655e039aad
原实现是 Canvas 画笔画板，与「文字白板/记事本」需求不符。重做为纯文本实时协作： - model：strokes JSON -> content TEXT + version INT（乐观锁）+ edit_count； schema/dao/service 同步重构，append_stroke/replace_strokes -> update_content。 - WS 协议：stroke -> edit（发完整文本，debounce 400ms）；init 下发 content/version。 update 帧广播给他人，cleared 广播给所有人。 - 前端：canvas -> textarea；收到远端 update 用最长公共前后缀算变更区间， 仅替换该区间并保留光标（区间前不动/后平移/内移末尾）；清空/复制文本按钮。 - schema.sql 更新 whiteboard 表 DDL；DB 旧表 DROP 重建（开发环境）。 - 测试脚本与 README 同步更新。
73 lines
2.4 KiB
Python
73 lines
2.4 KiB
Python
"""Whiteboard 的 DAO（文本记事本）。
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所有写操作均在该层 commit，service 不直接操作 session。
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get_or_create 用于「访问即新建」语义（路由 GET /api/wb/{id} 不存在则建）。
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"""
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from __future__ import annotations
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from sqlalchemy import func, select
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from sqlalchemy.orm import Session
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from ..models.whiteboard import Whiteboard
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class WhiteboardDAO:
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def __init__(self, db: Session) -> None:
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self.db = db
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def create(self, board: Whiteboard) -> Whiteboard:
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self.db.add(board)
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self.db.commit()
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self.db.refresh(board)
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return board
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def get(self, board_id: str) -> Whiteboard | None:
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stmt = select(Whiteboard).where(Whiteboard.board_id == board_id).limit(1)
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return self.db.scalars(stmt).first()
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def get_or_create(self, board_id: str) -> Whiteboard:
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"""存在则返回，否则新建空板。利用 unique 约束兜底并发首访。"""
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board = self.get(board_id)
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if board is not None:
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return board
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board = Whiteboard(board_id=board_id, content="", version=0, edit_count=0)
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try:
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return self.create(board)
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except Exception:
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# 并发下另一事务已插入：回滚后重新读
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self.db.rollback()
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return self.get(board_id) # type: ignore[return-value]
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def update_content(self, board_id: str, content: str) -> Whiteboard | None:
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"""整体替换文本内容，version +1、edit_count +1。"""
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board = self.get(board_id)
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if board is None:
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return None
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board.content = content
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board.version = (board.version or 0) + 1
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board.edit_count = (board.edit_count or 0) + 1
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self.db.commit()
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self.db.refresh(board)
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return board
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def list_all(self, limit: int = 100, offset: int = 0) -> list[Whiteboard]:
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stmt = (
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select(Whiteboard)
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.order_by(Whiteboard.updated_at.desc())
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.limit(limit)
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.offset(offset)
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)
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return list(self.db.scalars(stmt).all())
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def count(self) -> int:
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return self.db.scalar(select(func.count()).select_from(Whiteboard)) or 0
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def delete(self, board_id: str) -> bool:
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board = self.get(board_id)
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if board is None:
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return False
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self.db.delete(board)
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self.db.commit()
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return True
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