[http]: Missing Content-Length Header when Responding to HEAD Requests

[qwerzl]

Version

v23.5.0

Platform

Darwin MacbookPro-2.local 24.0.0 Darwin Kernel Version 24.0.0: Tue Sep 24 23:39:07 PDT 2024; root:xnu-11215.1.12~1/RELEASE_ARM64_T6000 arm64 arm Darwin

Subsystem

http

What steps will reproduce the bug?

Just start the server and curl the results:

import { createServer } from 'node:http';
const hostname = '127.0.0.1';
const port = 3000;
const server = createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello World');
});
server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});

curl -v http://127.0.0.1:3000/ to get the response header through GET;
curl -I http://127.0.0.1:3000/ to get the response header through HEAD.

How often does it reproduce? Is there a required condition?

Always. No required condition.

What is the expected behavior? Why is that the expected behavior?

According to MDN:

The HEAD HTTP method requests the metadata of a resource in the form of headers that the server would have sent if the GET method was used instead. This method can be used in cases where a URL might produce a large download, for example, a HEAD request can read the Content-Length header to check the file size before downloading the file with a GET.

HEAD requests are a bit different than other request methods without body because it is essentially GETs with body removed. It should be allowed to return all the headers that a GET request returns.

What do you see instead?

However, in the current http library, all responses without body will not return the Content-Length header:

node/lib/_http_outgoing.js

Line 550 in 7bc2946

if (!this._hasBody) {

Curl results:

• -I (HEAD Requests)

  ~> curl -I http://127.0.0.1:3000/
  HTTP/1.1 200 OK
  Content-Type: text/plain
  Date: [redacted]
  

• -v (GET Requests)

  ~> curl -v http://127.0.0.1:3000/
  *   Trying 127.0.0.1:3000...
  * Connected to 127.0.0.1 (127.0.0.1) port 3000
  > GET / HTTP/1.1
  > Host: 127.0.0.1:3000
  > User-Agent: curl/8.7.1
  > Accept: */*
  >
  * Request completely sent off
  < HTTP/1.1 200 OK
  < Content-Type: text/plain
  < Date: [redacted]
  < Content-Length: 11
  <
  * Connection #0 to host 127.0.0.1 left intact
  Hello World
  

Additional information

No response