alex
757140ec70
Implement a full chat-based travel agent using LiteLLM for multi-provider LLM support (OpenAI, Anthropic, Gemini, Ollama, Groq, Mistral, etc.). Backend: - New 'chat' Django app with ChatConversation and ChatMessage models - Streaming SSE endpoint via StreamingHttpResponse - 5 agent tools: search_places, list_trips, get_trip_details, add_to_itinerary, get_weather - LiteLLM client wrapper with per-user API key retrieval - System prompt with user preference context injection Frontend: - New /chat route with full-page chat UI (DaisyUI + Tailwind) - Collapsible conversation sidebar with CRUD - SSE streaming response display with tool call visualization - Provider selector dropdown - SSE proxy fix to stream text/event-stream without buffering - Navbar link and i18n keys
261 lines
9.7 KiB
Python
261 lines
9.7 KiB
Python
import asyncio
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import json
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from asgiref.sync import sync_to_async
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from django.http import StreamingHttpResponse
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from rest_framework import status, viewsets
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from rest_framework.decorators import action
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from rest_framework.permissions import IsAuthenticated
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from rest_framework.response import Response
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from .agent_tools import AGENT_TOOLS, execute_tool, serialize_tool_result
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from .llm_client import get_system_prompt, stream_chat_completion
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from .models import ChatConversation, ChatMessage
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from .serializers import ChatConversationSerializer
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class ChatViewSet(viewsets.ModelViewSet):
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serializer_class = ChatConversationSerializer
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permission_classes = [IsAuthenticated]
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def get_queryset(self):
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return ChatConversation.objects.filter(user=self.request.user).prefetch_related(
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"messages"
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)
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def list(self, request, *args, **kwargs):
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conversations = self.get_queryset().only("id", "title", "updated_at")
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data = [
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{
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"id": str(conversation.id),
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"title": conversation.title,
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"updated_at": conversation.updated_at,
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}
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for conversation in conversations
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]
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return Response(data)
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def create(self, request, *args, **kwargs):
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conversation = ChatConversation.objects.create(
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user=request.user,
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title=(request.data.get("title") or "").strip(),
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)
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serializer = self.get_serializer(conversation)
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return Response(serializer.data, status=status.HTTP_201_CREATED)
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def _build_llm_messages(self, conversation, user):
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messages = [{"role": "system", "content": get_system_prompt(user)}]
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for message in conversation.messages.all().order_by("created_at"):
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payload = {
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"role": message.role,
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"content": message.content,
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}
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if message.role == "assistant" and message.tool_calls:
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payload["tool_calls"] = message.tool_calls
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if message.role == "tool":
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payload["tool_call_id"] = message.tool_call_id
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payload["name"] = message.name
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messages.append(payload)
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return messages
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def _async_to_sync_generator(self, async_gen):
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loop = asyncio.new_event_loop()
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try:
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while True:
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try:
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yield loop.run_until_complete(async_gen.__anext__())
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except StopAsyncIteration:
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break
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finally:
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loop.run_until_complete(loop.shutdown_asyncgens())
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loop.close()
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@staticmethod
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def _merge_tool_call_delta(accumulator, tool_calls_delta):
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for idx, tool_call in enumerate(tool_calls_delta or []):
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while len(accumulator) <= idx:
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accumulator.append(
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{
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"id": None,
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"type": "function",
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"function": {"name": "", "arguments": ""},
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}
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)
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current = accumulator[idx]
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if tool_call.get("id"):
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current["id"] = tool_call.get("id")
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if tool_call.get("type"):
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current["type"] = tool_call.get("type")
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function_data = tool_call.get("function") or {}
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if function_data.get("name"):
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current["function"]["name"] = function_data.get("name")
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if function_data.get("arguments"):
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current["function"]["arguments"] += function_data.get("arguments")
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@action(detail=True, methods=["post"])
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def send_message(self, request, pk=None):
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conversation = self.get_object()
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user_content = (request.data.get("message") or "").strip()
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if not user_content:
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return Response(
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{"error": "message is required"},
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status=status.HTTP_400_BAD_REQUEST,
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)
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provider = (request.data.get("provider") or "openai").strip().lower()
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ChatMessage.objects.create(
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conversation=conversation,
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role="user",
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content=user_content,
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)
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conversation.save(update_fields=["updated_at"])
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if not conversation.title:
