586 lines
19 KiB
Markdown
586 lines
19 KiB
Markdown
# 一、简介
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  [FastAPI](https://fastapi.tiangolo.com/zh/) 是一个用于构建 API 的现代、快速（高性能）的 web 框架，使用 Python 并基于标准的 Python 类型提示。
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  安装：
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```cmd
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pip install fastapi
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pip install uvicorn[standard] # ASGI服务器
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```
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# 二、数据层
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## 2.1 数据库ORM SQLAlchemy
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### 2.1.1 配置与连接
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```python
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# database.py - 数据库配置
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from sqlalchemy import create_engine, MetaData
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from sqlalchemy.ext.declarative import declarative_base
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from sqlalchemy.orm import sessionmaker, Session
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from typing import Generator
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import os
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from dotenv import load_dotenv
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load_dotenv()
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# 数据库配置
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DATABASE_URL = f"mysql+pymysql://{os.getenv("DATABASE_URL", "root:123456@127.0.0.1:3306/test")}"
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# 创建引擎
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engine = create_engine(
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DATABASE_URL,
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echo=True, # 显示 SQL 语句（开发环境）
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pool_size=20, # 连接池大小
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max_overflow=40, # 最大溢出连接数
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pool_pre_ping=True, # 连接前 ping
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pool_recycle=3600, # 连接回收时间（秒）
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)
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# 创建会话工厂
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SessionLocal = sessionmaker(
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autocommit=False,
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autoflush=False,
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bind=engine,
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expire_on_commit=False, # 提交后不使实例过期
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)
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# 声明基类
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Base = declarative_base()
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# 依赖注入：获取数据库会话
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def get_db() -> Generator[Session, None, None]:
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"""
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获取数据库会话
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使用 yield 确保会话正确关闭
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"""
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db = SessionLocal()
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try:
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yield db
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finally:
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db.close()
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```
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>[!WARNING]
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>需要把pool_pre_ping=True打开，否则会出现超过pool_recycle时间后，数据库断线。
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### 2.1.2 数据库基类
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```python
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from sqlalchemy import Column, BigInteger, String, DateTime, event
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from sqlalchemy.ext.declarative import declared_attr
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from config.auth import context_sub
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from config.database import Base
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from datetime import datetime
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from utils.common import camel_to_snake
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from id_generator import options, generator
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# https://github.com/yitter/IdGenerator/tree/master/Python
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options = options.IdGeneratorOptions(worker_id=23)
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idgen = generator.DefaultIdGenerator()
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idgen.set_id_generator(options)
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# 第二层基类：包含ID
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class IdBase(Base):
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__abstract__ = True
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id = Column(BigInteger, primary_key=True, index=True)
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@declared_attr
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def __tablename__(cls):
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# 自动把数据库实体类名驼峰转为数据库表名下划线
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return camel_to_snake(cls.__name__)
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# 自动填充id
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@event.listens_for(IdBase, 'before_insert', propagate=True)
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def before_insert_listener(mapper, connection, target):
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if target.id is None:
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target.id = idgen.next_id()
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# 第二层基类：包含ID和审计字段
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class AuditBase(IdBase):
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__abstract__ = True
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create_time = Column(DateTime, nullable=True, default=datetime.now)
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create_by = Column(String(255), nullable=True)
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update_time = Column(DateTime, nullable=True, default=datetime.now, onupdate=datetime.now)
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update_by = Column(String(255), nullable=True)
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@event.listens_for(AuditBase, 'before_insert', propagate=True)
