feat: init

node_modules/undici/lib/web/eventsource/eventsource.js

@@ -0,0 +1,480 @@
+'use strict'
+
+const { pipeline } = require('node:stream')
+const { fetching } = require('../fetch')
+const { makeRequest } = require('../fetch/request')
+const { getGlobalOrigin } = require('../fetch/global')
+const { webidl } = require('../fetch/webidl')
+const { EventSourceStream } = require('./eventsource-stream')
+const { parseMIMEType } = require('../fetch/data-url')
+const { MessageEvent } = require('../websocket/events')
+const { isNetworkError } = require('../fetch/response')
+const { delay } = require('./util')
+const { kEnumerableProperty } = require('../../core/util')
+
+let experimentalWarned = false
+
+/**
+ * A reconnection time, in milliseconds. This must initially be an implementation-defined value,
+ * probably in the region of a few seconds.
+ *
+ * In Comparison:
+ * - Chrome uses 3000ms.
+ * - Deno uses 5000ms.
+ *
+ * @type {3000}
+ */
+const defaultReconnectionTime = 3000
+
+/**
+ * The readyState attribute represents the state of the connection.
+ * @enum
+ * @readonly
+ * @see https://html.spec.whatwg.org/multipage/server-sent-events.html#dom-eventsource-readystate-dev
+ */
+
+/**
+ * The connection has not yet been established, or it was closed and the user
+ * agent is reconnecting.
+ * @type {0}
+ */
+const CONNECTING = 0
+
+/**
+ * The user agent has an open connection and is dispatching events as it
+ * receives them.
+ * @type {1}
+ */
+const OPEN = 1
+
+/**
+ * The connection is not open, and the user agent is not trying to reconnect.
+ * @type {2}
+ */
+const CLOSED = 2
+
+/**
+ * Requests for the element will have their mode set to "cors" and their credentials mode set to "same-origin".
+ * @type {'anonymous'}
+ */
+const ANONYMOUS = 'anonymous'
+
+/**
+ * Requests for the element will have their mode set to "cors" and their credentials mode set to "include".
+ * @type {'use-credentials'}
+ */
+const USE_CREDENTIALS = 'use-credentials'
+
+/**
+ * @typedef {object} EventSourceInit
+ * @property {boolean} [withCredentials] indicates whether the request
+ * should include credentials.
+ */
+
+/**
+ * The EventSource interface is used to receive server-sent events. It
+ * connects to a server over HTTP and receives events in text/event-stream
+ * format without closing the connection.
+ * @extends {EventTarget}
+ * @see https://html.spec.whatwg.org/multipage/server-sent-events.html#server-sent-events
+ * @api public
+ */
+class EventSource extends EventTarget {
+  #events = {
+    open: null,
+    error: null,
+    message: null
+  }
+
+  #url = null
+  #withCredentials = false
+
+  #readyState = CONNECTING
+
+  #request = null
+  #controller = null
+
+  /**
+   * @type {object}
+   * @property {string} lastEventId
+   * @property {number} reconnectionTime
+   * @property {any} reconnectionTimer
+   */
+  #settings = null
+
+  /**
+   * Creates a new EventSource object.
+   * @param {string} url
+   * @param {EventSourceInit} [eventSourceInitDict]
+   * @see https://html.spec.whatwg.org/multipage/server-sent-events.html#the-eventsource-interface
+   */
+  constructor (url, eventSourceInitDict = {}) {
+    // 1. Let ev be a new EventSource object.
+    super()
+
+    webidl.argumentLengthCheck(arguments, 1, { header: 'EventSource constructor' })
+
+    if (!experimentalWarned) {
+      experimentalWarned = true
+      process.emitWarning('EventSource is experimental, expect them to change at any time.', {
+        code: 'UNDICI-ES'
+      })
+    }
+
+    url = webidl.converters.USVString(url)
+    eventSourceInitDict = webidl.converters.EventSourceInitDict(eventSourceInitDict)
+
+    // 2. Let settings be ev's relevant settings object.
+    // https://html.spec.whatwg.org/multipage/webappapis.html#environment-settings-object
+    this.#settings = {
+      origin: getGlobalOrigin(),
+      policyContainer: {
+        referrerPolicy: 'no-referrer'
+      },
+      lastEventId: '',
+      reconnectionTime: defaultReconnectionTime
+    }
+
+    let urlRecord
+
+    try {
+      // 3. Let urlRecord be the result of encoding-parsing a URL given url, relative to settings.
+      urlRecord = new URL(url, this.#settings.origin)
+      this.#settings.origin = urlRecord.origin
+    } catch (e) {
+      // 4. If urlRecord is failure, then throw a "SyntaxError" DOMException.
+      throw new DOMException(e, 'SyntaxError')
+    }
+
+    // 5. Set ev's url to urlRecord.
+    this.#url = urlRecord.href
+
+    // 6. Let corsAttributeState be Anonymous.
