[QUESTION] Streaming Response

Hi,

I am trying to port some aiohttp code to FastAPI.

I have a simple (redis) pub-sub system with a producer and consumers. A client connect to a http endpoint then is subscribeb to a channel finally when a producer publishes a message in this channel it gets sent to the connected client as part of the response’s body.

aiohttp provides StreamResponse you can use it the following way:

async def stream_handler(request):
    response = web.StreamResponse()
    await response.prepare(request)
    (channel,) = await redis.subscribe("foobar")
    while True:
        message = await channel.get()
        await response.write(message)

Below is how I tried to port that to FastAPI

from fastapi import FastAPI
from fastapi.responses import StreamingResponse
import aioredis

app = FastAPI()

async def messages_from_redis(channel):
        while True:
            message = await channel.get()
            if message:
                yield message
                print(message)

@app.get("/")
async def main():
    redis = await aioredis.create_redis_pool("redis://localhost:6379/")
    (channel,) = await redis.subscribe("foobar")
    return StreamingResponse(messages_from_redis(channel))

I am not even sure I am using the StreamingResponse class the right way. It would be really appreciated if someone could help me.

[tiangolo]

Thanks for the help @Mause! 🚀

Thanks for coming back to close the issue @mekza 🍰

Sorry for the long delay! 🙈 I wanted to personally address each issue/PR and they piled up through time, but now I’m checking each one in order.

[mekza]

@Mause omg! Thanks for the hint. My http client was buffering…