第2章 - 项目搭建

"""
项目配置文件
"""

class Settings:
    # 项目信息
    PROJECT_NAME: str = "学生管理系统"
    PROJECT_VERSION: str = "1.0.0"
    PROJECT_DESCRIPTION: str = "一个基于 FastAPI 的学生管理系统"
    
    # 数据库配置
    DATABASE_URL: str = "sqlite:///./student.db"
    
    # 如果使用 MySQL，配置如下：
    # DATABASE_URL: str = "mysql+pymysql://user:password@localhost:3306/student_db"
    
    # API 前缀
    API_PREFIX: str = "/api"

settings = Settings()

"""
数据库配置
"""
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

from app.config import settings

# 创建数据库引擎
engine = create_engine(
    settings.DATABASE_URL,
    connect_args={"check_same_thread": False}  # SQLite 需要
)

# 创建会话工厂
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# 创建基类
Base = declarative_base()

def get_db():
    """获取数据库会话"""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

"""
统一响应模型
"""
from typing import Generic, TypeVar, Optional, List
from pydantic import BaseModel

T = TypeVar('T')

class ResponseModel(BaseModel, Generic[T]):
    """通用响应模型"""
    code: int = 200
    message: str = "success"
    data: Optional[T] = None

class PageData(BaseModel, Generic[T]):
    """分页数据模型"""
    items: List[T]
    total: int
    page: int
    size: int
    pages: int

def success(data=None, message: str = "success"):
    """成功响应"""
    return ResponseModel(code=200, message=message, data=data)

def error(code: int = 400, message: str = "error"):
    """错误响应"""
    return ResponseModel(code=code, message=message, data=None)

def page_response(items: list, total: int, page: int, size: int):
    """分页响应"""
    pages = (total + size - 1) // size  # 计算总页数
    return ResponseModel(
        code=200,
        message="success",
        data=PageData(
            items=items,
            total=total,
            page=page,
            size=size,
            pages=pages
        )
    )

"""
主程序入口
"""
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

from app.config import settings
from app.database import engine, Base

# 创建数据库表（后面会添加模型后生效）
Base.metadata.create_all(bind=engine)

# ��建 FastAPI 应用
app = FastAPI(
    title=settings.PROJECT_NAME,
    description=settings.PROJECT_DESCRIPTION,
    version=settings.PROJECT_VERSION,
    docs_url="/docs",
    redoc_url="/redoc"
)

# 配置 CORS（跨域）
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # 生产环境应该设置具体的域名
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# 根路由
@app.get("/")
def root():
    return {
        "message": "欢迎使用学生管理系统",
        "docs": "/docs",
        "redoc": "/redoc"
    }

# 健康检查
@app.get("/health")
def health_check():
    return {"status": "healthy"}

# 后面会在这里注册路由
# from app.api import students, classes, scores, statistics
# app.include_router(students.router, prefix=settings.API_PREFIX, tags=["学生管理"])
# app.include_router(classes.router, prefix=settings.API_PREFIX, tags=["班级管理"])
# app.include_router(scores.router, prefix=settings.API_PREFIX, tags=["成绩管理"])
# app.include_router(statistics.router, prefix=settings.API_PREFIX, tags=["数据统计"])