use private properties in Headers (#3269)

Author: KhafraDev

benchmarks/fetch/headers-length32.mjs

@@ -1,5 +1,5 @@
 import { bench, run } from 'mitata'
-import { Headers } from '../../lib/web/fetch/headers.js'
+import { Headers, getHeadersList } from '../../lib/web/fetch/headers.js'
 
 const headers = new Headers(
   [
@@ -38,11 +38,7 @@ const headers = new Headers(
   ].map((v) => [v, ''])
 )
 
-const kHeadersList = Reflect.ownKeys(headers).find(
-  (c) => String(c) === 'Symbol(headers list)'
-)
-
-const headersList = headers[kHeadersList]
+const headersList = getHeadersList(headers)
 
 const kHeadersSortedMap = Reflect.ownKeys(headersList).find(
   (c) => String(c) === 'Symbol(headers map sorted)'

benchmarks/fetch/headers.mjs

@@ -1,5 +1,5 @@
 import { bench, group, run } from 'mitata'
-import { Headers } from '../../lib/web/fetch/headers.js'
+import { Headers, getHeadersList } from '../../lib/web/fetch/headers.js'
 
 const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
 const charactersLength = characters.length
@@ -27,13 +27,9 @@ for (const [name, length] of Object.entries(settings)) {
 
   const headersSorted = new Headers(headers)
 
-  const kHeadersList = Reflect.ownKeys(headers).find(
-    (c) => String(c) === 'Symbol(headers list)'
-  )
-
-  const headersList = headers[kHeadersList]
+  const headersList = getHeadersList(headers)
 
-  const headersListSorted = headersSorted[kHeadersList]
+  const headersListSorted = getHeadersList(headersSorted)
 
   const kHeadersSortedMap = Reflect.ownKeys(headersList).find(
     (c) => String(c) === 'Symbol(headers map sorted)'

lib/core/symbols.js

@@ -8,7 +8,6 @@ module.exports = {
   kQueue: Symbol('queue'),
   kConnect: Symbol('connect'),
   kConnecting: Symbol('connecting'),
-  kHeadersList: Symbol('headers list'),
   kKeepAliveDefaultTimeout: Symbol('default keep alive timeout'),
   kKeepAliveMaxTimeout: Symbol('max keep alive timeout'),
   kKeepAliveTimeoutThreshold: Symbol('keep alive timeout threshold'),

lib/web/cookies/util.js

@@ -1,7 +1,7 @@
 'use strict'
 
 const assert = require('node:assert')
-const { kHeadersList } = require('../../core/symbols')
+const { getHeadersList: internalGetHeadersList } = require('../fetch/headers')
 
 /**
  * @param {string} value
@@ -278,8 +278,10 @@ function stringify (cookie) {
 let kHeadersListNode
 
 function getHeadersList (headers) {
-  if (headers[kHeadersList]) {
-    return headers[kHeadersList]
+  try {
+    return internalGetHeadersList(headers)
+  } catch {
+    // fall-through
   }
 
   if (!kHeadersListNode) {

lib/web/fetch/headers.js

@@ -2,8 +2,7 @@
 
 'use strict'
 
-const { kHeadersList, kConstruct } = require('../../core/symbols')
-const { kGuard } = require('./symbols')
+const { kConstruct } = require('../../core/symbols')
 const { kEnumerableProperty } = require('../../core/util')
 const {
   iteratorMixin,
@@ -103,19 +102,18 @@ function appendHeader (headers, name, value) {
   // 3. If headers’s guard is "immutable", then throw a TypeError.
   // 4. Otherwise, if headers’s guard is "request" and name is a
   //    forbidden header name, return.
+  // 5. Otherwise, if headers’s guard is "request-no-cors":
+  //    TODO
   // Note: undici does not implement forbidden header names
-  if (headers[kGuard] === 'immutable') {
+  if (getHeadersGuard(headers) === 'immutable') {
     throw new TypeError('immutable')
-  } else if (headers[kGuard] === 'request-no-cors') {
-    // 5. Otherwise, if headers’s guard is "request-no-cors":
-    // TODO
   }
 
   // 6. Otherwise, if headers’s guard is "response" and name is a
   //    forbidden response-header name, return.
 
   // 7. Append (name, value) to headers’s header list.
-  return headers[kHeadersList].append(name, value, false)
+  return getHeadersList(headers).append(name, value, false)
 
   // 8. If headers’s guard is "request-no-cors", then remove
   //    privileged no-CORS request headers from headers
@@ -357,16 +355,20 @@ class HeadersList {
 
 // https://fetch.spec.whatwg.org/#headers-class
 class Headers {
+  #guard
+  #headersList
+
   constructor (init = undefined) {
     if (init === kConstruct) {
       return
     }
-    this[kHeadersList] = new HeadersList()
+
+    this.#headersList = new HeadersList()
 
     // The new Headers(init) constructor steps are:
 
     // 1. Set this’s guard to "none".
-    this[kGuard] = 'none'
+    this.#guard = 'none'
 