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def before_insert(mapper, connection, target):
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value = context_sub.get(None)
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if value is not None:
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target.create_by = value
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@event.listens_for(AuditBase, 'before_update', propagate=True)
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def before_update(mapper, connection, target):
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value = context_sub.get(None)
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if value is not None:
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target.update_by = value
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```
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  id采用yitter雪花id。
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  审计字段中的create_time和update_time通过SQLAlchemy参数配置。
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  create_by和update_by字段为登录认证中存储的账号信息。
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### 2.1.3 数据库模型
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```python
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from sqlalchemy import (BigInteger, Boolean, Column, Integer, DECIMAL, String, LargeBinary)
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from sqlalchemy.orm import relationship
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from models.base import AuditBase, IdBase
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class Blog(AuditBase):
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title = Column(String(255), nullable=False, comment="博客标题")
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top_value = Column(Integer, nullable=False, default=0, comment="置顶值 越大越靠前")
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is_great = Column(Boolean, nullable=False, default=False, comment="是否是精品")
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category_id = Column(BigInteger, nullable=False, comment="博客类别")
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summary = Column(String(255), nullable=False, comment="博客内容概要")
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content_id = Column(BigInteger, nullable=False, comment="博客内容")
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word_count = Column(Integer, nullable=False, default=0, comment="字数统计")
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read_duration = Column(DECIMAL(10, 2), nullable=False, default=0.00, comment="阅读时长")
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is_approved = Column(Boolean, nullable=False, default=False, comment="是否发布")
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# 分类关系（多对一）
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category = relationship(
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"BlogCategory",
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# 与BlogCategory的blogs属性建立双向关系
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back_populates="blogs",
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# 只级联保存和合并操作，不级联删除（删除博客不应删除分类
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cascade="save-update, merge",
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# 明确指定连接条件
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# 如果数据库设置了外键可以省略
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primaryjoin="foreign(Blog.category_id) == BlogCategory.id"
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)
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# 内容关系（一对一）
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content = relationship(
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"BlogContent",
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# 与BlogContent的blog属性建立双向关系
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back_populates="blog",
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# 完全级联操作：保存、合并、刷新、删除等所有操作都会级联
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cascade="all, delete-orphan",
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# 设置为False表示一对一关系，返回单个对象而不是列表
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uselist=False,
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# 确保内容只有一个父博客，与delete-orphan配合使用
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single_parent=True,
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# 明确指定连接条件
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primaryjoin="foreign(Blog.content_id) == BlogContent.id"
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)
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# 评论（一对多）
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comments = relationship(
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"BlogComment",
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# 与BlogComment的blog属性建立双向关系
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back_populates="blog",
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# 完全级联操作：博客删除时自动删除所有评论
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cascade="all, delete-orphan",
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# 明确指定连接条件
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primaryjoin="Blog.id == foreign(BlogComment.blog_id)"
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)
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class BlogCategory(AuditBase):
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name = Column(String(45), nullable=False, comment="类别名称")
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blogs = relationship(
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"Blog",
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# 与Blog的category属性建立双向关系
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back_populates="category",
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# 完全级联操作：分类删除时自动删除所有关联的博客
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# 警告：这会级联删除分类下的所有博客，包括博客的内容、访问记录和评论
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cascade="all, delete-orphan",
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# 明确指定连接条件
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primaryjoin="BlogCategory.id == foreign(Blog.category_id)"
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)
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class BlogContent(IdBase):
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content = Column(LargeBinary, nullable=False, comment="博客内容")
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blog = relationship(
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"Blog",
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# 与Blog的content属性建立双向关系
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back_populates="content",
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# 设置为False表示一对一关系
