How does fastapi establish Http long connection?

[zhao004]

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Example Code

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
async def root():
    return {"message": "Hello World"}

# How to write Http long connection API?

Description

How to usefastapi to build a long HTTP connection and return data bit by bit like in the picture?

Operating System

Windows

Operating System Details

windows10

FastAPI Version

fastapi 0.111.0

Pydantic Version

pydantic 2.7.1

Python Version

Python 3.11.1

Additional Context

No response

[YuriiMotov]

Hi!

You can do it using StreamingResponse:

from fastapi import FastAPI
from fastapi.responses import StreamingResponse

app = FastAPI()


async def streamer():
    for i in range(10):
        yield b"some data"


@app.get("/")
async def main():
    return StreamingResponse(streamer())

In the example above you need to change streamer function to wait for the portion of data to send, send it (yield data_as_bytes) and wait for the next portion of data.

[zhao004]

Thank you very much, Mr. YuriiMotov