feat: Support autoSelectFamily when connecting.

README.md

@@ -405,6 +405,18 @@ implementations in Deno and Cloudflare Workers.
 
 Refs: https://fetch.spec.whatwg.org/#atomic-http-redirect-handling
 
+## Workarounds
+
+### Network address family autoselection.
+
+If you experience problem when connecting to a remote server that is resolved by your DNS servers to a IPv6 (AAAA record)
+first, there are chances that your local router or ISP might have problem connecting to IPv6 networks. In that case
+undici will throw an error with code `UND_ERR_CONNECT_TIMEOUT`. 
+
+If the target server resolves to both a IPv6 and IPv4 (A records) address and you are using a compatible Node version 
+(18.3.0 and above), you can fix the problem by providing the `autoSelectFamily` option (support by both `undici.request`
+and `undici.Agent`) which will enable the family autoselection algorithm when establishing the connection.
+
 ## Collaborators
 
 * [__Daniele Belardi__](https://github.com/dnlup), <https://www.npmjs.com/~dnlup>

docs/api/Client.md

@@ -28,6 +28,8 @@ Returns: `Client`
 * **connect** `ConnectOptions | Function | null` (optional) - Default: `null`.
 * **strictContentLength** `Boolean` (optional) - Default: `true` - Whether to treat request content length mismatches as errors. If true, an error is thrown when the request content-length header doesn't match the length of the request body.
 * **interceptors** `{ Client: DispatchInterceptor[] }` - Default: `[RedirectInterceptor]` - A list of interceptors that are applied to the dispatch method. Additional logic can be applied (such as, but not limited to: 302 status code handling, authentication, cookies, compression and caching). Note that the behavior of interceptors is Experimental and might change at any given time.
+* **autoSelectFamily**: `boolean` (optional) - Default: depends on local Node version, on Node 18.13.0 and above is `false`. Enables a family autodetection algorithm that loosely implements section 5 of [RFC 8305](https://tools.ietf.org/html/rfc8305#section-5). See [here](https://nodejs.org/api/net.html#socketconnectoptions-connectlistener) for more details. This option is ignored if not supported by the current Node version.
+* **autoSelectFamilyAttemptTimeout**: `number` - Default: depends on local Node version, on Node 18.13.0 and above is `250`. The amount of time in milliseconds to wait for a connection attempt to finish before trying the next address when using the `autoSelectFamily` option. See [here](https://nodejs.org/api/net.html#socketconnectoptions-connectlistener) for more details.
 
 #### Parameter: `ConnectOptions`
 

index.js

@@ -20,10 +20,6 @@ const DecoratorHandler = require('./lib/handler/DecoratorHandler')
 const RedirectHandler = require('./lib/handler/RedirectHandler')
 const createRedirectInterceptor = require('./lib/interceptor/redirectInterceptor')
 
-const nodeVersion = process.versions.node.split('.')
-const nodeMajor = Number(nodeVersion[0])
-const nodeMinor = Number(nodeVersion[1])
-
 let hasCrypto
 try {
   require('crypto')
@@ -100,7 +96,7 @@ function makeDispatcher (fn) {
 module.exports.setGlobalDispatcher = setGlobalDispatcher
 module.exports.getGlobalDispatcher = getGlobalDispatcher
 
-if (nodeMajor > 16 || (nodeMajor === 16 && nodeMinor >= 8)) {
+if (util.nodeMajor > 16 || (util.nodeMajor === 16 && util.nodeMinor >= 8)) {
   let fetchImpl = null
   module.exports.fetch = async function fetch (resource) {
     if (!fetchImpl) {
@@ -127,7 +123,7 @@ if (nodeMajor > 16 || (nodeMajor === 16 && nodeMinor >= 8)) {
   module.exports.getGlobalOrigin = getGlobalOrigin
 }
 
