Scaffold V2 backend foundation

ai_knowledge_base_v2/apps/backend/app/api/chat.py

@@ -0,0 +1,94 @@
+from __future__ import annotations
+
+import json
+from collections.abc import Iterator
+
+from fastapi import APIRouter, Depends, Query
+from fastapi.responses import StreamingResponse
+from sqlalchemy.orm import Session
+
+from app.core.database import get_db
+from app.core.dependencies import get_current_user
+from app.core.responses import api_success
+from app.models.user import User
+from app.schemas.chat import (
+    ChatCompletionRequest,
+    ChatMessageRead,
+    ChatSessionRead,
+    CreateSessionResponse,
+    StopChatRequest,
+    UpdateSessionTitleRequest,
+)
+from app.services.chat_service import ChatService
+
+router = APIRouter()
+
+
+@router.post("/session")
+def create_session(db: Session = Depends(get_db), current_user: User = Depends(get_current_user)) -> dict:
+    session = ChatService.create_session(db, current_user)
+    return api_success(CreateSessionResponse(sessionId=session.id).model_dump())
+
+
+@router.get("/session/list")
+def list_sessions(db: Session = Depends(get_db), current_user: User = Depends(get_current_user)) -> dict:
+    sessions = ChatService.list_sessions(db, current_user)
+    return api_success([ChatSessionRead.model_validate(session).model_dump() for session in sessions])
+
+
+@router.get("/history")
+def history(
+    sessionId: int = Query(...),
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+) -> dict:
+    messages = ChatService.get_history(db, current_user, sessionId)
+    return api_success([ChatMessageRead.model_validate(message).model_dump(mode="json") for message in messages])
+
+
+@router.put("/session/title")
+def update_title(
+    payload: UpdateSessionTitleRequest,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+) -> dict:
+    session = ChatService.update_title(db, current_user, payload.sessionId, payload.title)
+    return api_success(ChatSessionRead.model_validate(session).model_dump())
+
+
+@router.delete("/session/{session_id}")
+def delete_session(
+    session_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+) -> dict:
+    ChatService.delete_session(db, current_user, session_id)
+    return api_success()
+
+
+@router.post("/completions")
+def completions(
+    payload: ChatCompletionRequest,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+) -> StreamingResponse:
+    answer = ChatService.create_mock_answer(db, current_user, payload.sessionId, payload.message)
+    return StreamingResponse(_sse_chunks(answer), media_type="text/event-stream")
+
+
+@router.post("/stop")
+def stop(
+    payload: StopChatRequest,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+) -> dict:
+    ChatService.stop_generation(db, current_user, payload.sessionId)
+    return api_success()
+
+
+def _sse_chunks(answer: str) -> Iterator[str]:
+    chunk_size = 12
+    for index in range(0, len(answer), chunk_size):
+        chunk = answer[index : index + chunk_size]
+        yield f"data: {json.dumps({'content': chunk}, ensure_ascii=False)}\n\n"
+    yield "data: [DONE]\n\n"