How can I POST data in real time using FastAPI?

Question

I built a simple demo project using FastAPI. I would like to POST data to the server in real time (maybe 30fps ).

 # in client while True:.... res = requests.post(URL, files={'input_data': input_data})....

But, I get the following error:

(MaxRetryError: HTTPConnectionPool(host='~~', port=8000): Max retries exceeded with url)

I think it is caused due to the multiple requests, but I would like to perform requests in real time. How can I do?

Answer 1

As noted by @MatsLindh in the comments, you should rather use a more suitable protocol - such asWebSockets - than HTTP for such a task. FastAPI/Starlette supports sending and receiving data on a websocket (see the documentation here and here ). Below is an example of using websockets to send video frames from a client to a server (assuming this is your task from your comment on 30fps - however, the same appproach could be applied to sending other types of data). OpenCV is used to capture the frames and websockets library is used to connect to the WebSocket server.

server.py

 from fastapi import FastAPI, WebSocket, WebSocketDisconnect import cv2 import numpy as np app = FastAPI() @app.websocket("/ws") async def websocket_endpoint(websocket: WebSocket): # listen for connections await websocket.accept() #count = 1 try: while True: contents = await websocket.receive_bytes() arr = np.frombuffer(contents, np.uint8) frame = cv2.imdecode(arr, cv2.IMREAD_UNCHANGED) cv2.imshow('frame', frame) cv2.waitKey(1) #cv2.imwrite("frame%d.png" % count, frame) #count += 1 except WebSocketDisconnect: cv2.destroyWindow("frame") print("Client disconnected")

client.py

 import websockets import asyncio import cv2 camera = cv2.VideoCapture(0, cv2.CAP_DSHOW) async def main(): # Connect to the server async with websockets.connect('ws://localhost:8000/ws') as ws: while True: success, frame = camera.read() if not success: break else: ret, buffer = cv2.imencode('.png', frame) await ws.send(buffer.tobytes()) # Start the connection asyncio.run(main())