Class WebSocketTransport

src/utils/mcpWebSocketTransport.ts:22–200

}

export class WebSocketTransport implements Transport {
  private started = false
  private opened: Promise<void>
  private isBun = typeof Bun !== 'undefined'

  constructor(private ws: WebSocketLike) {
    this.opened = new Promise((resolve, reject) => {
      if (this.ws.readyState === WS_OPEN) {
        resolve()
      } else if (this.isBun) {
        const nws = this.ws as unknown as globalThis.WebSocket
        const onOpen = () => {
          nws.removeEventListener('open', onOpen)
          nws.removeEventListener('error', onError)
          resolve()
        }
        const onError = (event: Event) => {
          nws.removeEventListener('open', onOpen)
          nws.removeEventListener('error', onError)
          logForDiagnosticsNoPII('error', 'mcp_websocket_connect_fail')
          reject(event)
        }
        nws.addEventListener('open', onOpen)
        nws.addEventListener('error', onError)
      } else {
        const nws = this.ws as unknown as WsWebSocket
        nws.on('open', () => {
          resolve()
        })
        nws.on('error', error => {
          logForDiagnosticsNoPII('error', 'mcp_websocket_connect_fail')
          reject(error)
        })
      }
    })

    // Attach persistent event handlers
    if (this.isBun) {
      const nws = this.ws as unknown as globalThis.WebSocket
      nws.addEventListener('message', this.onBunMessage)
      nws.addEventListener('error', this.onBunError)
      nws.addEventListener('close', this.onBunClose)
    } else {
      const nws = this.ws as unknown as WsWebSocket
      nws.on('message', this.onNodeMessage)
      nws.on('error', this.onNodeError)
      nws.on('close', this.onNodeClose)
    }
  }

  onclose?: () => void
  onerror?: (error: Error) => void
  onmessage?: (message: JSONRPCMessage) => void

  // Bun (native WebSocket) event handlers
  private onBunMessage = (event: MessageEvent) => {
    try {
      const data =