undici
![npm version](https://badge.fury.io/js/undici.svg)
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.
Install
npm i undici
Benchmarks
Machine: AMD EPYC 7502P
Node 14
http - keepalive x 7,179 ops/sec ±2.32% (272 runs sampled)
undici - pipeline x 16,843 ops/sec ±0.98% (279 runs sampled)
undici - request x 18,738 ops/sec ±0.67% (276 runs sampled)
undici - stream x 21,215 ops/sec ±0.66% (278 runs sampled)
undici - dispatch x 23,540 ops/sec ±0.62% (278 runs sampled)
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.
API
new undici.Client(url, opts)
A basic HTTP/1.1 client, mapped on top a single TCP/TLS connection. Pipelining is disabled
by default.
url
can be a string or a URL
object.
It should only include the protocol, hostname, and the port.
Options:
-
socketTimeout: Number
, the timeout after which a socket with active requests
will time out. Monitors time between activity on a connected socket.
Use 0
to disable it entirely. Default: 30e3
milliseconds (30s).
-
socketPath: String|Null
, an IPC endpoint, either Unix domain socket or Windows named pipe.
Default: null
.
-
idleTimeout: Number
, the timeout after which a socket without active requests
will time out. Monitors time between activity on a connected socket.
This value may be overriden by keep-alive hints from the server.
Default: 4e3
milliseconds (4s).
-
keepAlive: Boolean
, enable or disable keep alive connections.
Default: true
.
-
keepAliveMaxTimeout: Number
, the maximum allowed idleTimeout
when overriden by
keep-alive hints from the server.
Default: 600e3
milliseconds (10min).
-
keepAliveTimeoutThreshold: Number
, a number subtracted from server keep-alive hints
when overriding idleTimeout
to account for timing inaccuries caused by e.g.
transport latency.
Default: 1e3
milliseconds (1s).
-
pipelining: Number
, the amount of concurrent requests to be sent over the
single TCP/TLS connection according to RFC7230.
Carefully consider your workload and environment before enabling concurrent requests
as pipelining may reduce performance if used incorrectly. Pipelining is sensitive
to network stack settings as well as head of line blocking caused by e.g. long running requests.
Default: 1
.
-
tls: Object|Null
, an options object which in the case of https
will be passed to
tls.connect
.
Default: null
.
-
maxHeaderSize: Number
, the maximum length of request headers in bytes.
Default: 16384
(16KiB).
-
headersTimeout: Number
, the amount of time the parser will wait to receive the complete
HTTP headers (Node 14 and above only).
Default: 30e3
milliseconds (30s).
client.request(opts[, callback(err, data)]): Promise|Void
Performs a HTTP request.
Options:
path: String
method: String
opaque: Any
body: String|Buffer|Uint8Array|stream.Readable|Null
Default: null
.headers: Object|Array|Null
, an object with header-value pairs or an array with header-value pairs bi-indexed (['header1', 'value1', 'header2', 'value2']
).
Default: null
.signal: AbortController|EventEmitter|Null
Default: null
.requestTimeout: Number
, the timeout after which a request will time out, in
milliseconds. Monitors time between request being enqueued and receiving
a response. Use 0
to disable it entirely.
Default: 30e3
milliseconds (30s).idempotent: Boolean
, whether the requests can be safely retried or not.
If false
the request won't be sent until all preceeding
requests in the pipeline has completed.
Default: true
if method
is HEAD
or GET
.
Headers are represented by an object like this:
{
'content-length': '123',
'content-type': 'text/plain',
connection: 'keep-alive',
host: 'mysite.com',
accept: '*/*'
}
Or an array like this:
[
'content-length', '123',
'content-type', 'text/plain',
'connection', 'keep-alive',
'host', 'mysite.com',
'accept', '*/*'
]
Keys are lowercased. Values are not modified.
If you don't specify a host
header, it will be derived from the url
of the client instance.
