first commit

libraries/fetch-utils/.gitignore

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+
+# managed by monorepo$ bin/update_build_scripts
+.npmrc

libraries/fetch-utils/.mocharc.json

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+{
+  "ui": "bdd",
+  "recursive": "true",
+  "reporter": "spec",
+  "require": "test/setup.js"
+}

libraries/fetch-utils/.nvmrc

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+20.18.2

libraries/fetch-utils/buildscript.txt

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+fetch-utils
+--dependencies=None
+--docker-repos=gcr.io/overleaf-ops
+--env-add=
+--env-pass-through=
+--esmock-loader=False
+--is-library=True
+--node-version=20.18.2
+--public-repo=False
+--script-version=4.7.0

libraries/fetch-utils/index.js

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+const _ = require('lodash')
+const { Readable } = require('node:stream')
+const OError = require('@overleaf/o-error')
+const fetch = require('node-fetch')
+const http = require('node:http')
+const https = require('node:https')
+
+/**
+ * @import { Response } from 'node-fetch'
+ */
+
+/**
+ * Make a request and return the parsed JSON response.
+ *
+ * @param {string | URL} url - request URL
+ * @param {any} [opts] - fetch options
+ * @return {Promise<any>} the parsed JSON response
+ * @throws {RequestFailedError} if the response has a failure status code
+ */
+async function fetchJson(url, opts = {}) {
+  const { json } = await fetchJsonWithResponse(url, opts)
+  return json
+}
+
+async function fetchJsonWithResponse(url, opts = {}) {
+  const { fetchOpts } = parseOpts(opts)
+  fetchOpts.headers = fetchOpts.headers ?? {}
+  fetchOpts.headers.Accept = fetchOpts.headers.Accept ?? 'application/json'
+
+  const response = await performRequest(url, fetchOpts)
+  if (!response.ok) {
+    const body = await maybeGetResponseBody(response)
+    throw new RequestFailedError(url, opts, response, body)
+  }
+
+  const json = await response.json()
+  return { json, response }
+}
+
+/**
+ * Make a request and return a stream.
+ *
+ * If the response body is destroyed, the request is aborted.
+ *
+ * @param {string | URL} url - request URL
+ * @param {any} [opts] - fetch options
+ * @return {Promise<Readable>}
+ * @throws {RequestFailedError} if the response has a failure status code
+ */
+async function fetchStream(url, opts = {}) {
+  const { stream } = await fetchStreamWithResponse(url, opts)
+  return stream
+}
+
+async function fetchStreamWithResponse(url, opts = {}) {
+  const { fetchOpts, abortController } = parseOpts(opts)
+  const response = await performRequest(url, fetchOpts)
+
+  if (!response.ok) {
+    const body = await maybeGetResponseBody(response)
+    throw new RequestFailedError(url, opts, response, body)
+  }
+
+  abortOnDestroyedResponse(abortController, response)
+
+  const stream = response.body
+  return { stream, response }
+}
+
+/**
+ * Make a request and discard the response.
+ *
+ * @param {string | URL} url - request URL
+ * @param {any} [opts] - fetch options
+ * @return {Promise<Response>}
+ * @throws {RequestFailedError} if the response has a failure status code
+ */
+async function fetchNothing(url, opts = {}) {
+  const { fetchOpts } = parseOpts(opts)
+  const response = await performRequest(url, fetchOpts)
+  if (!response.ok) {
+    const body = await maybeGetResponseBody(response)
+    throw new RequestFailedError(url, opts, response, body)
+  }
+  await discardResponseBody(response)
+  return response
+}
+
+/**
+ * Make a request and extract the redirect from the response.
+ *
+ * @param {string | URL} url - request URL
+ * @param {any} [opts] - fetch options
+ * @return {Promise<string>}
+ * @throws {RequestFailedError} if the response has a non redirect status code or missing Location header
+ */
+async function fetchRedirect(url, opts = {}) {
+  const { location } = await fetchRedirectWithResponse(url, opts)
+  return location
+}
+
+/**
+ * Make a request and extract the redirect from the response.
+ *
+ * @param {string | URL} url - request URL
+ * @param {object} opts - fetch options
+ * @return {Promise<{location: string, response: Response}>}
+ * @throws {RequestFailedError} if the response has a non redirect status code or missing Location header
+ */
+async function fetchRedirectWithResponse(url, opts = {}) {
+  const { fetchOpts } = parseOpts(opts)
+  fetchOpts.redirect = 'manual'
+  const response = await performRequest(url, fetchOpts)
+  if (response.status < 300 || response.status >= 400) {
+    const body = await maybeGetResponseBody(response)
+    throw new RequestFailedError(url, opts, response, body)
+  }
+  const location = response.headers.get('Location')
+  if (!location) {
+    const body = await maybeGetResponseBody(response)
+    throw new RequestFailedError(url, opts, response, body).withCause(
+      new OError('missing Location response header on 3xx response', {
+        headers: Object.fromEntries(response.headers.entries()),
+      })
