74 lines
3.5 KiB
Python
74 lines
3.5 KiB
Python
# File: backend/app/services/session_service.py (Update with DB)
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# Description: 管理会话数据的服务 (使用 SQLAlchemy)
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from typing import List, Optional
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from sqlalchemy.ext.asyncio import AsyncSession
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from sqlalchemy.future import select
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from sqlalchemy import delete as sqlalchemy_delete
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from app.db.models import SessionModel, AssistantModel # Import DB models
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from app.models.pydantic_models import SessionRead, SessionCreateRequest, SessionCreateResponse
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from datetime import datetime, timezone
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# Import ChatService for title generation (consider refactoring later)
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from app.services.chat_service import ChatService
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import app.core.config as Config
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chat_service_instance = ChatService(Config.GOOGLE_API_KEY)
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class SessionService:
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"""会话数据的 CRUD 及标题生成服务 (数据库版)"""
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async def create_session(self, db: AsyncSession, session_data: SessionCreateRequest) -> SessionCreateResponse:
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"""创建新会话并生成标题"""
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# 检查助手是否存在
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result = await db.execute(select(AssistantModel).filter(AssistantModel.id == session_data.assistant_id))
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assistant = result.scalars().first()
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if not assistant:
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raise ValueError("指定的助手不存在")
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# --- 调用 LLM 生成标题 ---
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try:
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title_prompt = f"根据以下用户第一条消息，为此对话生成一个简洁的标题（不超过10个字）:\n\n{session_data.first_message}"
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generated_title = await chat_service_instance.generate_text(title_prompt)
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except Exception as e:
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print(f"生成会话标题时出错: {e}")
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generated_title = f"关于 \"{session_data.first_message[:15]}...\"" # Fallback
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# --- 生成结束 ---
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db_session = SessionModel(
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title=generated_title,
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assistant_id=session_data.assistant_id
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# ID and created_at have defaults
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)
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db.add(db_session)
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await db.flush()
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await db.refresh(db_session)
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print(f"会话已创建 (DB): {db_session.id}")
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return SessionCreateResponse(
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id=db_session.id,
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title=db_session.title,
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assistant_id=db_session.assistant_id,
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created_at=db_session.created_at.isoformat() # Use datetime from DB model
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)
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async def get_sessions_by_assistant(self, db: AsyncSession, assistant_id: str) -> List[SessionRead]:
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"""获取指定助手的所有会话"""
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stmt = select(SessionModel).filter(SessionModel.assistant_id == assistant_id).order_by(SessionModel.updated_at.desc()) # Order by update time
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result = await db.execute(stmt)
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sessions = result.scalars().all()
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return [SessionRead.model_validate(s) for s in sessions]
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async def get_session(self, db: AsyncSession, session_id: str) -> Optional[SessionRead]:
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"""获取单个会话"""
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result = await db.execute(select(SessionModel).filter(SessionModel.id == session_id))
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session = result.scalars().first()
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return SessionRead.model_validate(session) if session else None
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async def delete_session(self, db: AsyncSession, session_id: str) -> bool:
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"""删除会话"""
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stmt = sqlalchemy_delete(SessionModel).where(SessionModel.id == session_id)
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result = await db.execute(stmt)
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if result.rowcount > 0:
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await db.flush()
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print(f"会话已删除 (DB): {session_id}")
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# Deletion of messages handled by cascade
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return True
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return False |