1. Add 登陆功能
2. 调整字体大小 3. 新增部分功能
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169
backend/app/infrastructure/session/redis_conversation_store.py
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169
backend/app/infrastructure/session/redis_conversation_store.py
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"""Redis-backed conversation store for persistent chat sessions.
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Sessions are stored as JSON strings under the key `session:{session_id}`.
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The Redis TTL is refreshed on every write so active sessions stay alive.
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On expiry, `get_session` returns None — callers should create a new session.
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"""
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from __future__ import annotations
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import json
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import time
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import uuid
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from typing import Any
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from loguru import logger
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from app.domain.conversation import ConversationMessage, ConversationSession, ConversationStore
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class RedisConversationStore(ConversationStore):
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"""Store conversation sessions in Redis with automatic TTL expiry.
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Each session is serialised as a JSON object at key ``session:{session_id}``.
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The TTL is reset on every write so sessions stay alive as long as they are active.
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"""
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# Prefix for all session keys to avoid collisions with other Redis consumers.
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_PREFIX = "session:"
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def __init__(self, *, redis_client: Any, timeout_seconds: int = 1800) -> None:
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"""Initialise the store with an existing Redis client and a TTL in seconds."""
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self._redis = redis_client
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self._ttl = timeout_seconds
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# ------------------------------------------------------------------
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# Internal helpers
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# ------------------------------------------------------------------
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def _key(self, session_id: str) -> str:
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"""Build the Redis key for a session."""
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return f"{self._PREFIX}{session_id}"
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def _serialise(self, session: ConversationSession) -> str:
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"""Serialise a ConversationSession to a JSON string."""
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return json.dumps(
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{
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"session_id": session.session_id,
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"created_at": session.created_at,
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"updated_at": session.updated_at,
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"metadata": session.metadata,
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"messages": [
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{
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"role": msg.role,
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"content": msg.content,
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"timestamp": msg.timestamp,
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"sources": msg.sources,
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}
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for msg in session.messages
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],
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},
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ensure_ascii=False,
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)
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def _deserialise(self, raw: bytes | str) -> ConversationSession:
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"""Deserialise a JSON string back into a ConversationSession."""
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data = json.loads(raw)
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messages = [
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ConversationMessage(
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role=m["role"],
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content=m["content"],
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timestamp=m["timestamp"],
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sources=m.get("sources", []),
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)
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for m in data.get("messages", [])
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]
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session = ConversationSession(
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session_id=data["session_id"],
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created_at=data.get("created_at", 0),
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updated_at=data.get("updated_at", 0),
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metadata=data.get("metadata", {}),
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)
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session.messages = messages
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return session
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def _save(self, session: ConversationSession) -> None:
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"""Persist a session to Redis and refresh its TTL."""
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self._redis.setex(self._key(session.session_id), self._ttl, self._serialise(session))
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# ------------------------------------------------------------------
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# ConversationStore protocol
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# ------------------------------------------------------------------
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def create_session(self, metadata: dict | None = None) -> ConversationSession:
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"""Create a new empty session and persist it immediately."""
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now = int(time.time())
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session = ConversationSession(
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session_id=str(uuid.uuid4())[:8],
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created_at=now,
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updated_at=now,
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metadata=metadata or {},
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)
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self._save(session)
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return session
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def get_session(self, session_id: str) -> ConversationSession | None:
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"""Return a session by ID, or None if it does not exist or has expired."""
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raw = self._redis.get(self._key(session_id))
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if raw is None:
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return None
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try:
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return self._deserialise(raw)
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except Exception:
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logger.warning("Failed to deserialise session: {}", session_id)
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return None
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def save_message(
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self,
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session_id: str,
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*,
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role: str,
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content: str,
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sources: list[dict] | None = None,
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) -> ConversationSession | None:
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"""Append a message to a session and refresh its TTL."""
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session = self.get_session(session_id)
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if session is None:
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return None
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session.messages.append(
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ConversationMessage(
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role=role,
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content=content,
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timestamp=int(time.time()),
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sources=sources or [],
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)
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)
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session.updated_at = int(time.time())
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self._save(session)
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return session
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def delete_session(self, session_id: str) -> bool:
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"""Delete a session. Returns True if it existed, False otherwise."""
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deleted = self._redis.delete(self._key(session_id))
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return bool(deleted)
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def list_sessions(self) -> list[dict]:
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"""Return summary dicts for all live sessions visible in this Redis DB.
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Note: KEYS is used for simplicity; replace with SCAN for large deployments.
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"""
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pattern = f"{self._PREFIX}*"
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keys = self._redis.keys(pattern)
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result = []
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for key in keys:
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raw = self._redis.get(key)
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if raw is None:
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continue
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try:
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data = json.loads(raw)
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result.append(
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{
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"session_id": data["session_id"],
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"message_count": len(data.get("messages", [])),
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"created_at": data.get("created_at", 0),
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"updated_at": data.get("updated_at", 0),
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}
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)
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except Exception:
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continue
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return result
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