+    )
+  }
+  await discardResponseBody(response)
+  return { location, response }
+}
+
+/**
+ * Make a request and return a string.
+ *
+ * @param {string | URL} url - request URL
+ * @param {any} [opts] - fetch options
+ * @return {Promise<string>}
+ * @throws {RequestFailedError} if the response has a failure status code
+ */
+async function fetchString(url, opts = {}) {
+  const { body } = await fetchStringWithResponse(url, opts)
+  return body
+}
+
+async function fetchStringWithResponse(url, opts = {}) {
+  const { fetchOpts } = parseOpts(opts)
+  const response = await performRequest(url, fetchOpts)
+  if (!response.ok) {
+    const body = await maybeGetResponseBody(response)
+    throw new RequestFailedError(url, opts, response, body)
+  }
+  const body = await response.text()
+  return { body, response }
+}
+
+class RequestFailedError extends OError {
+  constructor(url, opts, response, body) {
+    super('request failed', {
+      url,
+      method: opts.method ?? 'GET',
+      status: response.status,
+    })
+
+    this.response = response
+    if (body != null) {
+      this.body = body
+    }
+  }
+}
+
+function parseOpts(opts) {
+  const fetchOpts = _.omit(opts, ['json', 'signal', 'basicAuth'])
+  if (opts.json) {
+    setupJsonBody(fetchOpts, opts.json)
+  }
+  if (opts.basicAuth) {
+    setupBasicAuth(fetchOpts, opts.basicAuth)
+  }
+
+  const abortController = new AbortController()
+  fetchOpts.signal = abortController.signal
+  if (opts.signal) {
+    abortOnSignal(abortController, opts.signal)
+  }
+  if (opts.body instanceof Readable) {
+    abortOnDestroyedRequest(abortController, fetchOpts.body)
+  }
+  return { fetchOpts, abortController }
+}
+
+function setupJsonBody(fetchOpts, json) {
+  fetchOpts.body = JSON.stringify(json)
+  fetchOpts.headers = fetchOpts.headers ?? {}
+  fetchOpts.headers['Content-Type'] = 'application/json'
+}
+
+function setupBasicAuth(fetchOpts, basicAuth) {
+  fetchOpts.headers = fetchOpts.headers ?? {}
+  fetchOpts.headers.Authorization =
+    'Basic ' +
+    Buffer.from(`${basicAuth.user}:${basicAuth.password}`).toString('base64')
+}
+
+function abortOnSignal(abortController, signal) {
+  const listener = () => {
+    abortController.abort(signal.reason)
+  }
+  if (signal.aborted) {
+    abortController.abort(signal.reason)
+  }
+  signal.addEventListener('abort', listener)
+}
+
+function abortOnDestroyedRequest(abortController, stream) {
+  stream.on('close', () => {
+    if (!stream.readableEnded) {
+      abortController.abort()
+    }
+  })
+}
+
+function abortOnDestroyedResponse(abortController, response) {
+  response.body.on('close', () => {
+    if (!response.bodyUsed) {
+      abortController.abort()
+    }
+  })
+}
+
+async function performRequest(url, fetchOpts) {
+  let response
+  try {
+    response = await fetch(url, fetchOpts)
+  } catch (err) {
+    if (fetchOpts.body instanceof Readable) {
+      fetchOpts.body.destroy()
+    }
+    throw OError.tag(err, err.message, {
+      url,
+      method: fetchOpts.method ?? 'GET',
+    })
+  }
+  if (fetchOpts.body instanceof Readable) {
+    response.body.on('close', () => {
+      if (!fetchOpts.body.readableEnded) {
+        fetchOpts.body.destroy()
+      }
+    })
+  }
+  return response
+}
+
+async function discardResponseBody(response) {
+  // eslint-disable-next-line no-unused-vars
+  for await (const chunk of response.body) {
+    // discard the body
+  }
+}
+
+/**
+ * @param {Response} response
+ */
+async function maybeGetResponseBody(response) {
+  try {
+    return await response.text()
+  } catch (err) {
+    return null
+  }
+}
+
+// Define custom http and https agents with support for connect timeouts
+
+class ConnectTimeoutError extends OError {
+  constructor(options) {
+    super('connect timeout', options)
+  }
+}
+
+function withTimeout(createConnection, options, callback) {
+  if (options.connectTimeout) {
+    // Wrap createConnection in a timeout
+    const timer = setTimeout(() => {
+      socket.destroy(new ConnectTimeoutError(options))
+    }, options.connectTimeout)
+    const socket = createConnection(options, (err, stream) => {
+      clearTimeout(timer)
+      callback(err, stream)
+    })
+    return socket
+  } else {
+    // Fallback to default createConnection
+    return createConnection(options, callback)
+  }
+}
+
+class CustomHttpAgent extends http.Agent {
+  createConnection(options, callback) {
+    return withTimeout(super.createConnection.bind(this), options, callback)
+  }
+}
+class CustomHttpsAgent extends https.Agent {
+  createConnection(options, callback) {
+    return withTimeout(super.createConnection.bind(this), options, callback)
+  }
+}
+
+module.exports = {
+  fetchJson,
+  fetchJsonWithResponse,
+  fetchStream,
+  fetchStreamWithResponse,
+  fetchNothing,
+  fetchRedirect,
+  fetchRedirectWithResponse,
+  fetchString,
+  fetchStringWithResponse,
+  RequestFailedError,
+  ConnectTimeoutError,
+  CustomHttpAgent,
+  CustomHttpsAgent,
+}

