Change default "user-agent" from undici #2306
Description
What is the problem this feature will solve?
Currently, Node.js uses undici for its fetch implementation. This sets undici as the default user agent.
From Node.js' perspective, undici is an implementation detail and so it should have its own user agent header.
For context at Next.js, we stopped polyfilling globalThis.fetch in favor of the platform-provided alternative (previously using node-fetch), and started getting reports where users did not know where the requests with the undici user agent were coming from.
I've tested the current behavior in different runtimes, here is Node.js, Bun and Deno for comparison:
- Node.js
node node.mjsprints: undici:
// node.mjs
import { createServer } from 'http'
const server = createServer((req, res) => {
console.log(req.headers['user-agent'])
res.end()
}).listen(3000)
await fetch('http://localhost:3000')
server.close()
process.exit(0)- Bun
bun bun.jsprints: Bun/1.0.2:
// bun.js
const server = Bun.serve({
port: 3000,
fetch: (req) => console.log(req.headers.get('user-agent')),
})
await fetch('http://localhost:3000')
server.stop()- Deno
deno run --allow-net deno.jsprints: Deno/1.37.1:
// deno.js
Deno.serve({ port: 3000 }, (request) => {
console.log(request.headers.get('user-agent'))
return new Response()
})
await fetch('http://localhost:3000')
Deno.exit(0)What is the feature you are proposing to solve the problem?
I propose that the default user agent in Node.js changes to the format used by Deno, and Bun for consistency.
Example: Node/18.18.0
What alternatives have you considered?
Related: nodejs/node#43852 nodejs/node#43851