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uselist=False,
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# 明确指定连接条件
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primaryjoin="BlogContent.id == foreign(Blog.content_id)"
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)
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class BlogComment(AuditBase):
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blog_id = Column(BigInteger, nullable=False, comment="博客ID")
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parent_id = Column(BigInteger, nullable=False, comment="父评论ID")
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name = Column(String(255), nullable=False, comment="评论人昵称")
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website = Column(String(255), nullable=True, comment="评论人网站")
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ip_address = Column(String(45), nullable=False, comment="评论人IP")
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user_agent = Column(String(255), nullable=False, comment="评论人浏览器信息")
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content = Column(String(255), nullable=False, comment="评论内容")
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is_approved = Column(Boolean, nullable=False, default=False, comment="是否通过")
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blog = relationship(
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"Blog",
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# 与Blog的comments属性建立双向关系
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back_populates="comments",
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# 明确指定连接条件
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primaryjoin="foreign(BlogComment.blog_id) == Blog.id"
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)
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```
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  这里没有通过在数据库建立外键，而是通过SQLAlchemy中的relationship来建立。
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  其中primaryjoin明确指定了连接条件。如果为一对一，需要设置uselist=False和single_parent=True，返回单个对象而不是列表。
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  cascade表示级联操作：
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```
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# cascade 的完整可选值列表：
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# 基本级联操作
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"save-update" # 保存/更新时级联
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"merge" # 合并会话时级联
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"refresh-expire" # 刷新过期对象时级联
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"expunge" # 从会话中移除时级联
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"delete" # 删除时级联
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"delete-orphan" # 成为孤儿时删除
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# 快捷组合
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"all" # 包含除 delete-orphan 外的所有操作
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"all, delete-orphan" # 包含所有操作
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"none" # 禁用所有级联（默认）
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# 其他组合
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"save-update, merge" # 常用组合
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"save-update, merge, delete" # 包含删除
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"save-update, merge, refresh-expire"
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```
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## 2.2 数据验证pydantic
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```python
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from typing import Optional
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from pydantic import BaseModel, Field, field_validator
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from datetime import datetime
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class BlogQuery(BaseModel):
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"""博客查询参数"""
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category: Optional[str] = Field(None, description="分类名称")
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title: Optional[str] = Field(None, description="标题关键词")
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year: Optional[int] = Field(None, description="发布年份", ge=2000, le=datetime.now().year)
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@field_validator('year')
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def validate_year(cls, v):
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if v is not None and v > datetime.now().year:
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raise ValueError('年份不能超过当前年份')
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return v
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class BlogBase(BaseModel):
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"""博客基础模型"""
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title: str = Field(..., min_length=1, max_length=255, description="博客标题")
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top_value: int = Field(default=0, ge=0, description="置顶值，越大越靠前", alias="topValue")
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is_great: bool = Field(default=False, description="是否是精品", alias="isGreat")
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category: str = Field(..., min_length=1, max_length=45, description="分类名称")
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content: Optional[str] = Field(None, description="博客内容")
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is_approved: bool = Field(default=False, description="是否已发布", alias="isApproved")
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@field_validator('title')
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def title_not_empty(cls, v):
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if not v or not v.strip():
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raise ValueError('标题不能为空')
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return v.strip()
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@field_validator('category')
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def category_not_empty(cls, v):
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if not v or not v.strip():
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raise ValueError('分类不能为空')
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return v.strip()
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class BlogCreate(BlogBase):
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pass
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class BlogUpdate(BlogBase):
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pass
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class BlogResponse(BlogBase):
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id: int = Field(..., description="博客ID")