libraries/fetch-utils/package.json

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+{
+  "name": "@overleaf/fetch-utils",
+  "version": "0.1.0",
+  "description": "utilities for node-fetch",
+  "main": "index.js",
+  "scripts": {
+    "test": "npm run lint && npm run format && npm run types:check && npm run test:unit",
+    "lint": "eslint --ext .js --ext .cjs --ext .ts --max-warnings 0 --format unix .",
+    "lint:fix": "eslint --fix --ext .js --ext .cjs --ext .ts .",
+    "format": "prettier --list-different $PWD/'**/*.{js,cjs,ts}'",
+    "format:fix": "prettier --write $PWD/'**/*.{js,cjs,ts}'",
+    "test:ci": "npm run test:unit",
+    "test:unit": "mocha --exit test/**/*.{js,cjs}",
+    "types:check": "tsc --noEmit"
+  },
+  "author": "Overleaf (https://www.overleaf.com)",
+  "license": "AGPL-3.0-only",
+  "devDependencies": {
+    "@types/node-fetch": "^2.6.11",
+    "body-parser": "^1.20.3",
+    "chai": "^4.3.6",
+    "chai-as-promised": "^7.1.1",
+    "express": "^4.21.2",
+    "mocha": "^11.1.0",
+    "typescript": "^5.0.4"
+  },
+  "dependencies": {
+    "@overleaf/o-error": "*",
+    "lodash": "^4.17.21",
+    "node-fetch": "^2.7.0",
+    "selfsigned": "^2.4.1"
+  }
+}

libraries/fetch-utils/test/setup.js

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+const chai = require('chai')
+const chaiAsPromised = require('chai-as-promised')
+
+chai.use(chaiAsPromised)

