feat: persist photos and enrich conversation history

backend/routes/conversations.py

@@ -1,15 +1,20 @@
 """对话历史查询 API。"""
 
-from db.models import ConversationMessage, ConversationSession
+import asyncio
+
+from db.models import ConversationArtifact, ConversationMessage, ConversationSession
 from db.session import get_session
-from fastapi import APIRouter, Depends, HTTPException, Query
+from fastapi import APIRouter, Depends, HTTPException, Query, Response
+from loguru import logger
 from schemas import (
+    ConversationArtifactOut,
     ConversationDetailOut,
     ConversationListOut,
     ConversationMessageOut,
     ConversationOut,
 )
 from services.auth import require_admin
+from services.object_storage import delete_object, get_object, key_from_storage_uri
 from sqlalchemy import func, or_, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -100,6 +105,17 @@ async def get_conversation(
             .order_by(ConversationMessage.sequence)
         )
     ).scalars().all()
+    artifacts = (
+        await session.execute(
+            select(ConversationArtifact)
+            .where(ConversationArtifact.session_id == conversation_id)
+            .order_by(ConversationArtifact.created_at)
+        )
+    ).scalars().all()
+    artifacts_by_message: dict[str, list[ConversationArtifact]] = {}
+    for artifact in artifacts:
+        if artifact.message_id:
+            artifacts_by_message.setdefault(artifact.message_id, []).append(artifact)
     return ConversationDetailOut(
         **_session_out(conversation).model_dump(),
         extra=conversation.extra or {},
@@ -112,12 +128,52 @@ async def get_conversation(
                 content=message.content,
                 occurred_at=message.occurred_at,
                 extra=message.extra or {},
+                artifacts=[
+                    ConversationArtifactOut(
+                        id=artifact.id,
+                        kind=artifact.kind,
+                        content_url=(
+                            f"/api/conversations/{conversation_id}/artifacts/"
+                            f"{artifact.id}/content"
+                        ),
+                        mime_type=artifact.mime_type,
+                        size_bytes=artifact.size_bytes,
+                        duration_ms=artifact.duration_ms,
+                        extra=artifact.extra or {},
+                    )
+                    for artifact in artifacts_by_message.get(message.id, [])
+                ],
             )
             for message in messages
         ],
     )
 
 
+@router.get("/{conversation_id}/artifacts/{artifact_id}/content")
+async def get_conversation_artifact(
+    conversation_id: str,
+    artifact_id: str,
+    session: AsyncSession = Depends(get_session),
+):
+    artifact = await session.get(ConversationArtifact, artifact_id)
+    if not artifact or artifact.session_id != conversation_id:
+        raise HTTPException(404, "会话附件不存在")
+    try:
+        key = key_from_storage_uri(artifact.storage_uri)
+        data = await asyncio.to_thread(get_object, key)
+    except Exception as exc:
+        logger.warning(f"读取会话附件失败: {artifact_id}: {exc}")
+        raise HTTPException(404, "会话附件不可用") from exc
+    return Response(
+        content=data,
+        media_type=artifact.mime_type or "application/octet-stream",
+        headers={
+            "Cache-Control": "private, max-age=300",
+            "Content-Disposition": f'inline; filename="{artifact.id}"',
+        },
+    )
+
+
 @router.delete("/{conversation_id}")
 async def delete_conversation(
     conversation_id: str,
@@ -126,6 +182,19 @@ async def delete_conversation(
     conversation = await session.get(ConversationSession, conversation_id)
     if not conversation:
         raise HTTPException(404, "对话记录不存在")
+    storage_uris = (
+        await session.execute(
+            select(ConversationArtifact.storage_uri).where(
+                ConversationArtifact.session_id == conversation_id
+            )
+        )
+    ).scalars().all()
     await session.delete(conversation)
     await session.commit()
+    for storage_uri in storage_uris:
+        try:
+            key = key_from_storage_uri(storage_uri)
+            await asyncio.to_thread(delete_object, key)
+        except Exception as exc:
+            logger.warning(f"清理已删除会话的附件失败: {storage_uri}: {exc}")
     return {"ok": True}