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summary: Optional[str] = Field(None, description="内容摘要")
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word_count: Optional[int] = Field(None, description="字数统计", alias="wordCount")
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read_duration: Optional[float] = Field(None, description="阅读时长", alias="readDuration")
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visit_count: Optional[int] = Field(0, description="访问次数", alias="visitCount")
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create_time: datetime = Field(..., description="创建时间", alias="createTime")
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update_time: datetime = Field(..., description="更新时间", alias="updateTime")
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class Config:
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from_attributes = True
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populate_by_name = True
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json_encoders = {
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# 自定义 datetime 类型的序列化格式
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datetime: lambda dt: dt.strftime('%Y-%m-%d %H:%M:%S')
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}
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class BlogCategoryResponse(BaseModel):
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name: str = Field(..., description="分类名称")
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count: int = Field(..., description="博客数量")
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class Config:
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from_attributes = True
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populate_by_name = True
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class BlogStatsResponse(BaseModel):
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blog_count: int = Field(..., description="博客总数", alias="blogCount")
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category_count: int = Field(..., description="分类总数", alias="categoryCount")
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word_count: int = Field(..., description="总字数", alias="wordCount")
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class BlogVisitResponse(BaseModel):
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ip: str = Field(..., description="IP地址")
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os: str = Field(..., description="操作系统")
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browser: str = Field(..., description="浏览器")
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uri: str = Field(..., description="访问路径")
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title: str = Field(None, description="博客标题")
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visit_time: datetime = Field(..., description="访问时间", alias="visitTime")
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class Config:
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from_attributes = True
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populate_by_name = True
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json_encoders = {
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datetime: lambda dt: dt.strftime('%Y-%m-%d %H:%M:%S')
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}
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class BlogLatestResponse(BaseModel):
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id: int = Field(..., description="博客ID")
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title: str = Field(..., description="博客标题")
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class Config:
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from_attributes = True
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populate_by_name = True
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class BlogAdjacentResponse(BaseModel):
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id: int = Field(..., description="博客ID")
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title: str = Field(..., description="博客标题")
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class Config:
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from_attributes = True
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populate_by_name = True
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class BlogCommentCreate(BaseModel):
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parent_id: int = Field(default=0, ge=0, description="父评论ID，0表示顶级评论", alias="parentId")
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name: str = Field(..., min_length=1, max_length=50, description="评论人昵称")
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website: Optional[str] = Field(None, description="评论人网站")
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content: str = Field(..., min_length=1, max_length=1000, description="评论内容")
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@field_validator('name')
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def name_not_empty(cls, v):
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if not v or not v.strip():
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raise ValueError('昵称不能为空')
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return v.strip()
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@field_validator('content')
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def content_not_empty(cls, v):
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if not v or not v.strip():
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raise ValueError('评论内容不能为空')
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return v.strip()
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class BlogCommentResponse(BlogCommentCreate):
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id: int = Field(..., description="评论ID")
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ip_address: str = Field(..., description="IP地址", alias="ipAddress")
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user_agent: str = Field(..., description="浏览器信息", alias="userAgent")
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create_time: datetime = Field(..., description="创建时间", alias="createTime")
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class Config:
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from_attributes = True
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populate_by_name = True
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json_encoders = {
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# 自定义 datetime 类型的序列化格式
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datetime: lambda dt: dt.strftime('%Y-%m-%d %H:%M:%S')
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}
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```
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  `@field_validator`为Pydantic V2的验证器装饰器。
