'use strict'
const { kReadyState, kController, kResponse, kBinaryType, kWebSocketURL } = require('./symbols')
const { states, opcodes } = require('./constants')
const { MessageEvent, ErrorEvent } = require('./events')
/* globals Blob */
/**
* @param {import('./websocket').WebSocket} ws
*/
function isEstablished (ws) {
// If the server's response is validated as provided for above, it is
// said that _The WebSocket Connection is Established_ and that the
// WebSocket Connection is in the OPEN state.
return ws[kReadyState] === states.OPEN
}
/**
* @param {import('./websocket').WebSocket} ws
*/
function isClosing (ws) {
// Upon either sending or receiving a Close control frame, it is said
// that _The WebSocket Closing Handshake is Started_ and that the
// WebSocket connection is in the CLOSING state.
return ws[kReadyState] === states.CLOSING
}
/**
* @param {import('./websocket').WebSocket} ws
*/
function isClosed (ws) {
return ws[kReadyState] === states.CLOSED
}
/**
* @see https://dom.spec.whatwg.org/#concept-event-fire
* @param {string} e
* @param {EventTarget} target
* @param {EventInit | undefined} eventInitDict
*/
function fireEvent (e, target, eventConstructor = Event, eventInitDict) {
// 1. If eventConstructor is not given, then let eventConstructor be Event.
// 2. Let event be the result of creating an event given eventConstructor,
// in the relevant realm of target.
// 3. Initialize event’s type attribute to e.
const event = new eventConstructor(e, eventInitDict) // eslint-disable-line new-cap
// 4. Initialize any other IDL attributes of event as described in the
// invocation of this algorithm.
// 5. Return the result of dispatching event at target, with legacy target
// override flag set if set.
target.dispatchEvent(event)
}
/**
* @see https://websockets.spec.whatwg.org/#feedback-from-the-protocol
* @param {import('./websocket').WebSocket} ws
* @param {number} type Opcode
* @param {Buffer} data application data
*/
function websocketMessageReceived (ws, type, data) {
// 1. If ready state is not OPEN (1), then return.
if (ws[kReadyState] !== states.OPEN) {
return
}
// 2. Let dataForEvent be determined by switching on type and binary type:
let dataForEvent
if (type === opcodes.TEXT) {
// -> type indicates that the data is Text
// a new DOMString containing data
try {
dataForEvent = new TextDecoder('utf-8', { fatal: true }).decode(data)
} catch {
failWebsocketConnection(ws, 'Received invalid UTF-8 in text frame.')
return
}
} else if (type === opcodes.BINARY) {
if (ws[kBinaryType] === 'blob') {
// -> type indicates that the data is Binary and binary type is "blob"
// a new Blob object, created in the relevant Realm of the WebSocket
// object, that represents data as its raw data
dataForEvent = new Blob([data])
} else {
// -> type indicates that the data is Binary and binary type is "arraybuffer"
// a new ArrayBuffer object, created in the relevant Realm of the
// WebSocket object, whose contents are data
dataForEvent = new Uint8Array(data).buffer
}
}
// 3. Fire an event named message at the WebSocket object, using MessageEvent,
// with the origin attribute initialized to the serialization of the WebSocket
// object’s url's origin, and the data attribute initialized to dataForEvent.
fireEvent('message', ws, MessageEvent, {
origin: ws[kWebSocketURL].origin,
data: dataForEvent
})
}
/**
* @see https://datatracker.ietf.org/doc/html/rfc6455
* @see https://datatracker.ietf.org/doc/html/rfc2616
* @see https://bugs.chromium.org/p/chromium/issues/detail?id=398407
* @param {string} protocol
*/
function isValidSubprotocol (protocol) {
// If present, this value indicates one
// or more comma-separated subprotocol the client wishes to speak,
// ordered by preference. The elements that comprise this value
// MUST be non-empty strings with characters in the range U+0021 to
// U+007E not including separator characters as defined in
// [RFC2616] and MUST all be unique strings.
if (protocol.length === 0) {
return false
}
for (const char of protocol) {
const code = char.charCodeAt(0)
if (
code < 0x21 ||
code > 0x7E ||
char === '(' ||
char === ')' ||
char === '<' ||
char === '>' ||
char === '@' ||
char === ',' ||
char === ';' ||
char === ':' ||
char === '\\' ||
char === '"' ||
char === '/' ||
char === '[' ||
char === ']' ||
char === '?' ||
char === '=' ||
char === '{' ||
char === '}' ||
code === 32 || // SP
code === 9 // HT
) {
return false
}
}
return true
}
/**
* @see https://datatracker.ietf.org/doc/html/rfc6455#section-7-4
* @param {number} code
*/
function isValidStatusCode (code) {
if (code >= 1000 && code < 1015) {
return (
code !== 1004 && // reserved
code !== 1005 && // "MUST NOT be set as a status code"
code !== 1006 // "MUST NOT be set as a status code"
)
}
return code >= 3000 && code <= 4999
}
/**
* @param {import('./websocket').WebSocket} ws
* @param {string|undefined} reason
*/
function failWebsocketConnection (ws, reason) {
const { [kController]: controller, [kResponse]: response } = ws
controller.abort()
if (response?.socket && !response.socket.destroyed) {
response.socket.destroy()
}
if (reason) {
fireEvent('error', ws, ErrorEvent, {
error: new Error(reason)
})
}
}
module.exports = {
isEstablished,
isClosing,
isClosed,
fireEvent,
isValidSubprotocol,
isValidStatusCode,
failWebsocketConnection,
websocketMessageReceived
}