     // 2. If init is given, then fill this with init.
     if (init !== undefined) {
@@ -416,22 +418,20 @@ class Headers {
     // 5. Otherwise, if this’s guard is "response" and name is
     //    a forbidden response-header name, return.
     // Note: undici does not implement forbidden header names
-    if (this[kGuard] === 'immutable') {
+    if (this.#guard === 'immutable') {
       throw new TypeError('immutable')
-    } else if (this[kGuard] === 'request-no-cors') {
-      // TODO
     }
 
     // 6. If this’s header list does not contain name, then
     //    return.
-    if (!this[kHeadersList].contains(name, false)) {
+    if (!this.#headersList.contains(name, false)) {
       return
     }
 
     // 7. Delete name from this’s header list.
     // 8. If this’s guard is "request-no-cors", then remove
     //    privileged no-CORS request headers from this.
-    this[kHeadersList].delete(name, false)
+    this.#headersList.delete(name, false)
   }
 
   // https://fetch.spec.whatwg.org/#dom-headers-get
@@ -454,7 +454,7 @@ class Headers {
 
     // 2. Return the result of getting name from this’s header
     //    list.
-    return this[kHeadersList].get(name, false)
+    return this.#headersList.get(name, false)
   }
 
   // https://fetch.spec.whatwg.org/#dom-headers-has
@@ -477,7 +477,7 @@ class Headers {
 
     // 2. Return true if this’s header list contains name;
     //    otherwise false.
-    return this[kHeadersList].contains(name, false)
+    return this.#headersList.contains(name, false)
   }
 
   // https://fetch.spec.whatwg.org/#dom-headers-set
@@ -518,16 +518,14 @@ class Headers {
     // 6. Otherwise, if this’s guard is "response" and name is a
     //    forbidden response-header name, return.
     // Note: undici does not implement forbidden header names
-    if (this[kGuard] === 'immutable') {
+    if (this.#guard === 'immutable') {
       throw new TypeError('immutable')
-    } else if (this[kGuard] === 'request-no-cors') {
-      // TODO
     }
 
     // 7. Set (name, value) in this’s header list.
     // 8. If this’s guard is "request-no-cors", then remove
     //    privileged no-CORS request headers from this
-    this[kHeadersList].set(name, value, false)
+    this.#headersList.set(name, value, false)
   }
 
   // https://fetch.spec.whatwg.org/#dom-headers-getsetcookie
@@ -538,7 +536,7 @@ class Headers {
     // 2. Return the values of all headers in this’s header list whose name is
     //    a byte-case-insensitive match for `Set-Cookie`, in order.
 
-    const list = this[kHeadersList].cookies
+    const list = this.#headersList.cookies
 
     if (list) {
       return [...list]
@@ -549,8 +547,8 @@ class Headers {
 
   // https://fetch.spec.whatwg.org/#concept-header-list-sort-and-combine
   get [kHeadersSortedMap] () {
-    if (this[kHeadersList][kHeadersSortedMap]) {
-      return this[kHeadersList][kHeadersSortedMap]
+    if (this.#headersList[kHeadersSortedMap]) {
+      return this.#headersList[kHeadersSortedMap]
     }
 
     // 1. Let headers be an empty list of headers with the key being the name
@@ -559,14 +557,14 @@ class Headers {
 
     // 2. Let names be the result of convert header names to a sorted-lowercase
     //    set with all the names of the headers in list.
-    const names = this[kHeadersList].toSortedArray()
+    const names = this.#headersList.toSortedArray()
 
-    const cookies = this[kHeadersList].cookies
+    const cookies = this.#headersList.cookies
 
     // fast-path
     if (cookies === null || cookies.length === 1) {
       // Note: The non-null assertion of value has already been done by `HeadersList#toSortedArray`
-      return (this[kHeadersList][kHeadersSortedMap] = names)
+      return (this.#headersList[kHeadersSortedMap] = names)
     }
 
     // 3. For each name of names:
@@ -596,16 +594,38 @@ class Headers {
     }
 
     // 4. Return headers.
-    return (this[kHeadersList][kHeadersSortedMap] = headers)
+    return (this.#headersList[kHeadersSortedMap] = headers)
   }
 
   [util.inspect.custom] (depth, options) {
     options.depth ??= depth
 
-    return `Headers ${util.formatWithOptions(options, this[kHeadersList].entries)}`
+    return `Headers ${util.formatWithOptions(options, this.#headersList.entries)}`
+  }
+
+  static getHeadersGuard (o) {
+    return o.#guard
+  }
+
+  static setHeadersGuard (o, guard) {
+    o.#guard = guard
+  }
+
+  static getHeadersList (o) {
+    return o.#headersList
+  }
+
+  static setHeadersList (o, list) {
+    o.#headersList = list
   }
 }
 
