FastApi proxy endpoint

app.py

# adapted from https://github.com/fastapi/fastapi/issues/1788
from fastapi import FastAPI
from starlette.requests import Request
from starlette.responses import StreamingResponse
from starlette.background import BackgroundTask
import uvicorn
import httpx

API_KEY = os.getenv('API_KEY')


app = FastAPI()

client = httpx.AsyncClient(base_url="https://base_url")


async def _reverse_proxy(request: Request):
    # add extra query params
    query_params = f"{request.url.query}&apikey={API_KEY}".encode("utf-8")
    # edit headers here
    headers = request.headers.mutablecopy()
    url = httpx.URL(
        path=request.url.path.replace("/proxy", ""),
        query=query_params,
    )
    rp_req = client.build_request(
        request.method,
        url,
        headers=headers.raw,
        content=request.stream()
    )
    rp_resp = await client.send(rp_req, stream=True)
    return StreamingResponse(
        rp_resp.aiter_raw(),
        status_code=rp_resp.status_code,
        headers=rp_resp.headers,
        background=BackgroundTask(rp_resp.aclose),
    )


app.add_route(
    "/proxy/{path:path}",
    _reverse_proxy,
    ["GET", "POST"]
)


if __name__ == "__main__":
    uvicorn.run(app, host="127.0.0.1", port=8080)