+    let corsAttributeState = ANONYMOUS
+
+    // 7. If the value of eventSourceInitDict's withCredentials member is true,
+    // then set corsAttributeState to Use Credentials and set ev's
+    // withCredentials attribute to true.
+    if (eventSourceInitDict.withCredentials) {
+      corsAttributeState = USE_CREDENTIALS
+      this.#withCredentials = true
+    }
+
+    // 8. Let request be the result of creating a potential-CORS request given
+    // urlRecord, the empty string, and corsAttributeState.
+    const initRequest = {
+      redirect: 'follow',
+      keepalive: true,
+      // @see https://html.spec.whatwg.org/multipage/urls-and-fetching.html#cors-settings-attributes
+      mode: 'cors',
+      credentials: corsAttributeState === 'anonymous'
+        ? 'same-origin'
+        : 'omit',
+      referrer: 'no-referrer'
+    }
+
+    // 9. Set request's client to settings.
+    initRequest.client = this.#settings
+
+    // 10. User agents may set (`Accept`, `text/event-stream`) in request's header list.
+    initRequest.headersList = [['accept', { name: 'accept', value: 'text/event-stream' }]]
+
+    // 11. Set request's cache mode to "no-store".
+    initRequest.cache = 'no-store'
+
+    // 12. Set request's initiator type to "other".
+    initRequest.initiator = 'other'
+
+    initRequest.urlList = [new URL(this.#url)]
+
+    // 13. Set ev's request to request.
+    this.#request = makeRequest(initRequest)
+
+    this.#connect()
+  }
+
+  /**
+   * Returns the state of this EventSource object's connection. It can have the
+   * values described below.
+   * @returns {0|1|2}
+   * @readonly
+   */
+  get readyState () {
+    return this.#readyState
+  }
+
+  /**
+   * Returns the URL providing the event stream.
+   * @readonly
+   * @returns {string}
+   */
+  get url () {
+    return this.#url
+  }
+
+  /**
+   * Returns a boolean indicating whether the EventSource object was
+   * instantiated with CORS credentials set (true), or not (false, the default).
+   */
+  get withCredentials () {
+    return this.#withCredentials
+  }
+
+  #connect () {
+    if (this.#readyState === CLOSED) return
+
+    this.#readyState = CONNECTING
+
+    const fetchParam = {
+      request: this.#request
+    }
+
+    // 14. Let processEventSourceEndOfBody given response res be the following step: if res is not a network error, then reestablish the connection.
+    const processEventSourceEndOfBody = (response) => {
+      if (isNetworkError(response)) {
+        this.dispatchEvent(new Event('error'))
+        this.close()
+      }
+
+      this.#reconnect()
+    }
+
+    // 15. Fetch request, with processResponseEndOfBody set to processEventSourceEndOfBody...
+    fetchParam.processResponseEndOfBody = processEventSourceEndOfBody
+
+    // and processResponse set to the following steps given response res:
+    fetchParam.processResponse = (response) => {
+      // 1. If res is an aborted network error, then fail the connection.
+
+      if (isNetworkError(response)) {
+        // 1. When a user agent is to fail the connection, the user agent
+        // must queue a task which, if the readyState attribute is set to a
+        // value other than CLOSED, sets the readyState attribute to CLOSED
+        // and fires an event named error at the EventSource object. Once the
+        // user agent has failed the connection, it does not attempt to
+        // reconnect.
+        if (response.aborted) {
+          this.close()
+          this.dispatchEvent(new Event('error'))
+          return
+          // 2. Otherwise, if res is a network error, then reestablish the
+          // connection, unless the user agent knows that to be futile, in
+          // which case the user agent may fail the connection.
+        } else {
+          this.#reconnect()
+          return
+        }
+      }
+
+      // 3. Otherwise, if res's status is not 200, or if res's `Content-Type`
+      // is not `text/event-stream`, then fail the connection.
+      const contentType = response.headersList.get('content-type', true)
+      const mimeType = contentType !== null ? parseMIMEType(contentType) : 'failure'
+      const contentTypeValid = mimeType !== 'failure' && mimeType.essence === 'text/event-stream'
+      if (
+        response.status !== 200 ||
+        contentTypeValid === false
+      ) {
+        this.close()
+        this.dispatchEvent(new Event('error'))
+        return
+      }
+
+      // 4. Otherwise, announce the connection and interpret res's body
+      // line by line.
+
+      // When a user agent is to announce the connection, the user agent
+      // must queue a task which, if the readyState attribute is set to a
+      // value other than CLOSED, sets the readyState attribute to OPEN
+      // and fires an event named open at the EventSource object.
+      // @see https://html.spec.whatwg.org/multipage/server-sent-events.html#sse-processing-model
+      this.#readyState = OPEN
+      this.dispatchEvent(new Event('open'))
+
+      // If redirected to a different origin, set the origin to the new origin.
