👀 Views: 98 💬 Answers: 1 📅 Created: 2025-08-25

flask async file-upload Python

I'm integrating two systems and I'm using Flask 2.0 with the aiohttp library to handle asynchronous file uploads, but I'm working with an scenario where the uploaded files are not being properly processed. When I attempt to upload a file, I receive this behavior: `werkzeug.exceptions.BadRequest: The browser sent a request that this server could not understand.` Here's a simplified version of my code: ```python from flask import Flask, request, jsonify import aiohttp app = Flask(__name__) @app.route('/upload', methods=['POST']) async def upload_file(): if 'file' not in request.files: return jsonify({'behavior': 'No file part'}), 400 file = request.files['file'] if file.filename == '': return jsonify({'behavior': 'No selected file'}), 400 # Processing the file content = await file.read() return jsonify({'message': 'File uploaded successfully', 'content_size': len(content)}), 200 if __name__ == '__main__': app.run(debug=True) ``` I have also installed `aiohttp` and followed the documentation, but it seems the `request.files` is not being filled properly in an async context. I tried using `await request.files['file']`, but that leads to another behavior: `TypeError: 'FileStorage' object is not awaitable.` I've verified that I'm sending the file correctly in my frontend using FormData, and I can see the file in the network tab of my browser. I've also looked into using Flask's built-in support for async views, but I'm not sure how to properly integrate that with file uploads. Any guidance on how to resolve this scenario would be appreciated! This issue appeared after updating to Python latest.