逻辑写到了接口函数里，其实我们应该抽出来，一起管理
from fastapi import HTTPException
from sqlalchemy.orm import Session
from .models import *
from .schemas import *


def get_user_method(db: Session, uid: int):
    user = db.query(User).filter(User.id == uid).first()
    if not user:
        raise HTTPException(status_code=404, detail="user not exists")
    return user


def create_user_method(db: Session, user: UserModel):
    db_user = db.query(User).filter(User.email == user.email).first()
    if db_user:
        raise HTTPException(status_code=200, detail="this user already exists")
    fake_hashed_password = user.password + "_hashed"
    init_user = User(email=user.email, hashed_password=fake_hashed_password)
    db.add(init_user)
    db.commit()
    db.refresh(init_user)
    return init_user


def get_items_method(db: Session, skip: int = 0, limit: int = 10):
    return db.query(Item).offset(skip).limit(limit).all()


def get_items_by_uid_method(db: Session, uid: int):
    user = db.query(User).filter(User.id == uid).first()
    if not user:
        raise HTTPException(status_code=200, detail="this user is not valid")
    return db.query(Item).filter(Item.owner == user).offset(0).limit(2).all()


def create_item_by_user_method(db: Session, uid: int, item: ItemModel):
    init_item = Item(**item.dict(), owner_id=uid)
    db.add(init_item)
    db.commit()
    db.refresh(init_item)
    return init_item

main.py代码如下：

from fastapi import FastAPI, Depends, HTTPException
from models.crud import *
from models.database import *


app = FastAPI()


def create_db():
    """每个请求处理完毕后关闭当前连接，不同的请求使用不同的链接"""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


@app.post("/user", response_model=UserOut)
def create_user(user: UserModel, db: Session = Depends(create_db)):
    return create_user_method(db, user)


@app.get("/user", response_model=UserOut)
def get_user(uid: int, db: Session = Depends(create_db)):
    return get_user_method(db, uid)


@app.post("/items/{uid}", response_model=ItemOut)
def create_item_by_user(uid: int, item: ItemModel, db: Session = Depends(create_db)):
    return create_item_by_user_method(db, uid, item)


@app.get("/items", response_model=List[ItemOut])
def get_items(skip: int = 0, limit: int = 10, db: Session = Depends(create_db)):
    return get_items_method(db, skip, limit)


@app.get("/items/{uid}", response_model=List[ItemOut])
def get_items_by_uid(uid: int, db: Session = Depends(create_db)):
    return get_items_by_uid_method(db, uid)


if __name__ == '__main__':
    import uvicorn
    uvicorn.run("main:app", reload=True)

我们目前是这么改造的。后续还会持续改造的。目前我们没有对API接口main文件进行改造，下面的分享我们会对api接口做改造。