libraries/fetch-utils/test/unit/FetchUtilsTests.js

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+const { expect } = require('chai')
+const { FetchError, AbortError } = require('node-fetch')
+const { Readable } = require('node:stream')
+const { once } = require('node:events')
+const { TestServer } = require('./helpers/TestServer')
+const selfsigned = require('selfsigned')
+const {
+  fetchJson,
+  fetchStream,
+  fetchNothing,
+  fetchRedirect,
+  fetchString,
+  RequestFailedError,
+  CustomHttpAgent,
+  CustomHttpsAgent,
+} = require('../..')
+
+const HTTP_PORT = 30001
+const HTTPS_PORT = 30002
+
+const attrs = [{ name: 'commonName', value: 'example.com' }]
+const pems = selfsigned.generate(attrs, { days: 365 })
+
+const PRIVATE_KEY = pems.private
+const PUBLIC_CERT = pems.cert
+
+const dns = require('node:dns')
+const _originalLookup = dns.lookup
+// Custom DNS resolver function
+dns.lookup = (hostname, options, callback) => {
+  if (hostname === 'example.com') {
+    // If the hostname is our test case, return the ip address for the test server
+    if (options?.all) {
+      callback(null, [{ address: '127.0.0.1', family: 4 }])
+    } else {
+      callback(null, '127.0.0.1', 4)
+    }
+  } else {
+    // Otherwise, use the default lookup
+    _originalLookup(hostname, options, callback)
+  }
+}
+
+describe('fetch-utils', function () {
+  before(async function () {
+    this.server = new TestServer()
+    await this.server.start(HTTP_PORT, HTTPS_PORT, {
+      key: PRIVATE_KEY,
+      cert: PUBLIC_CERT,
+    })
+    this.url = path => `http://example.com:${HTTP_PORT}${path}`
+    this.httpsUrl = path => `https://example.com:${HTTPS_PORT}${path}`
+  })
+
+  beforeEach(function () {
+    this.server.lastReq = undefined
+  })
+
+  after(async function () {
+    await this.server.stop()
+  })
+
+  describe('fetchJson', function () {
+    it('parses a JSON response', async function () {
+      const json = await fetchJson(this.url('/json/hello'))
+      expect(json).to.deep.equal({ msg: 'hello' })
+    })
+
+    it('parses JSON in the request', async function () {
+      const json = await fetchJson(this.url('/json/add'), {
+        method: 'POST',
+        json: { a: 2, b: 3 },
+      })
+      expect(json).to.deep.equal({ sum: 5 })
+    })
+
+    it('accepts stringified JSON as body', async function () {
+      const json = await fetchJson(this.url('/json/add'), {
+        method: 'POST',
+        body: JSON.stringify({ a: 2, b: 3 }),
+        headers: { 'Content-Type': 'application/json' },
+      })
+      expect(json).to.deep.equal({ sum: 5 })
+    })
+
+    it('throws a FetchError when the payload is not JSON', async function () {
+      await expect(fetchJson(this.url('/hello'))).to.be.rejectedWith(FetchError)
+    })
+
+    it('aborts the request if JSON parsing fails', async function () {
+      await expect(fetchJson(this.url('/large'))).to.be.rejectedWith(FetchError)
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('handles errors when the payload is JSON', async function () {
+      await expect(fetchJson(this.url('/json/500'))).to.be.rejectedWith(
+        RequestFailedError
+      )
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('handles errors when the payload is not JSON', async function () {
+      await expect(fetchJson(this.url('/500'))).to.be.rejectedWith(
+        RequestFailedError
+      )
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('supports abort signals', async function () {
+      await expect(
+        abortOnceReceived(
+          signal => fetchJson(this.url('/hang'), { signal }),
+          this.server
+        )
+      ).to.be.rejectedWith(AbortError)
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('supports basic auth', async function () {
+      const json = await fetchJson(this.url('/json/basic-auth'), {
+        basicAuth: { user: 'user', password: 'pass' },
+      })
+      expect(json).to.deep.equal({ key: 'verysecret' })
+    })
+
+    it("destroys the request body if it doesn't get consumed", async function () {
+      const stream = Readable.from(infiniteIterator())
+      await fetchJson(this.url('/json/ignore-request'), {
+        method: 'POST',
+        body: stream,
+      })
+      expect(stream.destroyed).to.be.true
+    })
+  })
+
+  describe('fetchStream', function () {
+    it('returns a stream', async function () {
+      const stream = await fetchStream(this.url('/large'))
+      const text = await streamToString(stream)
