@service-broker/client-node

Node ESM client library for interacting with a service broker

Install

npm install @service-broker/client-node

Connect

const sb = new ServiceBroker({
  // websocket URL of the service broker
  url: string,
  // if the service-broker requires providers to authenticate when advertising
  authToken?: string,
  // callback for when connection is established (or re-established)
  onConnect?: () => void,
  // disable auto-reconnect function (upon connect failure or connection loss)
  disableAutoReconnect?: boolean,
  // whether to send websocket pings periodically
  keepAliveIntervalSeconds?: number,
  // logger for info and errors
  logger?: Logger,
})

Advertise

sb.advertise(
  service: {name: string, capabilities?: string[], priority?: number},
  handler: (req: Message) => Message|Promise<Message>
)

A service provider calls this method to advertise to the broker the service(s) it provides. For explanation of parameters, see service broker.

Request

sb.request(
  service: {name: string, capabilities?: string[]},
  req: Message,
  timeout?: number
)
: Promise<Message>

A client calls this method to request some service. The broker will select a qualified provider based on service name and capabilities. The parameter req contains the actual message that'll be delivered to the service provider (see handler in Advertise). The returned promise contains the response from the provider.

RequestTo

sb.requestTo(
  endpointId: string,
  serviceName: string,
  req: Message,
  timeout?: number
)
: Promise<Message>

Send a request directly to an endpoint.

Notify

sb.notify(
  service: {name: string, capabilities?: string[]},
  msg: Message
)

A notification is a request without an id, and thus no response will be generated. Use a notification when you don't care about the result.

NotifyTo

sb.notifyTo(
  endpointId: string,
  serviceName: string,
  msg: Message
)

Send a notification directly to an endpoint.

Publish/Subscribe

sb.publish(
  topic: string,
  text: string
)

sb.subscribe(
  topic: string,
  handler: (text: string) => void
)

SetServiceHandler

sb.setServiceHandler(
  serviceName: string,
  handler: (req: Message) => Message|Promise<Message>
)

This installs a handler for a particular service without advertising the it to the broker. This is for when the client knows the provider's endpointId and can send the request directly to it (see RequestTo).

Status

sb.status(): Promise<any>

Returns the service broker's status, which includes the list of services and service providers currently active.

WaitEndpoint

sb.waitEndpoint(endpointId: string): Promise<void>

Returns a promise that resolves when the specified endpoint disconnects.

Shutdown

sb.shutdown()

Close the connection to the service broker.