108 lines
4.2 KiB
Python
108 lines
4.2 KiB
Python
import json
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from channels.generic.websocket import AsyncJsonWebsocketConsumer
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from channels.db import database_sync_to_async
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from django.core.serializers.json import DjangoJSONEncoder
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from .basic import execute_data_query
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class DataConsumer(AsyncJsonWebsocketConsumer):
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async def encode_json(self, content):
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"""
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Encode the given content as JSON, using Django's encoder
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to handle dates, decimals, etc.
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"""
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return json.dumps(content, cls=DjangoJSONEncoder)
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async def connect(self):
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self.subscribed_groups = set()
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self.subscription_params = {} # e.g., {'Product': {'filter': '...', 'values': '...'}}
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await self.accept()
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async def disconnect(self, close_code):
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for group_name in self.subscribed_groups:
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await self.channel_layer.group_discard(group_name, self.channel_name)
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async def receive_json(self, content):
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action = content.get("action")
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if action == "subscribe":
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await self.handle_subscribe(content.get("payload", {}), content.get("request_id"))
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async def handle_subscribe(self, payload, request_id):
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model_name = payload.get("name")
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params = payload.get("params", {})
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if not model_name:
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await self.send_json({"type": "error", "request_id": request_id, "message": "Model name is required."})
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return
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# Store subscription params for this client
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self.subscription_params[model_name] = params
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# Run the initial data query
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data = await database_sync_to_async(execute_data_query)(model_name, params)
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# Send the initial result back to the client
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await self.send_json({
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"type": "subscription_response",
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"request_id": request_id,
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"data": data
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})
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# Join the group using a lowercase model name to match the signal
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group_name = f"model_{model_name.lower()}_updates"
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if group_name not in self.subscribed_groups:
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await self.channel_layer.group_add(group_name, self.channel_name)
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self.subscribed_groups.add(group_name)
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async def realtime_update(self, event):
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# Move imports inside the method to prevent AppRegistryNotReady error on startup
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import ast
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from django.db.models import Q
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from .views import get_serializer
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payload = event["payload"]
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record = payload["record"]
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model_name_lower = payload["name"]
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model_name_capitalized = model_name_lower.capitalize()
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# 1. Get this client's subscription parameters for the specific model
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client_params = self.subscription_params.get(model_name_capitalized)
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if not client_params:
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return # This client is not subscribed to this model.
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# 2. Check if the updated record matches the client's filter
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filter_str = client_params.get('filter')
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if filter_str:
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try:
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Model, _ = get_serializer(model_name_lower)
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if not Model:
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return
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filter_q = Q()
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filter_dict = ast.literal_eval(filter_str)
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for key, value in filter_dict.items():
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filter_q.add(Q(**{key: value}), Q.AND)
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matches = await database_sync_to_async(
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Model.objects.filter(pk=record["id"]).filter(filter_q).exists
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)()
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if not matches:
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return # Record does not match the client's filter, so don't send.
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except Exception:
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return # Fail silently if filter is invalid or DB check fails.
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# 3. Create a tailored payload, respecting the 'values' parameter
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payload_for_client = payload.copy()
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values_str = client_params.get('values')
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if values_str:
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requested_values = values_str.split(',')
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# The record from the signal contains all fields. Filter it down.
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filtered_record = {key: record.get(key) for key in requested_values if key in record}
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payload_for_client['record'] = filtered_record
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# 4. Send the final, tailored payload to the client
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await self.send_json({
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"type": "realtime_update",
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"payload": payload_for_client
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})
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