Express post request with transfer-encoding chuncked has no body

[co-sic]

What version of Bun is running?

1.0.25, 1.1.8

What platform is your computer?

Linux 6.5.0-15-generic x86_64 x86_64

What steps can reproduce the bug?

I'm running express and apollo-server (latest versions) and i am having the problem that the body of an incomming post request is empty in certain situations. I narrowed it down to the "transfer-encoding": "chuncked" header beeing present and/or the 'content-lenght' header beeing not present. If tried the same failing request and send it through a proxy first (ngrok) and then it worked. You can see the diff of the requests here https://www.diffchecker.com/0AdUpa8R/ (Left side is failing, right side is working).

What is the expected behavior?

No response

What do you see instead?

No response

Additional information

No response

[Electroid]

Thanks for reporting, mind sharing some code to reproduce this issue?

[co-sic]

Hey @Electroid i added a example here to reproduce this: https://github.com/co-sic/bun-playground/tree/cosmo-bun-apollo-server

[ambergristle]

Hi! I've potentially run into a similar issue.

I use Docker to build a Next.js (14.0.3) app running on Bun (oven/bun:1.0-slim). I use App Router to GET some data from a third party (Marketstack), and return it to the client.

The third party service responds with chunk-encoded data. When deployed (on Railway, via Docker) large (e.g., ~400 rows) responses fail on json parse (SyntaxError: Unexpected end of JSON). Small (~30 rows) responses work ok both locally and in deployment. Locally (via Docker), the app mostly has no issue; I've been able to repro a couple times, but I'm not sure how. Deploying with Node instead of Bun seems to work regardless of response size.

I added a log of the response before json parse, and those (larger) responses that fail log a size of 0kb, while responses that are (ultimately) parsed ok have a non-zero size.

Source code from the jshttp lib seems to make its way into the error logs (if left uncaught).

I'm wondering whether this has anything to do with:

• https://github.com/oven-sh/bun/issues/4139
• https://github.com/oven-sh/bun/pull/4127

Here's a permalink to the failing point in my repo. I'm currently working on a more contained/easily-reproducible example.

[ambergristle]

Locally (via Docker), the app mostly has no issue; I've been able to repro a couple times, but I'm not sure how. Deploying with Node instead of Bun seems to work regardless of response size.

I just discovered that using bun --bun run dev locally is breaking. Works fine (locally) with bun dev and bun run dev.

  const response = await fetch(url)
    .then(async (res) => {
      if (res.ok) {
        return res.json()
      }
    })

// results in:

 ⨯ SyntaxError: Unexpected end of JSON input
    at json (native)
    at <anonymous> (:20:28)
    at <anonymous> (:18:55)
    at processTicksAndRejections (:61:39)
 ⨯ SyntaxError: Unexpected end of JSON input
    at json (native)
    at <anonymous> (:20:28)
    at <anonymous> (:18:55)
    at processTicksAndRejections (:61:39)
digest: "1774337577"

[co-sic]

Hey @Electroid any chance on getting a fix (or even workaround) for this soon? Sorry for the ping, but this is currently blocking and i need to consider to maybe move my bun production service back to node again if it will take a longer time to fix.

[co-sic]

I just check and the issue is still there with bun v1.1.8

[RobinVanCauter]

We've seen this issue as well while building an express backend using bun as the runtime for an existing client (so we can't change the way it's performing its requests).

So def. still an issue with Bun v1.1.12

When ran through node it works fine.

[vitalyavolyn]

Still an issue in bun 1.1.29 :( I have to use node for now

[vitalyavolyn]

Here's a tiny repro repo: https://github.com/vitalyavolyn/bun-chunked-repro

[Jarred-Sumner]

I believe this PR will fix it - #14384, but it's not going to be easy to merge