👀 Views: 458 💬 Answers: 1 📅 Created: 2025-10-17

Django Async Middleware Python

Currently developing a migration plan for a Django application that’s been running on version 2.2... The staging environment has just been set up with Django 3.x to prepare for the upgrade. One of the features that we heavily leverage is asynchronous views, but I'm running into hurdles integrating them with some of our existing middleware, especially ones that rely on synchronous execution. For instance, I've implemented an async view as follows: ```python from django.http import JsonResponse from asgiref.sync import sync_to_async async def async_view(request): data = await fetch_data_async() return JsonResponse(data) ``` When I attempt to call this view, I get a `RuntimeError: You cannot call this from an async context - use an async method instead`. The middleware that’s throwing this error looks like this: ```python class SyncMiddleware: def __init__(self, get_response): self.get_response = get_response def __call__(self, request): # Some synchronous processing response = self.get_response(request) return response ``` I've tried modifying `SyncMiddleware` to allow for async processing using `async def __call__(self, request)`, but I’m not sure of the correct approach to handle the request lifecycle here, especially considering that it also needs to maintain compatibility with the synchronous views in our application. Also, our team has been using `asgiref` to implement some async functionality before this migration. Should I refactor all middleware to be async-aware, or is there a pattern that allows for some middleware to remain synchronous? Any insights on how to approach this situation would be greatly appreciated. Additionally, if anyone has encountered similar migration issues with Django 3.x, I’d love to hear what strategies you employed to facilitate a smooth transition. The stack includes Python and several other technologies. Could this be a known issue?