The data
parameter in callback
is defined as follow:
statusCode: Number
opaque: Any
headers: Object
, an object where all keys have been lowercased.body: stream.Readable
response payload. A user must
either fully consume or destroy the body unless there is an error, or no further requests
will be processed.
Returns a promise if no callback is provided.
Example:
const { Client } = require('undici')
const client = new Client(`http://localhost:3000`)
client.request({
path: '/',
method: 'GET'
}, function (err, data) {
if (err) {
return
}
const {
statusCode,
headers,
body
} = data
console.log('response received', statusCode)
console.log('headers', headers)
body.setEncoding('utf8')
body.on('data', console.log)
client.close()
})
Non-idempotent requests will not be pipelined in order
to avoid indirect failures.
Idempotent requests will be automatically retried if
they fail due to indirect failure from the request
at the head of the pipeline. This does not apply to
idempotent requests with a stream request body.
Aborting a request
A request can may be aborted using either an AbortController
or an EventEmitter
.
To use AbortController
, you will need to npm i abort-controller
.
const { AbortController } = require('abort-controller')
const { Client } = require('undici')
const client = new Client('http://localhost:3000')
const abortController = new AbortController()
client.request({
path: '/',
method: 'GET',
signal: abortController.signal
}, function (err, data) {
console.log(err)
client.close()
})
abortController.abort()
Alternatively, any EventEmitter
that emits an 'abort'
event may be used as an abort controller:
const EventEmitter = require('events')
const { Client } = require('undici')
const client = new Client('http://localhost:3000')
const ee = new EventEmitter()
client.request({
path: '/',
method: 'GET',
signal: ee
}, function (err, data) {
console.log(err)
client.close()
})
ee.emit('abort')
Destroying the request or response body will have the same effect.
client.stream(opts, factory(data)[, callback(err)]): Promise|Void
A faster version of request
.
Unlike request
this method expects factory
to return a Writable
which the response will be
written to. This improves performance by avoiding
creating an intermediate Readable
when the user
expects to directly pipe the response body to a
Writable
.
Options:
The data
parameter in factory
is defined as follow:
statusCode: Number
headers: Object
, an object where all keys have been lowercased.opaque: Any
The data
parameter in callback
is defined as follow:
opaque: Any
trailers: Object
, an object where all keys have been lowercased.
Returns a promise if no callback is provided.
const { Client } = require('undici')
const client = new Client(`http://localhost:3000`)
const fs = require('fs')
client.stream({
path: '/',
method: 'GET',
opaque: filename
}, ({ statusCode, headers, opaque: filename }) => {
console.log('response received', statusCode)
console.log('headers', headers)
return fs.createWriteStream(filename)
}, (err) => {
if (err) {
console.error('failure', err)
} else {
console.log('success')
}
})
opaque
makes it possible to avoid creating a closure
for the factory
method:
function (req, res) {
return client.stream({ ...opts, opaque: res }, proxy)
}
Instead of:
function (req, res) {
return client.stream(opts, (data) => {
proxy({ ...data, opaque: res })
}
}
client.pipeline(opts, handler(data)): Duplex
For easy use with stream.pipeline
.
Options:
The data
parameter in handler
is defined as follow:
statusCode: Number
headers: Object
, an object where all keys have been lowercased.opaque: Any
body: stream.Readable
response payload. A user must
either fully consume or destroy the body unless there is an error, or no further requests
will be processed.
handler
should return a Readable
from which the result will be
read. Usually it should just return the body
argument unless
some kind of transformation needs to be performed based on e.g.
headers
or statusCode
.
The handler
should validate the response and save any
required state. If there is an error it should be thrown.
