initial_commit

2026-06-01 20:16:53 +09:00
commit 903d34761c
31 changed files with 1123 additions and 0 deletions
@@ -0,0 +1,91 @@
+import uuid
+from datetime import datetime, timezone
+from fastapi import APIRouter, Depends, HTTPException
+from fastapi.responses import StreamingResponse
+from pydantic import BaseModel
+from sqlalchemy.orm import Session as DBSession
+
+from app.db.database import get_db
+from app.db.models import Session, Message
+from app.core import memory as mem
+from app.core import llm
+from app.core.config import DEFAULT_MODEL
+
+router = APIRouter(prefix="/chat", tags=["chat"])
+
+
+class ChatRequest(BaseModel):
+    session_id: str | None = None
+    message: str
+    model: str | None = None
+
+
+class SessionResponse(BaseModel):
+    id: str
+    title: str
+    model: str
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+@router.get("/sessions", response_model=list[SessionResponse])
+def list_sessions(db: DBSession = Depends(get_db)):
+    return db.query(Session).order_by(Session.updated_at.desc()).all()
+
+
+@router.delete("/sessions/{session_id}", status_code=204)
+def delete_session(session_id: str, db: DBSession = Depends(get_db)):
+    session = db.get(Session, session_id)
+    if not session:
+        raise HTTPException(status_code=404, detail="Session not found")
+    db.delete(session)
+    db.commit()
+
+
+@router.post("/stream")
+async def stream_chat(req: ChatRequest, db: DBSession = Depends(get_db)):
+    # セッション取得 or 新規作成
+    if req.session_id:
+        session = db.get(Session, req.session_id)
+        if not session:
+            raise HTTPException(status_code=404, detail="Session not found")
+    else:
+        session = Session(
+            id=str(uuid.uuid4()),
+            title=req.message[:40],
+            model=req.model or DEFAULT_MODEL,
+        )
+        db.add(session)
+        db.commit()
+
+    # ユーザーメッセージを保存
+    user_msg = Message(session_id=session.id, role="user", content=req.message)
+    db.add(user_msg)
+    db.commit()
+
+    context = mem.get_context_messages(db, session.id)
+
+    async def generate():
+        # セッションIDをまず返す（新規セッション時にフロントへ通知）
+        yield f"data: {{\"type\":\"session_id\",\"value\":\"{session.id}\"}}\n\n"
+
+        full_response = []
+        async for chunk in llm.stream_chat(context, model=req.model or session.model):
+            full_response.append(chunk)
+            escaped = chunk.replace('"', '\\"').replace('\n', '\\n')
+            yield f"data: {{\"type\":\"chunk\",\"value\":\"{escaped}\"}}\n\n"
+
+        # アシスタントメッセージを保存
+        assistant_content = "".join(full_response)
+        db.add(Message(session_id=session.id, role="assistant", content=assistant_content))
+        session.updated_at = datetime.now(timezone.utc)
+        db.commit()
+
+        # メモリ要約チェック
+        await mem.maybe_summarize(db, session)
+
+        yield "data: {\"type\":\"done\"}\n\n"
+
+    return StreamingResponse(generate(), media_type="text/event-stream")
@@ -0,0 +1,33 @@
+from fastapi import APIRouter, Depends, HTTPException
+from pydantic import BaseModel
+from datetime import datetime
+from sqlalchemy.orm import Session as DBSession
+
+from app.db.database import get_db
+from app.db.models import Memory
+
+router = APIRouter(prefix="/memory", tags=["memory"])
+
+
+class MemoryResponse(BaseModel):
+    id: int
+    session_id: str
+    summary: str
+    created_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+@router.get("/{session_id}", response_model=list[MemoryResponse])
+def get_memories(session_id: str, db: DBSession = Depends(get_db)):
+    return db.query(Memory).filter(Memory.session_id == session_id).order_by(Memory.created_at).all()
+
+
+@router.delete("/{memory_id}", status_code=204)
+def delete_memory(memory_id: int, db: DBSession = Depends(get_db)):
+    memory = db.get(Memory, memory_id)
+    if not memory:
+        raise HTTPException(status_code=404, detail="Memory not found")
+    db.delete(memory)
+    db.commit()
@@ -0,0 +1,9 @@
+from dotenv import load_dotenv
+import os
+
+load_dotenv()
+
+DATABASE_URL: str = os.getenv("DATABASE_URL", "sqlite:///./playchat.db")
+DEFAULT_MODEL: str = os.getenv("DEFAULT_MODEL", "gpt-4o")
+MEMORY_SUMMARIZE_THRESHOLD: int = int(os.getenv("MEMORY_SUMMARIZE_THRESHOLD", "20"))
+CORS_ORIGINS: list[str] = os.getenv("CORS_ORIGINS", "http://localhost:5173").split(",")
@@ -0,0 +1,29 @@
+from typing import AsyncIterator
+import litellm
+from app.core.config import DEFAULT_MODEL
+
+litellm.drop_params = True
+
+
+async def stream_chat(
+    messages: list[dict],
+    model: str | None = None,
+) -> AsyncIterator[str]:
+    response = await litellm.acompletion(
+        model=model or DEFAULT_MODEL,
+        messages=messages,
+        stream=True,
+    )
+    async for chunk in response:
+        delta = chunk.choices[0].delta.content
