How to remove 'text/plain;charset=UTF-8' from content-type header? about ofetch HOT 7 CLOSED

I can confirm that this is only an issue with undici fetch (globalThis.fetch)

from ofetch.

Actually, it is only an issue with undici fetch in ohmyfetch context, here's a snippet to test it out :

import http from "node:http";

import { $fetch } from "ohmyfetch/node";

const server = http.createServer((req, res) => {
   console.log(req.headers);

  res.end();
});

server.listen(8000);

for(const fetchImpl of [fetch, $fetch]) {
	await fetchImpl("http://localhost:8000", {
		body: { lo: "dibidon" },

		headers: {
			"content-type": "application/json"
		},

		method: "POST"
	});
}

globalThis.fetch:

{
  host: 'localhost:8000',
  connection: 'keep-alive',
  'content-type': 'application/json',
  accept: '*/*',
  'accept-language': '*',
  'sec-fetch-mode': 'cors',
  'user-agent': 'undici',
  'accept-encoding': 'gzip, deflate',
  'content-length': '0'
}

ohmyfetch:

{
  host: 'localhost:8000',
  connection: 'keep-alive',
  'content-type': 'application/json, text/plain;charset=UTF-8',
  accept: 'application/json',
  'accept-language': '*',
  'sec-fetch-mode': 'cors',
  'user-agent': 'undici',
  'accept-encoding': 'gzip, deflate',
  'content-length': '16'
}

I tried on node 16 and I had no issue with node-fetch.
So, it's an issue with ohmyfetch's implementation of undici fetching. It doesn't happen with unjs/node-fetch-native alone.
I also realized it doesn't happen if you omit the body.

from ofetch.

Let me close this issue because ohfetch does no longer support undici as of v1.0.0 and there is a workaround for the issue like using other fetch implementation.

from ofetch.

@ian4uia You have made a typo, headers are case sensitive, you can overwrite content-type with lowercase instead of capitalised Content-Type

from ofetch.

You have made a typo, headers are case sensitive, you can overwrite content-type with lowercase instead of capitalised Content-Type

it's not a typo, it's supposed to work too, overwriting using content-type does not work better

return $fetch("https://whatever", { 
	body: {},

	headers: {
		"content-type": "application/json"
	},

	method: "POST"
});

Result:

Content-Type: application/json, text/plain;charset=UTF-8

I'm thinking that this is potentially an undici issue

from ofetch.

Could that it's always adding the text/plain;charset=UTF-8 on any content-type which would be not very helpful.

But what I saw in fetch.js #L121 if you wanted to overwrite it you needs to use content-type instead of Content-Type

from ofetch.

I'm pretty sure that works for ohmyfetch, but it's probably an issue with the underlying fetch libraries used (for my case, it's using undici.fetch)

from ofetch.