-if (nodeMajor >= 16) {
+if (util.nodeMajor >= 16) {
   const { deleteCookie, getCookies, getSetCookies, setCookie } = require('./lib/cookies')
 
   module.exports.deleteCookie = deleteCookie
@@ -141,7 +137,7 @@ if (nodeMajor >= 16) {
   module.exports.serializeAMimeType = serializeAMimeType
 }
 
-if (nodeMajor >= 18 && hasCrypto) {
+if (util.nodeMajor >= 18 && hasCrypto) {
   const { WebSocket } = require('./lib/websocket/websocket')
 
   module.exports.WebSocket = WebSocket

lib/client.js

@@ -109,7 +109,9 @@ class Client extends DispatcherBase {
     connect,
     maxRequestsPerClient,
     localAddress,
-    maxResponseSize
+    maxResponseSize,
+    autoSelectFamily,
+    autoSelectFamilyAttemptTimeout
   } = {}) {
     super()
 
@@ -185,12 +187,20 @@ class Client extends DispatcherBase {
       throw new InvalidArgumentError('maxResponseSize must be a positive number')
     }
 
+    if (
+      autoSelectFamilyAttemptTimeout != null &&
+      (!Number.isInteger(autoSelectFamilyAttemptTimeout) || autoSelectFamilyAttemptTimeout < -1)
+    ) {
+      throw new InvalidArgumentError('autoSelectFamilyAttemptTimeout must be a positive number')
+    }
+
     if (typeof connect !== 'function') {
       connect = buildConnector({
         ...tls,
         maxCachedSessions,
         socketPath,
         timeout: connectTimeout,
+        ...(util.nodeHasAutoSelectFamily && autoSelectFamily ? { autoSelectFamily, autoSelectFamilyAttemptTimeout } : undefined),
         ...connect
       })
     }

lib/core/request.js

@@ -34,10 +34,6 @@ const channels = {}
 
 let extractBody
 
-const nodeVersion = process.versions.node.split('.')
-const nodeMajor = Number(nodeVersion[0])
-const nodeMinor = Number(nodeVersion[1])
-
 try {
   const diagnosticsChannel = require('diagnostics_channel')
   channels.create = diagnosticsChannel.channel('undici:request:create')
@@ -172,7 +168,7 @@ class Request {
     }
 
     if (util.isFormDataLike(this.body)) {
-      if (nodeMajor < 16 || (nodeMajor === 16 && nodeMinor < 8)) {
+      if (util.nodeMajor < 16 || (util.nodeMajor === 16 && util.nodeMinor < 8)) {
         throw new InvalidArgumentError('Form-Data bodies are only supported in node v16.8 and newer.')
       }
 

lib/core/util.js

@@ -10,6 +10,8 @@ const { Blob } = require('buffer')
 const nodeUtil = require('util')
 const { stringify } = require('querystring')
 
+const [nodeMajor, nodeMinor] = process.versions.node.split('.').map(v => Number(v))
+
 function nop () {}
 
 function isStream (obj) {
@@ -420,5 +422,8 @@ module.exports = {
   validateHandler,
   getSocketInfo,
   isFormDataLike,
-  buildURL
+  buildURL,
+  nodeMajor,
+  nodeMinor,
+  nodeHasAutoSelectFamily: nodeMajor > 18 || (nodeMajor === 18 && nodeMinor >= 13)
 }

lib/fetch/index.js

@@ -53,7 +53,7 @@ const {
 const { kHeadersList } = require('../core/symbols')
 const EE = require('events')
 const { Readable, pipeline } = require('stream')
-const { isErrored, isReadable } = require('../core/util')
+const { isErrored, isReadable, nodeMajor, nodeMinor } = require('../core/util')
 const { dataURLProcessor, serializeAMimeType } = require('./dataURL')
 const { TransformStream } = require('stream/web')
 const { getGlobalDispatcher } = require('../global')
@@ -64,10 +64,6 @@ const { STATUS_CODES } = require('http')
 let resolveObjectURL
 let ReadableStream = globalThis.ReadableStream
 