+        if delta:
+            yield delta
+
+
+async def complete(messages: list[dict], model: str | None = None) -> str:
+    response = await litellm.acompletion(
+        model=model or DEFAULT_MODEL,
+        messages=messages,
+        stream=False,
+    )
+    return response.choices[0].message.content or ""
@@ -0,0 +1,44 @@
+from sqlalchemy.orm import Session as DBSession
+from app.db.models import Memory, Message, Session
+from app.core.config import MEMORY_SUMMARIZE_THRESHOLD
+from app.core import llm
+
+
+def get_context_messages(db: DBSession, session_id: str) -> list[dict]:
+    """短期メモリ（最近のメッセージ）と長期メモリ（要約）を結合してコンテキストを返す。"""
+    memories = db.query(Memory).filter(Memory.session_id == session_id).order_by(Memory.created_at).all()
+    messages = db.query(Message).filter(Message.session_id == session_id).order_by(Message.created_at).all()
+
+    context: list[dict] = []
+
+    if memories:
+        combined_summary = "\n\n".join(m.summary for m in memories)
+        context.append({
+            "role": "system",
+            "content": f"以下はこの会話の過去の要約です:\n\n{combined_summary}",
+        })
+
+    context.extend({"role": m.role, "content": m.content} for m in messages)
+    return context
+
+
+async def maybe_summarize(db: DBSession, session: Session) -> None:
+    """メッセージ数が閾値を超えたら古いメッセージを要約してMemoryに保存し、元メッセージを削除する。"""
+    messages = db.query(Message).filter(Message.session_id == session.id).order_by(Message.created_at).all()
+    if len(messages) < MEMORY_SUMMARIZE_THRESHOLD:
+        return
+
+    # 古いメッセージ（閾値の半分）を要約対象にする
+    half = MEMORY_SUMMARIZE_THRESHOLD // 2
+    to_summarize = messages[:half]
+
+    summary_prompt = [
+        {"role": "system", "content": "以下の会話を簡潔に要約してください。重要な事実・決定・文脈を保持してください。"},
+        *[{"role": m.role, "content": m.content} for m in to_summarize],
+    ]
+    summary_text = await llm.complete(summary_prompt)
+
+    db.add(Memory(session_id=session.id, summary=summary_text))
+    for msg in to_summarize:
+        db.delete(msg)
+    db.commit()
@@ -0,0 +1,23 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker, DeclarativeBase
+from app.core.config import DATABASE_URL
+
+engine = create_engine(DATABASE_URL, connect_args={"check_same_thread": False})
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+def init_db():
+    from app.db import models  # noqa: F401
+    Base.metadata.create_all(bind=engine)
@@ -0,0 +1,41 @@
+from datetime import datetime, timezone
+from sqlalchemy import String, Text, DateTime, ForeignKey, Integer
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from app.db.database import Base
+
+
+class Session(Base):
+    __tablename__ = "sessions"
+
+    id: Mapped[str] = mapped_column(String, primary_key=True)
+    title: Mapped[str] = mapped_column(String, default="New Chat")
+    model: Mapped[str] = mapped_column(String, default="")
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=lambda: datetime.now(timezone.utc))
+    updated_at: Mapped[datetime] = mapped_column(DateTime, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc))
+
+    messages: Mapped[list["Message"]] = relationship(back_populates="session", cascade="all, delete-orphan", order_by="Message.created_at")
+    memories: Mapped[list["Memory"]] = relationship(back_populates="session", cascade="all, delete-orphan")
+
+
+class Message(Base):
+    __tablename__ = "messages"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    session_id: Mapped[str] = mapped_column(ForeignKey("sessions.id", ondelete="CASCADE"))
+    role: Mapped[str] = mapped_column(String)  # "user" | "assistant" | "system"
+    content: Mapped[str] = mapped_column(Text)
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=lambda: datetime.now(timezone.utc))
+
+    session: Mapped["Session"] = relationship(back_populates="messages")
+
+
+class Memory(Base):
+    __tablename__ = "memories"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    session_id: Mapped[str] = mapped_column(ForeignKey("sessions.id", ondelete="CASCADE"))
+    summary: Mapped[str] = mapped_column(Text)
+    embedding_json: Mapped[str | None] = mapped_column(Text, nullable=True)  # 将来のベクトル検索用
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=lambda: datetime.now(timezone.utc))
+
+    session: Mapped["Session"] = relationship(back_populates="memories")
@@ -0,0 +1,30 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.core.config import CORS_ORIGINS
+from app.db.database import init_db
+from app.api import chat, memory
+
+app = FastAPI(title="PlayChat API", version="0.1.0")
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=CORS_ORIGINS,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+
+@app.on_event("startup")
+def on_startup():
+    init_db()
+
+
+app.include_router(chat.router)
+app.include_router(memory.router)
+
+
+@app.get("/health")
+def health():
+    return {"status": "ok"}