Function createWebSocketServer

packages/vite/src/node/server/ws.ts:118–467

(
  server: HttpServer | null,
  config: ResolvedConfig,
  httpsOptions?: HttpsServerOptions,
)

}

export function createWebSocketServer(
  server: HttpServer | null,
  config: ResolvedConfig,
  httpsOptions?: HttpsServerOptions,
): WebSocketServer {
  if (config.server.ws === false) {
    return {
      [isWebSocketServer]: true,
      get clients() {
        return new Set<WebSocketClient>()
      },
      async close() {
        // noop
      },
      on: noop as any as WebSocketServer['on'],
      off: noop as any as WebSocketServer['off'],
      setInvokeHandler: noop,
      handleInvoke: async () => ({
        error: {
          name: 'TransportError',
          message: 'handleInvoke not implemented',
          stack: new Error().stack,
        },
      }),
      listen: noop,
      send: noop,
    }
  }

  let wsHttpServer: Server | undefined = undefined

  const wsOptions = isObject(config.server.ws) ? config.server.ws : undefined
  const wsCustomServer = wsOptions?.server
  const wsPort = wsOptions?.port
  // TODO: the main server port may not have been chosen yet as it may use the next available
  const portsAreCompatible = !wsPort || wsPort === config.server.port
  const wsServer = wsCustomServer || (portsAreCompatible && server)
  let hmrServerWsListener: (
    req: InstanceType<typeof IncomingMessage>,
    socket: Duplex,
    head: Buffer,
  ) => void
  const customListeners = new Map<string, Set<WebSocketCustomListener<any>>>()
  const clientsMap = new WeakMap<WebSocketRaw, WebSocketClient>()
  const port = wsPort || 24678
  const host = wsOptions?.host || undefined
  const allowedHosts =
    config.server.allowedHosts === true
      ? config.server.allowedHosts
      : Object.freeze([...config.server.allowedHosts]) // Freeze the array to allow caching

  const shouldHandle = (req: IncomingMessage) => {
    const protocol = req.headers['sec-websocket-protocol']!
    // vite-ping is allowed to connect from anywhere
    // because it needs to be connected before the client fetches the new `/@vite/client`
    // this is fine because vite-ping does not receive / send any meaningful data
    if (protocol === 'vite-ping') return true