+      expect(text).to.equal(this.server.largePayload)
+    })
+
+    it('aborts the request when the stream is destroyed', async function () {
+      const stream = await fetchStream(this.url('/large'))
+      stream.destroy()
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('aborts the request when the request body is destroyed before transfer', async function () {
+      const stream = Readable.from(infiniteIterator())
+      const promise = fetchStream(this.url('/hang'), {
+        method: 'POST',
+        body: stream,
+      })
+      stream.destroy()
+      await expect(promise).to.be.rejectedWith(AbortError)
+      await wait(80)
+      expect(this.server.lastReq).to.be.undefined
+    })
+
+    it('aborts the request when the request body is destroyed during transfer', async function () {
+      const stream = Readable.from(infiniteIterator())
+      // Note: this test won't work on `/hang`
+      const promise = fetchStream(this.url('/sink'), {
+        method: 'POST',
+        body: stream,
+      })
+      await once(this.server.events, 'request-received')
+      stream.destroy()
+      await expect(promise).to.be.rejectedWith(AbortError)
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('handles errors', async function () {
+      await expect(fetchStream(this.url('/500'))).to.be.rejectedWith(
+        RequestFailedError
+      )
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('supports abort signals', async function () {
+      await expect(
+        abortOnceReceived(
+          signal => fetchStream(this.url('/hang'), { signal }),
+          this.server
+        )
+      ).to.be.rejectedWith(AbortError)
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('destroys the request body when an error occurs', async function () {
+      const stream = Readable.from(infiniteIterator())
+      await expect(
+        abortOnceReceived(
+          signal =>
+            fetchStream(this.url('/hang'), {
+              method: 'POST',
+              body: stream,
+              signal,
+            }),
+          this.server
+        )
+      ).to.be.rejectedWith(AbortError)
+      expect(stream.destroyed).to.be.true
+    })
+  })
+
+  describe('fetchNothing', function () {
+    it('closes the connection', async function () {
+      await fetchNothing(this.url('/large'))
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('aborts the request when the request body is destroyed before transfer', async function () {
+      const stream = Readable.from(infiniteIterator())
+      const promise = fetchNothing(this.url('/hang'), {
+        method: 'POST',
+        body: stream,
+      })
+      stream.destroy()
+      await expect(promise).to.be.rejectedWith(AbortError)
+      expect(this.server.lastReq).to.be.undefined
+    })
+
+    it('aborts the request when the request body is destroyed during transfer', async function () {
+      const stream = Readable.from(infiniteIterator())
+      // Note: this test won't work on `/hang`
+      const promise = fetchNothing(this.url('/sink'), {
+        method: 'POST',
+        body: stream,
+      })
+      await once(this.server.events, 'request-received')
+      stream.destroy()
+      await expect(promise).to.be.rejectedWith(AbortError)
+      await wait(80)
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it("doesn't abort the request if the request body ends normally", async function () {
+      const stream = Readable.from('hello there')
+      await fetchNothing(this.url('/sink'), { method: 'POST', body: stream })
+    })
+
+    it('handles errors', async function () {
+      await expect(fetchNothing(this.url('/500'))).to.be.rejectedWith(
+        RequestFailedError
+      )
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('supports abort signals', async function () {
+      await expect(
+        abortOnceReceived(
+          signal => fetchNothing(this.url('/hang'), { signal }),
+          this.server
+        )
+      ).to.be.rejectedWith(AbortError)
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('destroys the request body when an error occurs', async function () {
+      const stream = Readable.from(infiniteIterator())
+      await expect(
+        abortOnceReceived(
+          signal =>
+            fetchNothing(this.url('/hang'), {
+              method: 'POST',
+              body: stream,
+              signal,
+            }),
+          this.server
+        )