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conversation.title = user_content[:120]
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conversation.save(update_fields=["title", "updated_at"])
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llm_messages = self._build_llm_messages(conversation, request.user)
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async def event_stream():
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current_messages = list(llm_messages)
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encountered_error = False
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while True:
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content_chunks = []
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tool_calls_accumulator = []
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async for chunk in stream_chat_completion(
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request.user,
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current_messages,
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provider,
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tools=AGENT_TOOLS,
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):
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if not chunk.startswith("data: "):
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yield chunk
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continue
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payload = chunk[len("data: ") :].strip()
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if payload == "[DONE]":
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continue
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yield chunk
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try:
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data = json.loads(payload)
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except json.JSONDecodeError:
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continue
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if data.get("error"):
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encountered_error = True
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break
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if data.get("content"):
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content_chunks.append(data["content"])
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if data.get("tool_calls"):
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self._merge_tool_call_delta(
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tool_calls_accumulator,
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data["tool_calls"],
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)
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if encountered_error:
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break
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assistant_content = "".join(content_chunks)
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if tool_calls_accumulator:
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assistant_with_tools = {
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"role": "assistant",
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"content": assistant_content,
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"tool_calls": tool_calls_accumulator,
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}
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current_messages.append(assistant_with_tools)
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await sync_to_async(
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ChatMessage.objects.create, thread_sensitive=True
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)(
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conversation=conversation,
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role="assistant",
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content=assistant_content,
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tool_calls=tool_calls_accumulator,
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)
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await sync_to_async(conversation.save, thread_sensitive=True)(
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update_fields=["updated_at"]
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)
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for tool_call in tool_calls_accumulator:
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function_payload = tool_call.get("function") or {}
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function_name = function_payload.get("name") or ""
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raw_arguments = function_payload.get("arguments") or "{}"
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try:
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arguments = json.loads(raw_arguments)
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except json.JSONDecodeError:
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arguments = {}
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if not isinstance(arguments, dict):
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arguments = {}
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result = await sync_to_async(
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execute_tool, thread_sensitive=True
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)(
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function_name,
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request.user,
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**arguments,
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)
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result_content = serialize_tool_result(result)
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current_messages.append(
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{
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"role": "tool",
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"tool_call_id": tool_call.get("id"),
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"name": function_name,
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"content": result_content,
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}
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)
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await sync_to_async(
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ChatMessage.objects.create, thread_sensitive=True
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)(
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conversation=conversation,
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role="tool",
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content=result_content,
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tool_call_id=tool_call.get("id"),
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name=function_name,
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)
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await sync_to_async(conversation.save, thread_sensitive=True)(
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update_fields=["updated_at"]
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)
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tool_event = {
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"tool_result": {
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"tool_call_id": tool_call.get("id"),
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"name": function_name,
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"result": result,
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}
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}
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yield f"data: {json.dumps(tool_event)}\n\n"
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continue
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await sync_to_async(ChatMessage.objects.create, thread_sensitive=True)(
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conversation=conversation,
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role="assistant",
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content=assistant_content,
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)
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await sync_to_async(conversation.save, thread_sensitive=True)(
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update_fields=["updated_at"]
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)
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yield "data: [DONE]\n\n"
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break
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response = StreamingHttpResponse(
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streaming_content=self._async_to_sync_generator(event_stream()),
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content_type="text/event-stream",
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)
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response["Cache-Control"] = "no-cache"
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response["X-Accel-Buffering"] = "no"
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return response
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