Returns a Duplex
which writes to the request and reads from
the response.
const { Client } = require('undici')
const client = new Client(`http://localhost:3000`)
const fs = require('fs')
const stream = require('stream')
stream.pipeline(
fs.createReadStream('source.raw'),
client.pipeline({
path: '/',
method: 'PUT',
}, ({ statusCode, headers, body }) => {
if (statusCode !== 201) {
throw new Error('invalid response')
}
if (isZipped(headers)) {
return pipeline(body, unzip(), () => {})
}
return body
}),
fs.createWriteStream('response.raw'),
(err) => {
if (err) {
console.error('failed')
} else {
console.log('succeeded')
}
}
)
client.upgrade(opts[, callback(err, data)]): Promise|Void
Upgrade to a different protocol.
Options:
path: String
opaque: Any
method: String
Default: GET
headers: Object|Null
, an object with header-value pairs.
Default: null
signal: AbortController|EventEmitter|Null
.
Default: null
requestTimeout: Number
, the timeout after which a request will time out, in
milliseconds. Monitors time between request being enqueued and receiving
a response. Use 0
to disable it entirely.
Default: 30e3
milliseconds (30s).protocol: String
, a string of comma separated protocols, in descending preference order.
Default: Websocket
.
The data
parameter in callback
is defined as follow:
headers: Object
, an object where all keys have been lowercased.socket: Duplex
opaque
Returns a promise if no callback is provided.
client.connect(opts[, callback(err, data)]): Promise|Void
Starts two-way communications with the requested resource.
Options:
path: String
opaque: Any
headers: Object|Null
, an object with header-value pairs.
Default: null
signal: AbortController|EventEmitter|Null
.
Default: null
requestTimeout: Number
, the timeout after which a request will time out, in
milliseconds. Monitors time between request being enqueued and receiving
a response. Use 0
to disable it entirely.
Default: 30e3
milliseconds (30s).
The data
parameter in callback
is defined as follow:
statusCode: Number
headers: Object
, an object where all keys have been lowercased.socket: Duplex
opaque: Any
Returns a promise if no callback is provided.
client.dispatch(opts, handler): Promise|Void
This is the low level API which all the preceeding APIs are implemented on top of.
This API is expected to evolve through semver-major versions and is less stable
than the preceeding higher level APIs. It is primarily intended for library developers
who implement higher level APIs on top of this.
Options:
path: String
method: String
body: String|Buffer|Uint8Array|stream.Readable|Null
Default: null
.headers: Object|Null
, an object with header-value pairs.
Default: null
.requestTimeout: Number
, the timeout after which a request will time out, in
milliseconds. Monitors time between request being enqueued and receiving
a response. Use 0
to disable it entirely.
Default: 30e3
milliseconds (30s).idempotent: Boolean
, whether the requests can be safely retried or not.
If false
the request won't be sent until all preceeding
requests in the pipeline has completed.
Default: true
if method
is HEAD
or GET
.
The handler
parameter is defined as follow:
onConnect(abort)
, invoked before request is dispatched on socket.
May be invoked multiple times when a request is retried when the request at the head of the pipeline fails.
abort(): Void
, abort request.
onUpgrade(statusCode, headers, socket): Void
, invoked when request is upgraded either due to a Upgrade
header or CONNECT
method.
statusCode: Number
headers: Array|Null
socket: Duplex
onHeaders(statusCode, headers, resume): Void
, invoked when statusCode and headers have been received.
May be invoked multiple times due to 1xx informational headers.
statusCode: Number
headers: Array|Null
, an array of key-value pairs. Keys are not automatically lowercased.resume(): Void
, resume onData
after returning false
.
onData(chunk): Boolean
, invoked when response payload data is received.
onComplete(trailers): Void
, invoked when response payload and trailers have been received and the request has completed.
onError(err): Void
, invoked when an error has occured.
The caller is responsible for handling the body
argument, in terms of 'error'
events and destroy()
:ing up until
the onConnect
handler has been invoked.
client.close([callback]): Promise|Void
Closes the client and gracefully waits fo enqueued requests to
complete before invoking the callback.
Returns a promise if no callback is provided.
client.destroy([err][, callback]): Promise|Void
Destroy the client abruptly with the given err
. All the pending and running
requests will be asynchronously aborted and error. Waits until socket is closed
before invoking the callback. Since this operation is asynchronously dispatched
there might still be some progress on dispatched requests.
