main.py

#!/usr/bin/python3


from starlette.applications import Starlette
from starlette.responses import Response
from starlette.routing import Route

import httpx


async def topic(request):
    host = request.headers.get("host")
    path = request.path_params["path"]
    target_url = f"https://{host}/{path}"

    pubKey = request.headers.get("crypto-key").encode()
    salt = request.headers.get("encryption").encode()

    body = b"aesgcm\nEncryption: " + salt + b"\nCrypto-Key: " + pubKey + b"\n" + await request.body()

    headers = dict(request.headers)
    del headers["content-encoding"]
    del headers["content-length"]

    # Forward the request to the target URL
    async with httpx.AsyncClient() as client:
        upstream_response = await client.request(
            method=request.method,
            url=target_url,
            headers=headers,
            data=body,
            params=request.query_params,
        )

    return Response(
        content=upstream_response.content, status_code=upstream_response.status_code
    )


app = Starlette(
    debug=True,
    routes=[
        Route("/{path:path}", topic, methods=["POST"]),
    ],
)

nginx_nfty.conf

map $http_content_encoding    $ntfy_backend {
  "aesgcm"    "127.0.0.1:8000";
  default     "127.0.0.1:2586";
}

server {
  listen 80;
  listen [::]:80;
  server_name YOURDOMAIN;

  location /generic {
    proxy_pass http://127.0.0.1:5000;
  }

  location / {
    add_header alt-svc 'h3-27=":443"; ma=86400, h3-28=":443"; ma=86400, h3-29=":443"; ma=86400, h3=":443"; ma=86400';

    proxy_pass http://$ntfy_backend;
    proxy_http_version 1.1;

    proxy_set_header Host $host;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

    proxy_connect_timeout 3m;
    proxy_send_timeout 3m;
    proxy_read_timeout 3m;

    client_max_body_size 0; # Stream request body to backend
  }
}