+      ).to.be.rejectedWith(AbortError)
+      expect(stream.destroyed).to.be.true
+    })
+  })
+
+  describe('fetchString', function () {
+    it('returns a string', async function () {
+      const body = await fetchString(this.url('/hello'))
+      expect(body).to.equal('hello')
+    })
+
+    it('handles errors', async function () {
+      await expect(fetchString(this.url('/500'))).to.be.rejectedWith(
+        RequestFailedError
+      )
+      await expectRequestAborted(this.server.lastReq)
+    })
+  })
+
+  describe('fetchRedirect', function () {
+    it('returns the immediate redirect', async function () {
+      const body = await fetchRedirect(this.url('/redirect/1'))
+      expect(body).to.equal(this.url('/redirect/2'))
+    })
+
+    it('rejects status 200', async function () {
+      await expect(fetchRedirect(this.url('/hello'))).to.be.rejectedWith(
+        RequestFailedError
+      )
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('rejects empty redirect', async function () {
+      await expect(fetchRedirect(this.url('/redirect/empty-location')))
+        .to.be.rejectedWith(RequestFailedError)
+        .and.eventually.have.property('cause')
+        .and.to.have.property('message')
+        .to.equal('missing Location response header on 3xx response')
+      await expectRequestAborted(this.server.lastReq)
+    })
+
+    it('handles errors', async function () {
+      await expect(fetchRedirect(this.url('/500'))).to.be.rejectedWith(
+        RequestFailedError
+      )
+      await expectRequestAborted(this.server.lastReq)
+    })
+  })
+
+  describe('CustomHttpAgent', function () {
+    it('makes an http request successfully', async function () {
+      const agent = new CustomHttpAgent({ connectTimeout: 100 })
+      const body = await fetchString(this.url('/hello'), { agent })
+      expect(body).to.equal('hello')
+    })
+
+    it('times out when accessing a non-routable address', async function () {
+      const agent = new CustomHttpAgent({ connectTimeout: 10 })
+      await expect(fetchString('http://10.255.255.255/', { agent }))
+        .to.be.rejectedWith(FetchError)
+        .and.eventually.have.property('message')
+        .and.to.equal(
+          'request to http://10.255.255.255/ failed, reason: connect timeout'
+        )
+    })
+  })
+
+  describe('CustomHttpsAgent', function () {
+    it('makes an https request successfully', async function () {
+      const agent = new CustomHttpsAgent({
+        connectTimeout: 100,
+        ca: PUBLIC_CERT,
+      })
+      const body = await fetchString(this.httpsUrl('/hello'), { agent })
+      expect(body).to.equal('hello')
+    })
+
+    it('rejects an untrusted server', async function () {
+      const agent = new CustomHttpsAgent({
+        connectTimeout: 100,
+      })
+      await expect(fetchString(this.httpsUrl('/hello'), { agent }))
+        .to.be.rejectedWith(FetchError)
+        .and.eventually.have.property('code')
+        .and.to.equal('DEPTH_ZERO_SELF_SIGNED_CERT')
+    })
+
+    it('times out when accessing a non-routable address', async function () {
+      const agent = new CustomHttpsAgent({ connectTimeout: 10 })
+      await expect(fetchString('https://10.255.255.255/', { agent }))
+        .to.be.rejectedWith(FetchError)
+        .and.eventually.have.property('message')
+        .and.to.equal(
+          'request to https://10.255.255.255/ failed, reason: connect timeout'
+        )
+    })
+  })
+})
+
+async function streamToString(stream) {
+  let s = ''
+  for await (const chunk of stream) {
+    s += chunk
+  }
+  return s
+}
+
+async function* infiniteIterator() {
+  let i = 1
+  while (true) {
+    yield `chunk ${i++}\n`
+  }
+}
+
+/**
+ * @param {(signal: AbortSignal) => Promise<any>} func
+ * @param {TestServer} server
+ */
+async function abortOnceReceived(func, server) {
+  const controller = new AbortController()
+  const promise = func(controller.signal)
+  await once(server.events, 'request-received')
+  controller.abort()
+  return await promise
+}
+
+async function expectRequestAborted(req) {
+  if (!req.destroyed) {
+    try {
+      await once(req, 'close')
+    } catch (err) {
+      // `once` throws if req emits an 'error' event.
+      // We ignore `Error: aborted` when the request is aborted.
+      if (err.message !== 'aborted') {
+        throw err
+      }
+    }
+  }
+  expect(req.destroyed).to.be.true
+}
+
+const wait = ms => new Promise(resolve => setTimeout(resolve, ms))

