A HTTP/1.1 client, written from scratch for Node.js.

Undici means eleven in Italian. 1.1 -> 11 -> Eleven -> Undici. It is also a Stranger Things reference.

npm i undici

Machine: AMD EPYC 7502P

Node 15

http - keepalive x 12,028 ops/sec ±2.60% (265 runs sampled)
undici - pipeline x 31,321 ops/sec ±0.77% (276 runs sampled)
undici - request x 36,612 ops/sec ±0.71% (277 runs sampled)
undici - stream x 41,291 ops/sec ±0.90% (268 runs sampled)
undici - dispatch x 47,319 ops/sec ±1.17% (263 runs sampled)

The benchmark is a simple hello world example using a single unix socket with pipelining.

import { request } from 'undici'

const {
  statusCode,
  headers,
  trailers,
  body
} = await request('https://localhost:3000/foo')

console.log('response received', statusCode)
console.log('headers', headers)

for await (const data of body) {
  console.log('data', data)
}

console.log('trailers', trailers)

This section documents parts of the HTTP/1.1 specification which Undici does not support or does not fully implement.

Undici does not support the Expect request header field. The request body is always immediately sent and the 100 Continue response will be ignored.

Refs: https://tools.ietf.org/html/rfc7231#section-5.1.1

Uncidi will only use pipelining if configured with a pipelining factor greater than 1.

Undici always assumes that connections are persistent and will immediately pipeline requests, without checking whether the connection is persistent. Hence, automatic fallback to HTTP/1.0 or HTTP/1.1 without pipelining is not supported.

Undici will immediately pipeline when retrying requests afters a failed connection. However, Undici will not retry the first remaining requests in the prior pipeline and instead error the corresponding callback/promise/stream.

• Refs: https://tools.ietf.org/html/rfc2616#section-8.1.2.2
• Refs: https://tools.ietf.org/html/rfc7230#section-6.3.2

• Daniele Belardi, https://www.npmjs.com/~dnlup
• Matteo Collina, https://www.npmjs.com/~matteo.collina
• Robert Nagy, https://www.npmjs.com/~ronag

MIT