+      this.#settings.origin = response.urlList[response.urlList.length - 1].origin
+
+      const eventSourceStream = new EventSourceStream({
+        eventSourceSettings: this.#settings,
+        push: (event) => {
+          this.dispatchEvent(new MessageEvent(
+            event.type,
+            event.options
+          ))
+        }
+      })
+
+      pipeline(response.body.stream,
+        eventSourceStream,
+        (error) => {
+          if (
+            error?.aborted === false
+          ) {
+            this.close()
+            this.dispatchEvent(new Event('error'))
+          }
+        })
+    }
+
+    this.#controller = fetching(fetchParam)
+  }
+
+  /**
+   * @see https://html.spec.whatwg.org/multipage/server-sent-events.html#sse-processing-model
+   * @returns {Promise<void>}
+   */
+  async #reconnect () {
+    // When a user agent is to reestablish the connection, the user agent must
+    // run the following steps. These steps are run in parallel, not as part of
+    // a task. (The tasks that it queues, of course, are run like normal tasks
+    // and not themselves in parallel.)
+
+    // 1. Queue a task to run the following steps:
+
+    //   1. If the readyState attribute is set to CLOSED, abort the task.
+    if (this.#readyState === CLOSED) return
+
+    //   2. Set the readyState attribute to CONNECTING.
+    this.#readyState = CONNECTING
+
+    //   3. Fire an event named error at the EventSource object.
+    this.dispatchEvent(new Event('error'))
+
+    // 2. Wait a delay equal to the reconnection time of the event source.
+    await delay(this.#settings.reconnectionTime)
+
+    // 5. Queue a task to run the following steps:
+
+    //   1. If the EventSource object's readyState attribute is not set to
+    //      CONNECTING, then return.
+    if (this.#readyState !== CONNECTING) return
+
+    //   2. Let request be the EventSource object's request.
+    //   3. If the EventSource object's last event ID string is not the empty
+    //      string, then:
+    //      1. Let lastEventIDValue be the EventSource object's last event ID
+    //         string, encoded as UTF-8.
+    //      2. Set (`Last-Event-ID`, lastEventIDValue) in request's header
+    //         list.
+    if (this.#settings.lastEventId !== '') {
+      this.#request.headersList.set('last-event-id', this.#settings.lastEventId, true)
+    }
+
+    //   4. Fetch request and process the response obtained in this fashion, if any, as described earlier in this section.
+    this.#connect()
+  }
+
+  /**
+   * Closes the connection, if any, and sets the readyState attribute to
+   * CLOSED.
+   */
+  close () {
+    webidl.brandCheck(this, EventSource)
+
+    if (this.#readyState === CLOSED) return
+    this.#readyState = CLOSED
+    clearTimeout(this.#settings.reconnectionTimer)
+    this.#controller.abort()
+
+    if (this.#request) {
+      this.#request = null
+    }
+  }
+
+  get onopen () {
+    return this.#events.open
+  }
+
+  set onopen (fn) {
+    if (this.#events.open) {
+      this.removeEventListener('open', this.#events.open)
+    }
+
+    if (typeof fn === 'function') {
+      this.#events.open = fn
+      this.addEventListener('open', fn)
+    } else {
+      this.#events.open = null
+    }
+  }
+
+  get onmessage () {
+    return this.#events.message
+  }
+
+  set onmessage (fn) {
+    if (this.#events.message) {
+      this.removeEventListener('message', this.#events.message)
+    }
+
+    if (typeof fn === 'function') {
+      this.#events.message = fn
+      this.addEventListener('message', fn)
+    } else {
+      this.#events.message = null
+    }
+  }
+
+  get onerror () {
+    return this.#events.error
+  }
+
+  set onerror (fn) {
+    if (this.#events.error) {
+      this.removeEventListener('error', this.#events.error)
+    }
+
+    if (typeof fn === 'function') {
+      this.#events.error = fn
+      this.addEventListener('error', fn)
+    } else {
+      this.#events.error = null
+    }
+  }
+}
+
+const constantsPropertyDescriptors = {
+  CONNECTING: {
+    __proto__: null,
+    configurable: false,
+    enumerable: true,
+    value: CONNECTING,
+    writable: false
+  },
+  OPEN: {
+    __proto__: null,
+    configurable: false,
+    enumerable: true,
+    value: OPEN,
+    writable: false
+  },
+  CLOSED: {
+    __proto__: null,
+    configurable: false,
+    enumerable: true,
+    value: CLOSED,
+    writable: false
+  }
+}
+
+Object.defineProperties(EventSource, constantsPropertyDescriptors)
+Object.defineProperties(EventSource.prototype, constantsPropertyDescriptors)
+
+Object.defineProperties(EventSource.prototype, {
+  close: kEnumerableProperty,
+  onerror: kEnumerableProperty,
+  onmessage: kEnumerableProperty,
+  onopen: kEnumerableProperty,
+  readyState: kEnumerableProperty,
+  url: kEnumerableProperty,
+  withCredentials: kEnumerableProperty
+})
+
+webidl.converters.EventSourceInitDict = webidl.dictionaryConverter([
+  { key: 'withCredentials', converter: webidl.converters.boolean, defaultValue: false }
+])
+
+module.exports = {
+  EventSource,
+  defaultReconnectionTime
+}