libraries/fetch-utils/test/unit/helpers/TestServer.js

@@ -0,0 +1,130 @@
+const express = require('express')
+const bodyParser = require('body-parser')
+const { EventEmitter } = require('node:events')
+const http = require('node:http')
+const https = require('node:https')
+const { promisify } = require('node:util')
+
+class TestServer {
+  constructor() {
+    this.app = express()
+    this.events = new EventEmitter()
+
+    this.app.use(bodyParser.json())
+    this.app.use((req, res, next) => {
+      this.events.emit('request-received')
+      this.lastReq = req
+      next()
+    })
+
+    // Plain text endpoints
+
+    this.app.get('/hello', (req, res) => {
+      res.send('hello')
+    })
+
+    this.largePayload = 'x'.repeat(16 * 1024 * 1024)
+    this.app.get('/large', (req, res) => {
+      res.send(this.largePayload)
+    })
+
+    this.app.get('/204', (req, res) => {
+      res.status(204).end()
+    })
+
+    this.app.get('/empty', (req, res) => {
+      res.end()
+    })
+
+    this.app.get('/500', (req, res) => {
+      res.sendStatus(500)
+    })
+
+    this.app.post('/sink', (req, res) => {
+      req.on('data', () => {})
+      req.on('end', () => {
+        res.status(204).end()
+      })
+    })
+
+    // JSON endpoints
+
+    this.app.get('/json/hello', (req, res) => {
+      res.json({ msg: 'hello' })
+    })
+
+    this.app.post('/json/add', (req, res) => {
+      const { a, b } = req.body
+      res.json({ sum: a + b })
+    })
+
+    this.app.get('/json/500', (req, res) => {
+      res.status(500).json({ error: 'Internal server error' })
+    })
+
+    this.app.get('/json/basic-auth', (req, res) => {
+      const expectedAuth =
+        'Basic ' + Buffer.from('user:pass').toString('base64')
+      if (req.headers.authorization === expectedAuth) {
+        res.json({ key: 'verysecret' })
+      } else {
+        res.status(401).json({ error: 'unauthorized' })
+      }
+    })
+
+    this.app.post('/json/ignore-request', (req, res) => {
+      res.json({ msg: 'hello' })
+    })
+
+    // Never returns
+
+    this.app.get('/hang', (req, res) => {})
+    this.app.post('/hang', (req, res) => {})
+
+    // Redirect
+
+    this.app.get('/redirect/1', (req, res) => {
+      res.redirect('/redirect/2')
+    })
+    this.app.get('/redirect/2', (req, res) => {
+      res.send('body after redirect')
+    })
+    this.app.get('/redirect/empty-location', (req, res) => {
+      res.sendStatus(302)
+    })
+  }
+
+  start(port, httpsPort, httpsOptions) {
+    const startHttp = new Promise((resolve, reject) => {
+      this.server = http.createServer(this.app).listen(port, err => {
+        if (err) {
+          reject(err)
+        } else {
+          resolve()
+        }
+      })
+    })
+    const startHttps = new Promise((resolve, reject) => {
+      this.https_server = https
+        .createServer(httpsOptions, this.app)
+        .listen(httpsPort, err => {
+          if (err) {
+            reject(err)
+          } else {
+            resolve()
+          }
+        })
+    })
+    return Promise.all([startHttp, startHttps])
+  }
+
+  stop() {
+    const stopHttp = promisify(this.server.close).bind(this.server)
+    const stopHttps = promisify(this.https_server.close).bind(this.https_server)
+    this.server.closeAllConnections()
+    this.https_server.closeAllConnections()
+    return Promise.all([stopHttp(), stopHttps()])
+  }
+}
+
+module.exports = { TestServer }

libraries/fetch-utils/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "extends": "../../tsconfig.backend.json",
+  "include": [
+    "**/*.js",
+    "**/*.cjs"
+  ]
+}