-const nodeVersion = process.versions.node.split('.')
-const nodeMajor = Number(nodeVersion[0])
-const nodeMinor = Number(nodeVersion[1])
-
 class Fetch extends EE {
   constructor (dispatcher) {
     super()

lib/pool.js

@@ -32,6 +32,8 @@ class Pool extends PoolBase {
     tls,
     maxCachedSessions,
     socketPath,
+    autoSelectFamily,
+    autoSelectFamilyAttemptTimeout,
     ...options
   } = {}) {
     super()
@@ -54,6 +56,7 @@ class Pool extends PoolBase {
         maxCachedSessions,
         socketPath,
         timeout: connectTimeout == null ? 10e3 : connectTimeout,
+        ...(util.nodeHasAutoSelectFamily && autoSelectFamily ? { autoSelectFamily, autoSelectFamilyAttemptTimeout } : undefined),
         ...connect
       })
     }

package.json

@@ -78,6 +78,7 @@
     "concurrently": "^7.1.0",
     "cronometro": "^1.0.5",
     "delay": "^5.0.0",
+    "dns-packet": "^5.4.0",
     "docsify-cli": "^4.4.3",
     "form-data": "^4.0.0",
     "formdata-node": "^4.3.1",
@@ -91,7 +92,6 @@
     "pre-commit": "^1.2.2",
     "proxy": "^1.0.2",
     "proxyquire": "^2.1.3",
-    "semver": "^7.3.5",
     "sinon": "^15.0.0",
     "snazzy": "^9.0.0",
     "standard": "^17.0.0",

