Files
ds-chat/backend/app/services/message_service.py
T
ksmithandClaude Sonnet 5 c78d7454b6 Add generic file attachments to chat messages
Messages can now carry an arbitrary file (MessageFile), parallel to the
existing MessageImage feature rather than a refactor of it. Files serve
with Content-Disposition: attachment to force a download and prevent an
uploaded HTML/SVG from executing same-origin. No content-type allowlist,
same 8MB cap as images for now (a separate size-limit redesign is tracked
as its own issue).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-15 08:02:55 -06:00

117 lines
3.5 KiB
Python

import uuid
from collections import defaultdict
from datetime import datetime, timezone
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload
from app.models import Message, MessageReaction
from app.schemas.message import ReactionSummary
class MessageNotFoundError(Exception):
pass
class NotMessageAuthorError(Exception):
pass
async def create_message(
db: AsyncSession,
room_id: uuid.UUID,
user_id: uuid.UUID,
content: str | None = None,
image_id: uuid.UUID | None = None,
file_id: uuid.UUID | None = None,
) -> Message:
message = Message(
room_id=room_id, user_id=user_id, content=content, image_id=image_id, file_id=file_id
)
db.add(message)
await db.commit()
await db.refresh(message)
return message
async def edit_message(
db: AsyncSession, message_id: uuid.UUID, editor_id: uuid.UUID, content: str
) -> Message:
message = await db.get(Message, message_id)
if message is None:
raise MessageNotFoundError()
if message.user_id != editor_id:
raise NotMessageAuthorError()
message.content = content
message.edited_at = datetime.now(timezone.utc)
await db.commit()
await db.refresh(message)
return message
async def list_recent_messages(
db: AsyncSession, room_id: uuid.UUID, limit: int = 50
) -> list[Message]:
result = await db.execute(
select(Message)
.where(Message.room_id == room_id)
.options(selectinload(Message.user), selectinload(Message.file))
.order_by(Message.created_at.desc())
.limit(limit)
)
messages = list(result.scalars().all())
messages.reverse()
return messages
async def get_reactions_for_messages(
db: AsyncSession, message_ids: list[uuid.UUID]
) -> dict[uuid.UUID, list[ReactionSummary]]:
if not message_ids:
return {}
result = await db.execute(
select(MessageReaction)
.where(MessageReaction.message_id.in_(message_ids))
.order_by(MessageReaction.created_at)
)
# Grouped in Python rather than a GROUP BY/array_agg query -- the row
# count per room-history page is small, and this keeps the ordering
# (first-reacted emoji first, first-reacted user first within it)
# trivial instead of relying on Postgres-specific aggregate ordering.
by_message: dict[uuid.UUID, dict[str, list[str]]] = defaultdict(dict)
for reaction in result.scalars().all():
emoji_map = by_message[reaction.message_id]
emoji_map.setdefault(reaction.emoji, []).append(str(reaction.user_id))
return {
message_id: [
ReactionSummary(emoji=emoji, count=len(user_ids), user_ids=user_ids)
for emoji, user_ids in emoji_map.items()
]
for message_id, emoji_map in by_message.items()
}
async def toggle_reaction(
db: AsyncSession, message_id: uuid.UUID, user_id: uuid.UUID, emoji: str
) -> list[ReactionSummary]:
result = await db.execute(
select(MessageReaction).where(
MessageReaction.message_id == message_id,
MessageReaction.user_id == user_id,
MessageReaction.emoji == emoji,
)
)
existing = result.scalar_one_or_none()
if existing is not None:
await db.delete(existing)
else:
db.add(MessageReaction(message_id=message_id, user_id=user_id, emoji=emoji))
await db.commit()
reactions = await get_reactions_for_messages(db, [message_id])
return reactions.get(message_id, [])