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  `class Config`为全局配置类，`from_attributes=True`表示允许从SQLAlchemy等ORM对象创建。
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# 三、服务层
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## 3.1 查询操作
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```python
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def query_blog_by_id(db: Session, blog_id: int) -> BlogResponse:
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check_blog_exist(db, blog_id)
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stmt = (select(
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Blog.id,
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Blog.title,
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Blog.top_value,
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Blog.is_great,
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BlogCategory.name.label("category"),
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Blog.summary,
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BlogContent.content,
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Blog.word_count,
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Blog.read_duration,
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func.count(BlogVisit.id).label("visitCount"),
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Blog.is_approved,
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Blog.create_time,
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Blog.update_time
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).where(Blog.id == blog_id)
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.outerjoin(BlogCategory, Blog.category_id == BlogCategory.id)
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.outerjoin(BlogContent, Blog.content_id == BlogContent.id)
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.outerjoin(BlogVisit, Blog.id == BlogVisit.blog_id))
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blog = db.execute(stmt).first()
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return BlogResponse.model_validate(blog)
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```
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  条件和分页查询
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```python
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def query_blog_by_condition(db: Session, blog_query: BlogQuery) -> List[BlogResponse]:
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stmt = get_query_blog_by_condition_stmt(blog_query)
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results = db.execute(stmt).fetchall()
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return [BlogResponse.model_validate(result) for result in results]
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def get_query_blog_by_condition_stmt(blog_query: BlogQuery):
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stmt = (select(
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Blog.id,
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Blog.title,
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Blog.top_value,
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Blog.is_great,
|
||
BlogCategory.name.label("category"),
|
||
Blog.summary,
|
||
BlogContent.content,
|
||
Blog.word_count,
|
||
Blog.read_duration,
|
||
func.count(BlogVisit.id).label("visitCount"),
|
||
Blog.is_approved,
|
||
Blog.create_time,
|
||
Blog.update_time
|
||
).where(Blog.is_approved == 1)
|
||
.outerjoin(BlogCategory, Blog.category_id == BlogCategory.id)
|
||
.outerjoin(BlogContent, Blog.content_id == BlogContent.id)
|
||
.outerjoin(BlogVisit, Blog.id == BlogVisit.blog_id)
|
||
.group_by(Blog.id))
|
||
|
||
conditions = []
|
||
|
||
if blog_query.category:
|
||
conditions.append(BlogCategory.name == blog_query.category)
|
||
|
||
if blog_query.title:
|
||
conditions.append(Blog.title.like(f"%{blog_query.title}%"))
|
||
|
||
if blog_query.year:
|
||
conditions.append(func.extract('year', Blog.create_time) == blog_query.year)
|
||
|
||
if conditions:
|
||
stmt = stmt.where(and_(*conditions))
|
||
|
||
stmt = stmt.order_by(desc(Blog.is_great), desc(Blog.update_time))
|
||
|
||
return stmt
|
||
|
||
|
||
def query_blog_by_condition_page(db: Session, blog_query: BlogQuery,
|
||
current_page: int = 1, page_size: int = 10) -> PageResult[BlogResponse]:
|
||
stmt = get_query_blog_by_condition_stmt(blog_query)
|
||
return paginate_query(db, stmt, current_page, page_size)
|
||
|
||
def paginate_query(db: Session, query, current_page: int = 1, page_size: int = 10) -> PageResult:
|
||
"""通用分页查询函数"""
|
||
# 计算总记录数
|
||
total = db.execute(select(func.count()).select_from(query.subquery())).scalar_one_or_none() or 0
|
||
|
||
# 计算总页数
|
||
total_pages = (total + page_size - 1) // page_size if page_size != 0 else 0
|
||
|
||
# 执行分页查询
|
||
results = db.execute(query.offset((current_page - 1) * page_size).limit(page_size)).all()
|
||
|
||
# 转换为字典列表
|
||
records = [row._asdict() if hasattr(row, "_asdict") else dict(row) for row in results]
|
||
|
||
return PageResult(
|
||
current=current_page,
|
||
size=page_size,
|
||
total=total,
|
||
pages=total_pages,
|
||
records=records
|
||
)
|
||
```
|
||
|
||
## 3.2 新增操作
|
||
```python
|
||
def add_blog(db: Session, blog: BlogCreate) -> bool:
|
||
word_count = get_word_count(blog.content)
|
||
|
||
db_blog = Blog(
|
||
title=blog.title,
|
||
top_value=blog.top_value,
|
||
is_great=blog.is_great,
|
||
category_id=add_blog_category(db, blog.category),
|
||
summary=get_blog_summary(blog.content),
|
||
word_count=word_count,
|
||
read_duration=get_read_duration(word_count),
|
||
is_approved=blog.is_approved
|
||
)
|
||
|
||
# 级联新增
|
||
db_blog.content = BlogContent(content=blog.content.encode('utf-8'))
|
||
|
||
db.add(db_blog)
|
||
db.commit()
|
||
db.refresh(db_blog)
|
||
|
||
return True
|
||
```
|
||
|
||
  这里的`db_blog.content`可以直接赋值`BlogContent`对象实现级联新增，不用传`content_id`。
|
||
>[!WARNING]
|
||
>这里的category和blog是多对一的关系，且需要一定的逻辑处理，不能直接赋值`BlogCategory`对象，否则每新增一条博客都会新增一个`category`。
|
||
|
||
## 3.3 更新操作
|
||
```python
|
||
def update_blog(db: Session, blog_id: int, blog: BlogUpdate) -> bool:
|
||
db_blog = check_blog_exist(db, blog_id)
|
||
|
||
db_blog.title = blog.title
|
||
db_blog.top_value = blog.topValue
|
||
db_blog.is_great = blog.isGreat
|
||
db_blog.category_id = update_blog_category(db, blog.category)
|
||
|
||
# 级联更新
|
||
db_blog.content = BlogContent(content=blog.content.encode('utf-8'))
|
||
|
||
word_count = get_word_count(blog.content)
|
||
db_blog.summary = get_blog_summary(blog.content),
|
||
db_blog.word_count = word_count
|
||
db_blog.read_duration = get_read_duration(word_count)
|
||
db_blog.is_approved = blog.isApproved
|
||
|
||
db.commit()
|
||
db.refresh(db_blog)
|
||
|
||
return True
|
||
```
|
||
|
||
## 3.4 删除操作
|
||
```python
|
||
def delete_blog(db: Session, blog_id: int) -> bool:
|
||
db_blog = check_blog_exist(db, blog_id)
|
||
|
||
# 级联删除
|
||
db.delete(db_blog)
|
||
db.commit()
|
||
|
||
return True
|
||
``` |