WebSocket

The WebSocket binding. The emitted member is ws, and every object carries bindingVersion: 0.1.0.

@websocketChannel

extern dec websocketChannel(
  target: Interface | Namespace,
  config: valueof AsyncAPIWebSocketChannelBinding
);

Field	Type	Required
method	string	no
query	unknown	no
headers	unknown	no

Apply it to the interface or namespace that carries @channel or @dynamicChannel.

The emitted member is ws. AsyncAPI names the binding folder websockets, and it names the member ws. The member name is what a reader of the document sees.

method is the HTTP method that opens the connection. AsyncAPI allows GET and POST. Any other value is reported through invalid-binding-field. The field is dropped and the rest of the binding is kept.

query and headers describe the handshake. Each one is a Schema Object. Write it as an object literal of type object with a properties key. AsyncAPI states both requirements. A schema that meets neither describes no parameter, so the emitter reports it and drops the field. A $ref passes without either key, because the schema behind it lives elsewhere.

The WebSocket binding has no server, operation or message object. The specification states that all three must carry no property. So @websocketChannel is the whole protocol.

@websocketChannel(#{
  method: "GET",
  query: #{ type: "object", properties: #{ token: #{ type: "string" } } }
})
@channel("/ticks")
interface TickStream {
  @send
  op publish(event: Tick): void;
}

channels:
  /ticks:
    address: /ticks
    bindings:
      ws:
        method: GET
        query:
          type: object
          properties:
            token:
              type: string
        bindingVersion: 0.1.0