test/autoselectfamily.js

@@ -0,0 +1,187 @@
+'use strict'
+
+const { test } = require('tap')
+const dgram = require('dgram')
+const { Resolver } = require('dns')
+const dnsPacket = require('dns-packet')
+const { createServer } = require('http')
+const { Client, Agent, request } = require('..')
+const { nodeHasAutoSelectFamily } = require('../lib/core/util')
+
+function _lookup (resolver, hostname, options, cb) {
+  resolver.resolve(hostname, 'ANY', (err, replies) => {
+    if (err) {
+      return cb(err)
+    }
+
+    const hosts = replies
+      .map((r) => ({ address: r.address, family: r.type === 'AAAA' ? 6 : 4 }))
+      .sort((a, b) => b.family - a.family)
+
+    if (options.all === true) {
+      return cb(null, hosts)
+    }
+
+    return cb(null, hosts[0].address, hosts[0].family)
+  })
+}
+
+function createDnsServer (ipv6Addr, ipv4Addr, cb) {
+  // Create a DNS server which replies with a AAAA and a A record for the same host
+  const socket = dgram.createSocket('udp4')
+
+  socket.on('message', (msg, { address, port }) => {
+    const parsed = dnsPacket.decode(msg)
+
+    const response = dnsPacket.encode({
+      type: 'answer',
+      id: parsed.id,
+      questions: parsed.questions,
+      answers: [
+        { type: 'AAAA', class: 'IN', name: 'example.org', data: '::1', ttl: 123 },
+        { type: 'A', class: 'IN', name: 'example.org', data: '127.0.0.1', ttl: 123 }
+      ]
+    })
+
+    socket.send(response, port, address)
+  })
+
+  socket.bind(0, () => {
+    const resolver = new Resolver()
+    resolver.setServers([`127.0.0.1:${socket.address().port}`])
+
+    cb(null, { dnsServer: socket, lookup: _lookup.bind(null, resolver) })
+  })
+}
+
+if (nodeHasAutoSelectFamily) {
+  test('with autoSelectFamily enable the request succeeds when using request', (t) => {
+    t.plan(3)
+
+    createDnsServer('::1', '127.0.0.1', function (_, { dnsServer, lookup }) {
+      const server = createServer((req, res) => {
+        res.end('hello')
+      })
+
+      t.teardown(() => {
+        server.close()
+        dnsServer.close()
+      })
+
+      server.listen(0, '127.0.0.1', () => {
+        const agent = new Agent({ connect: { lookup }, autoSelectFamily: true })
+
+        request(
+          `http://example.org:${server.address().port}/`, {
+            method: 'GET',
+            dispatcher: agent
+          }, (err, { statusCode, body }) => {
+            t.error(err)
+
+            let response = Buffer.alloc(0)
+
+            body.on('data', chunk => {
+              response = Buffer.concat([response, chunk])
+            })
+
+            body.on('end', () => {
+              t.strictSame(statusCode, 200)
+              t.strictSame(response.toString('utf-8'), 'hello')
+            })
+          })
+      })
+    })
+  })
+
+  test('with autoSelectFamily enable the request succeeds when using a client', (t) => {
+    t.plan(3)
+
+    createDnsServer('::1', '127.0.0.1', function (_, { dnsServer, lookup }) {
+      const server = createServer((req, res) => {
+        res.end('hello')
+      })
+
+      t.teardown(() => {
+        server.close()
+        dnsServer.close()
+      })
+
+      server.listen(0, '127.0.0.1', () => {
+        const client = new Client(`http://example.org:${server.address().port}`, { connect: { lookup }, autoSelectFamily: true })
+
+        t.teardown(client.destroy.bind(client))
+
+        client.request({
+          path: '/',
+          method: 'GET'
+        }, (err, { statusCode, body }) => {
+          t.error(err)
+
+          let response = Buffer.alloc(0)
+
+          body.on('data', chunk => {
+            response = Buffer.concat([response, chunk])
+          })
+
+          body.on('end', () => {
+            t.strictSame(statusCode, 200)
+            t.strictSame(response.toString('utf-8'), 'hello')
+          })
+        })
+      })
+    })
+  })
+}
+
+test('with autoSelectFamily disabled the request fails when using request', (t) => {
+  t.plan(1)
+
+  createDnsServer('::1', '127.0.0.1', function (_, { dnsServer, lookup }) {
+    const server = createServer((req, res) => {
+      res.end('hello')
+    })
+
+    t.teardown(() => {
+      server.close()
+      dnsServer.close()
+    })
+
+    server.listen(0, '127.0.0.1', () => {
+      const agent = new Agent({ connect: { lookup } })
+
+      request(`http://example.org:${server.address().port}`, {
+        method: 'GET',
+        dispatcher: agent
+      }, (err, { statusCode, body }) => {
+        t.strictSame(err.code, 'ECONNREFUSED')
+      })
+    })
+  })
+})
+
+test('with autoSelectFamily disabled the request fails when using a client', (t) => {
+  t.plan(1)
+
+  createDnsServer('::1', '127.0.0.1', function (_, { dnsServer, lookup }) {
+    const server = createServer((req, res) => {
+      res.end('hello')
+    })
+
+    t.teardown(() => {
+      server.close()
+      dnsServer.close()
+    })
+
+    server.listen(0, '127.0.0.1', () => {
+      const client = new Client(`http://example.org:${server.address().port}`, { connect: { lookup } })
+      t.teardown(client.destroy.bind(client))
+
+      client.request({
+        path: '/',
+        method: 'GET'
+      }, (err, { statusCode, body }) => {
+        t.strictSame(err.code, 'ECONNREFUSED')
+      })
+    })
+  })
+})

test/balanced-pool.js

@@ -2,9 +2,9 @@
 
 const { test } = require('tap')
 const { BalancedPool, Pool, Client, errors } = require('..')
+const { nodeMajor } = require('../lib/core/util')
 const { createServer } = require('http')
 const { promisify } = require('util')
-const semver = require('semver')
 
 test('throws when factory is not a function', (t) => {
   t.plan(2)
@@ -437,7 +437,7 @@ const cases = [
     expectedRatios: [0.34, 0.34, 0.32],
 
     // Skip because the behavior of Node.js has changed
-    skip: semver.satisfies(process.version, '>= 19.0.0')
+    skip: nodeMajor >= 19
   },
 
   // 8