Returns a promise if no callback is provided.
client.pipelining: Number
Property to get and set the pipelining factor.
client.pending: Number
Number of queued requests.
client.running: Number
Number of inflight requests.
client.size: Number
Number of pending and running requests.
client.connected: Boolean
True if the client has an active connection. The client will lazily
create a connection when it receives a request and will destroy it
if there is no activity for the duration of the timeout
value.
client.busy: Boolean
True if pipeline is saturated or blocked. Indicicates whether dispatching
further requests is meaningful.
client.closed: Boolean
True after client.close()
has been called.
client.destroyed: Boolean
True after client.destroyed()
has been called or client.close()
has been
called and the client shutdown has completed.
Events
-
'drain'
, emitted when pipeline is no longer fully
saturated.
-
'connect'
, emitted when a socket has been created and
connected. The client will connect once client.size > 0
.
-
'disconnect'
, emitted when socket has disconnected. The
first argument of the event is the error which caused the
socket to disconnect. The client will reconnect if or once
client.size > 0
.
new undici.Pool(url, opts)
A pool of Client
connected to the same upstream target.
Options:
- ... same as
Client
. connections
, the number of clients to create.
Default 10
.
Pool
does not guarantee that requests are dispatched in
order of invocation.
pool.request(opts[, callback]): Promise|Void
Calls client.request(opts, callback)
on one of the clients.
pool.stream(opts, factory[, callback]): Promise|Void
Calls client.stream(opts, factory, callback)
on one of the clients.
pool.pipeline(opts, handler): Duplex
Calls client.pipeline(opts, handler)
on one of the clients.
pool.upgrade(opts[, callback]): Promise|Void
Calls client.upgrade(opts, callback)
on one of the clients.
pool.connect(opts[, callback]): Promise|Void
Calls client.connect(opts, callback)
on one of the clients.
pool.dispatch(opts, handler): Void
Calls client.dispatch(opts, handler)
on one of the clients.
pool.close([callback]): Promise|Void
Calls client.close(callback)
on all the clients.
pool.destroy([err][, callback]): Promise|Void
Calls client.destroy(err, callback)
on all the clients.
undici.errors
Undici exposes a variety of error objects that you can use to enhance your error handling.
You can find all the error objects inside the errors
key.
const { errors } = require('undici')
Error | Error Codes | Description |
---|
InvalidArgumentError | UND_ERR_INVALID_ARG | passed an invalid argument. |
InvalidReturnValueError | UND_ERR_INVALID_RETURN_VALUE | returned an invalid value. |
SocketTimeoutError | UND_ERR_SOCKET_TIMEOUT | a socket exceeds the socketTimeout option. |
RequestTimeoutError | UND_ERR_REQUEST_TIMEOUT | a request exceeds the requestTimeout option. |
RequestAbortedError | UND_ERR_ABORTED | the request has been aborted by the user |
ClientDestroyedError | UND_ERR_DESTROYED | trying to use a destroyed client. |
ClientClosedError | UND_ERR_CLOSED | trying to use a closed client. |
SocketError | UND_ERR_SOCKET | there is an error with the socket. |
NotSupportedError | UND_ERR_NOT_SUPPORTED | encountered unsupported functionality. |
ContentLengthMismatchError | UND_ERR_CONTENT_LENGTH_MISMATCH | body does not match content-length header |
InformationalError | UND_ERR_INFO | expected error with reason |
TrailerMismatchError | UND_ERR_TRAILER_MISMATCH | trailers did not match specification |
Specification Compliance
This section documents parts of the HTTP/1.1 specification which Undici does
not support or does not fully implement.
Expect
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
Pipelining
Uncidi will only use pipelining if configured with a pipelining
factor
greater than 1
.
Undici always assumes that connections are persistent and will immediatly
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
Collaborators
License
MIT