`http.ServerResponse` only flushes content automatically to network after second write call #5869

arthurfiorette · 2023-09-21T19:28:21Z

What version of Bun is running?

1.0.2+37edd5a6e389265738e89265bcbdf2999cb81a49

What platform is your computer?

Linux 5.15.90.1-microsoft-standard-WSL2 x86_64 x86_64

What steps can reproduce the bug?

When creating a http server and piping a stream into the response, it does not flushes the content in the first write, only after the second.

import http from 'http'
import { PassThrough } from 'stream'

http
  .createServer((req, res) => {
    res.setHeader('Content-Type', 'text/html; charset=utf-8')

    const stream = new PassThrough()
    stream.pipe(res)

    if (req.url === '/single') {
      stream.write('hello')
    }

    if (req.url === '/double') {
      stream.write('hello')
      stream.write(' world')
    }

    // Does not ends the stream because ending
    // would forcefully flush contents.
  })
  .listen(8080, () => {
    console.log('http://localhost:8080')
  })

What is the expected behavior?

Calling localhost:8080/single would output hello and calling localhost:8080/double would still print hello world.

This behaviour is right in nodejs:

# prints hello in nodejs
curl http://localhost:8080/single -vN
*   Trying 127.0.0.1:8080...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /single HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.68.0
> Accept: */*
>
hello

# prints hello world in nodejs
curl http://localhost:8080/double -vN
*   Trying 127.0.0.1:8080...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /double HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.68.0
> Accept: */*
> 
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Content-Type: text/html; charset=utf-8
< Date: Thu, 21 Sep 2023 19:23:46 GMT
< Transfer-Encoding: chunked
< 
hello world

What do you see instead?

Calling localhost:8080/single would never give any output:

# Does not prints hello
curl http://localhost:8080/single -vN
*   Trying 127.0.0.1:8080...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /single HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.68.0
> Accept: */*
>

Calling localhost:8080/double would give both generated output:

# Prints hello world
curl http://localhost:8080/double -vN
*   Trying 127.0.0.1:8080...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /double HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.68.0
> Accept: */*
> 
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Content-Type: text/html; charset=utf-8
< Date: Thu, 21 Sep 2023 19:23:46 GMT
< Transfer-Encoding: chunked
< 
hello world

Additional information

No response

The text was updated successfully, but these errors were encountered:

EmNudge · 2024-04-20T18:06:40Z

Ran into the same issue. Here is a slightly different example to see this in the browser.

node index.mjs will work fine, whereas bun run index.mjs will wait a full 2 seconds before rendering any part of the page.

import { createServer } from "node:http";

createServer((_req, res) => {
  res.writeHead(200, {
    "Content-Type": "text/html",
    "Transfer-Encoding": "chunked",
  });

  res.write(`
    <html>
      <head>
        <title>Hello Page!</title>
      </head>
      <body>
        <h1>Hello</h1>
  `);

  // Uncomment this line to fix bun
  // res.write('')

  setTimeout(() => {
    res.write(`
        <h2>World</h2>
        <style>h1 { background: aqua }</style>
      </body>
    </html>
    `);
    res.end();
  }, 2000);
}).listen(8080);

arthurfiorette added the bug Something isn't working label Sep 21, 2023

arthurfiorette changed the title ~~http.ServerResponse only flushes after second write~~ http.ServerResponse only flushes content automatically to network after second write call Sep 21, 2023

Electroid added the node.js Compatibility with Node.js APIs label Sep 21, 2023

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`http.ServerResponse` only flushes content automatically to network after second write call #5869

`http.ServerResponse` only flushes content automatically to network after second write call #5869

arthurfiorette commented Sep 21, 2023

EmNudge commented Apr 20, 2024

http.ServerResponse only flushes content automatically to network after second write call #5869

http.ServerResponse only flushes content automatically to network after second write call #5869

Comments

arthurfiorette commented Sep 21, 2023

What version of Bun is running?

What platform is your computer?

What steps can reproduce the bug?

What is the expected behavior?

What do you see instead?

Additional information

EmNudge commented Apr 20, 2024

`http.ServerResponse` only flushes content automatically to network after second write call #5869

`http.ServerResponse` only flushes content automatically to network after second write call #5869