+const { getHeadersGuard, setHeadersGuard, getHeadersList, setHeadersList } = Headers
+Reflect.deleteProperty(Headers, 'getHeadersGuard')
+Reflect.deleteProperty(Headers, 'setHeadersGuard')
+Reflect.deleteProperty(Headers, 'getHeadersList')
+Reflect.deleteProperty(Headers, 'setHeadersList')
+
 Object.defineProperty(Headers.prototype, util.inspect.custom, {
   enumerable: false
 })
@@ -631,8 +651,12 @@ webidl.converters.HeadersInit = function (V, prefix, argument) {
 
     // A work-around to ensure we send the properly-cased Headers when V is a Headers object.
     // Read https://github.com/nodejs/undici/pull/3159#issuecomment-2075537226 before touching, please.
-    if (!util.types.isProxy(V) && kHeadersList in V && iterator === Headers.prototype.entries) { // Headers object
-      return V[kHeadersList].entriesList
+    if (!util.types.isProxy(V) && iterator === Headers.prototype.entries) { // Headers object
+      try {
+        return getHeadersList(V).entriesList
+      } catch {
+        // fall-through
+      }
     }
 
     if (typeof iterator === 'function') {
@@ -654,5 +678,9 @@ module.exports = {
   // for test.
   compareHeaderName,
   Headers,
-  HeadersList
+  HeadersList,
+  getHeadersGuard,
+  setHeadersGuard,
+  setHeadersList,
+  getHeadersList
 }

lib/web/fetch/request.js

@@ -3,7 +3,7 @@
 'use strict'
 
 const { extractBody, mixinBody, cloneBody } = require('./body')
-const { Headers, fill: fillHeaders, HeadersList } = require('./headers')
+const { Headers, fill: fillHeaders, HeadersList, setHeadersGuard, getHeadersGuard, setHeadersList, getHeadersList } = require('./headers')
 const { FinalizationRegistry } = require('./dispatcher-weakref')()
 const util = require('../../core/util')
 const nodeUtil = require('node:util')
@@ -25,10 +25,10 @@ const {
   requestDuplex
 } = require('./constants')
 const { kEnumerableProperty } = util
-const { kHeaders, kSignal, kState, kGuard, kDispatcher } = require('./symbols')
+const { kHeaders, kSignal, kState, kDispatcher } = require('./symbols')
 const { webidl } = require('./webidl')
 const { URLSerializer } = require('./data-url')
-const { kHeadersList, kConstruct } = require('../../core/symbols')
+const { kConstruct } = require('../../core/symbols')
 const assert = require('node:assert')
 const { getMaxListeners, setMaxListeners, getEventListeners, defaultMaxListeners } = require('node:events')
 
@@ -445,8 +445,8 @@ class Request {
     // Realm, whose header list is request’s header list and guard is
     // "request".
     this[kHeaders] = new Headers(kConstruct)
-    this[kHeaders][kHeadersList] = request.headersList
-    this[kHeaders][kGuard] = 'request'
+    setHeadersList(this[kHeaders], request.headersList)
+    setHeadersGuard(this[kHeaders], 'request')
 
     // 31. If this’s request’s mode is "no-cors", then:
     if (mode === 'no-cors') {
@@ -459,13 +459,13 @@ class Request {
       }
 
       // 2. Set this’s headers’s guard to "request-no-cors".
-      this[kHeaders][kGuard] = 'request-no-cors'
+      setHeadersGuard(this[kHeaders], 'request-no-cors')
     }
 
     // 32. If init is not empty, then:
     if (initHasKey) {
       /** @type {HeadersList} */
-      const headersList = this[kHeaders][kHeadersList]
+      const headersList = getHeadersList(this[kHeaders])
       // 1. Let headers be a copy of this’s headers and its associated header
       // list.
       // 2. If init["headers"] exists, then set headers to init["headers"].
@@ -519,7 +519,7 @@ class Request {
       // 3, If Content-Type is non-null and this’s headers’s header list does
       // not contain `Content-Type`, then append `Content-Type`/Content-Type to
       // this’s headers.
-      if (contentType && !this[kHeaders][kHeadersList].contains('content-type', true)) {
+      if (contentType && !getHeadersList(this[kHeaders]).contains('content-type', true)) {
         this[kHeaders].append('content-type', contentType)
       }
     }
@@ -785,7 +785,7 @@ class Request {
     }
 
     // 4. Return clonedRequestObject.
-    return fromInnerRequest(clonedRequest, ac.signal, this[kHeaders][kGuard])
+    return fromInnerRequest(clonedRequest, ac.signal, getHeadersGuard(this[kHeaders]))
   }
 
   [nodeUtil.inspect.custom] (depth, options) {
@@ -894,8 +894,8 @@ function fromInnerRequest (innerRequest, signal, guard) {
   request[kState] = innerRequest
   request[kSignal] = signal
   request[kHeaders] = new Headers(kConstruct)
-  request[kHeaders][kHeadersList] = innerRequest.headersList
-  request[kHeaders][kGuard] = guard
+  setHeadersList(request[kHeaders], innerRequest.headersList)
+  setHeadersGuard(request[kHeaders], guard)
   return request
 }