Spring WebFlux WebSocket API

asyncapi: 3.0.0
info:
  title: Spring WebFlux WebSocket API
  version: 6.2.0
  description: >-
    AsyncAPI specification describing WebSocket communication patterns for
    Spring WebFlux applications. Spring WebFlux provides reactive WebSocket
    support via WebSocketHandler and WebSocketSession, enabling full-duplex,
    bidirectional messaging between clients and servers.
  license:
    name: Apache 2.0
    url: https://www.apache.org/licenses/LICENSE-2.0
  externalDocs:
    url: https://docs.spring.io/spring-framework/reference/web/webflux-websocket.html
    description: Spring WebFlux WebSocket Documentation

servers:
  production:
    host: '{host}:{port}'
    protocol: ws
    description: Spring WebFlux WebSocket endpoint
    variables:
      host:
        default: localhost
        description: Application host
      port:
        default: '8080'
        description: Application port
  secure:
    host: '{host}:{port}'
    protocol: wss
    description: Secure Spring WebFlux WebSocket endpoint (TLS)
    variables:
      host:
        default: localhost
        description: Application host
      port:
        default: '8443'
        description: Application port

channels:
  websocketSession:
    address: /ws
    description: >-
      WebSocket channel mapped via Spring WebFlux WebSocketHandlerAdapter.
      A WebSocketSession is established on connection and provides reactive
      inbound() and outbound() message streams.
    messages:
      textMessage:
        $ref: '#/components/messages/TextMessage'
      binaryMessage:
        $ref: '#/components/messages/BinaryMessage'
      pingMessage:
        $ref: '#/components/messages/PingMessage'
      pongMessage:
        $ref: '#/components/messages/PongMessage'
      closeMessage:
        $ref: '#/components/messages/CloseMessage'

  stompBroker:
    address: /stomp
    description: >-
      STOMP over WebSocket channel. Spring WebFlux integrates with STOMP messaging
      protocol for topic subscriptions, queued messages, and message broker relay.
    messages:
      stompMessage:
        $ref: '#/components/messages/StompMessage'

operations:
  sendTextMessage:
    action: send
    channel:
      $ref: '#/channels/websocketSession'
    summary: Send Text Message
    description: >-
      Client sends a text message over the WebSocket connection.
      In Spring WebFlux, this corresponds to WebSocketSession.send(publisher).
    messages:
      - $ref: '#/components/messages/TextMessage'

  receiveTextMessage:
    action: receive
    channel:
      $ref: '#/channels/websocketSession'
    summary: Receive Text Message
    description: >-
      Server receives a text message from the client.
      In Spring WebFlux, WebSocketSession.receive() returns a Flux<WebSocketMessage>.
    messages:
      - $ref: '#/components/messages/TextMessage'

  sendBinaryMessage:
    action: send
    channel:
      $ref: '#/channels/websocketSession'
    summary: Send Binary Message
    description: Send a binary data frame over the WebSocket connection.
    messages:
      - $ref: '#/components/messages/BinaryMessage'

  receiveBinaryMessage:
    action: receive
    channel:
      $ref: '#/channels/websocketSession'
    summary: Receive Binary Message
    description: Receive a binary data frame from the WebSocket connection.
    messages:
      - $ref: '#/components/messages/BinaryMessage'

  subscribeToTopic:
    action: send
    channel:
      $ref: '#/channels/stompBroker'
    summary: Subscribe to Topic
    description: STOMP SUBSCRIBE frame to subscribe to a topic or queue.
    messages:
      - $ref: '#/components/messages/StompMessage'

  receiveTopicMessage:
    action: receive
    channel:
      $ref: '#/channels/stompBroker'
    summary: Receive Topic Message
    description: Receive a STOMP MESSAGE frame from a subscribed topic.
    messages:
      - $ref: '#/components/messages/StompMessage'

components:
  messages:
    TextMessage:
      name: TextMessage
      title: WebSocket Text Message
      summary: A UTF-8 encoded text data frame (opcode 0x1)
      contentType: text/plain
      payload:
        $ref: '#/components/schemas/TextPayload'

    BinaryMessage:
      name: BinaryMessage
      title: WebSocket Binary Message
      summary: A binary data frame (opcode 0x2)
      contentType: application/octet-stream
      payload:
        $ref: '#/components/schemas/BinaryPayload'

    PingMessage:
      name: PingMessage
      title: WebSocket Ping Frame
      summary: A control ping frame (opcode 0x9) for keep-alive
      payload:
        $ref: '#/components/schemas/ControlPayload'

    PongMessage:
      name: PongMessage
      title: WebSocket Pong Frame
      summary: A control pong frame (opcode 0xA) in response to ping
      payload:
        $ref: '#/components/schemas/ControlPayload'

    CloseMessage:
      name: CloseMessage
      title: WebSocket Close Frame
      summary: A control close frame (opcode 0x8) to initiate connection closure
      payload:
        $ref: '#/components/schemas/ClosePayload'

    StompMessage:
      name: StompMessage
      title: STOMP Frame
      summary: A STOMP protocol frame for topic messaging over WebSocket
      contentType: application/json
      payload:
        $ref: '#/components/schemas/StompPayload'

  schemas:
    TextPayload:
      type: object
      properties:
        content:
          type: string
          description: UTF-8 text content of the message
        sessionId:
          type: string
          description: WebSocketSession identifier

    BinaryPayload:
      type: object
      properties:
        data:
          type: string
          format: binary
          description: Binary data content

    ControlPayload:
      type: object
      properties:
        applicationData:
          type: string
          description: Optional application data in control frame

    ClosePayload:
      type: object
      properties:
        statusCode:
          type: integer
          description: RFC 6455 close status code (e.g. 1000 Normal Closure)
        reason:
          type: string
          description: Human-readable reason for closure

    StompPayload:
      type: object
      properties:
        command:
          type: string
          enum: [CONNECT, CONNECTED, SUBSCRIBE, UNSUBSCRIBE, SEND, MESSAGE, ACK, NACK, DISCONNECT, ERROR]
          description: STOMP command
        headers:
          type: object
          additionalProperties:
            type: string
          description: STOMP frame headers
        body:
          type: string
          description: STOMP frame body