POST requests hang forever

[silent hemlock]

I'm trying to deploy my app using caddy as a reverse proxy. My Tanstack Start app (behind fastify) works fine using docker but as soon as I add caddy:

services:
  proxy:
    image: caddy:2-alpine
    restart: unless-stopped
    ports:
      - "8080:80"
    volumes:
      - ./Caddyfile:/etc/caddy/Caddyfile

  app:
    restart: unless-stopped
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
      - PORT=3000

where Caddyfile is:

:80 {
    encode gzip zstd

    reverse_proxy app:3000 {
        header_up Host {host}
        header_up X-Real-IP {remote_host}
        header_up X-Forwarded-For {remote_host}
        header_up X-Forwarded-Proto {scheme}
    }
}

then GET requests work fine (even files) but POST requests hang forever.

Does anyone have any idea what could cause this?

The POST request reaches fastify for sure (since I see a incoming request log in Fastify). It's a POST request made by Tanstack Query (using the native integration with Tanstack Start) to a server function. If I add a console.info to the start of the function it never gets executed.

Without the proxy the app works just fine (including post requests and even file uploads)

This is the Fastify server file. Probably not the source of the issue but might as well...

[drowsy vigil]

can you provide a full reproducer project that is easily runnable?

[silent hemlock]

@drowsy vigil Yup, here it is: https://github.com/shoooe/tanstack-start-fastify/pull/2

[drowsy vigil]

can you please create a github issue for this in the router repo?

otherwise its hard to track all the open topics

[silent hemlock]

Yup. I wasn't sure it was a bug

[drowsy vigil]

i dont know either

but if in doubt, just create an issue with a reproducer

we will eventually figure it out

[silent hemlock]

Here it is: https://github.com/TanStack/router/issues/5275
Closing this topic then

[silent hemlock]

Seems like Caddy is not the issue. Seems like toNodeHandler is the culprit. It's reproducible even in a regular pnpm build && pnpm start now

[drowsy vigil]

can you reproduce outside of start?

with just toNodeHandler and a dummy handler?

[silent hemlock]

What's the dummiest handler?

  fetch(request: Request) {
    return new Response();
  }
```?

[drowsy vigil]

thats very dummy!

might want to try a async version as well if that does not fail

[silent hemlock]

It's not reproducible neither with that nor with the async version of that

Seems like toNodeHandler + import handler from "@tanstack/react-start/server-entry" is the problem

POST requests hang forever

It's reproducible even without input data (although Tanstack Start seems to send something anyway)

[drowsy vigil]

It's reproducible
with or without start?

[silent hemlock]

with start

it's only reproducible when you mix toNodeHandler and @tanstack/react-start/server-entry