Basic proxy service using FastAPI (asynchronous)

proxy.py

import logging
from http import HTTPStatus

import httpx
import uvicorn.logging
from fastapi import FastAPI, HTTPException, Request, Response
from fastapi.routing import APIRoute

TARGET_URL = "http://127.0.0.1:8080"  # Change this to the URL you want to proxy requests to


async def proxy(request: Request) -> Response:
    """Proxy handler function to forward incoming requests to a target URL.

    Args:
        request: The incoming request object.

    Returns:
        Response: The response object with the forwarded content and headers.
    """
    try:
        async with httpx.AsyncClient() as client:
            body = await request.body()
            # noinspection PyTypeChecker
            response = await client.request(
                method=request.method,
                url=TARGET_URL + request.url.path,
                headers=dict(request.headers),
                cookies=request.cookies,
                params=dict(request.query_params),
                data=body.decode(),
            )

            # If the response content-type is text/html, we need to rewrite links in it
            content_type = response.headers.get("content-type", "")
            if "text/html" in content_type:
                content = response.text
                # Modify content if necessary (e.g., rewriting links)
                # content = modify_html_links(content)
            else:
                content = response.content
            response.headers.pop("content-encoding", None)

            return Response(content, response.status_code, response.headers, content_type)
    except httpx.RequestError as exc:
        logging.getLogger("uvicorn.error").error(exc)
        raise HTTPException(status_code=HTTPStatus.BAD_GATEWAY.value, detail=HTTPStatus.BAD_GATEWAY.phrase)


if __name__ == '__main__':
    uvicorn.run(
        app=FastAPI(
            routes=[
                APIRoute("/{_:path}", methods=["GET", "POST", "PUT", "DELETE", "PATCH", "OPTIONS"], endpoint=proxy)
            ]
        )
    )