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Module

x/natsws/src/mod.ts>NatsConnection

WebSocket NATS
nats-io/nats.ws
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interface NatsConnection
import { type NatsConnection } from "https://deno.land/x/natsws@v1.28.0/src/mod.ts";

Properties

optional
info: ServerInfo

ServerInfo to the currently connected server or undefined

services: ServicesAPI

Returns a ServicesAPI which allows you to build services using NATS.

Methods

closed(): Promise<void | Error>

Returns a promise that can be used to monitor if the client closes. The promise can resolve an Error if the reason for the close was an error. Note that the promise doesn't reject, but rather resolves to the error if there was one.

close(): Promise<void>

Close will close the connection to the server. This call will terminate all pending requests and subscriptions. The returned promise resolves when the connection closes.

publish(
subject: string,
payload?: Payload,
options?: PublishOptions,
): void

Publishes the specified data to the specified subject.

publishMessage(msg: Msg): void

Publishes using the subject of the specified message, specifying the data, headers and reply found in the message if any.

respondMessage(msg: Msg): boolean

Replies using the reply subject of the specified message, specifying the data, headers in the message if any.

subscribe(subject: string, opts?: SubscriptionOptions): Subscription

Subscribe expresses interest in the specified subject. The subject may have wildcards. Messages are delivered to the SubOpts#callback | SubscriptionOptions callback if specified. Otherwise, the subscription is an async iterator for Msg.

request(
subject: string,
payload?: Payload,
): Promise<Msg>

Publishes a request with specified data in the specified subject expecting a response before RequestOptions#timeout milliseconds. The api returns a Promise that resolves when the first response to the request is received. If there are no responders (a subscription) listening on the request subject, the request will fail as soon as the server processes it.

requestMany(
subject: string,
payload?: Payload,
opts?: Partial<RequestManyOptions>,
): Promise<AsyncIterable<Msg>>

Publishes a request expecting multiple responses back. Several strategies to determine when the request should stop gathering responses.

flush(): Promise<void>

Returns a Promise that resolves when the client receives a reply from the server. Use of this API is not necessary by clients.

drain(): Promise<void>

Initiates a drain on the connection and returns a promise that resolves when the drain completes and the connection closes.

Drain is an ordered shutdown of the client. Instead of abruptly closing the client, subscriptions are drained, that is messages not yet processed by a subscription are handled before the subscription is closed. After subscriptions are drained it is not possible to create a new subscription. Then all pending outbound messages are sent to the server. Finally, the connection is closed.

isClosed(): boolean

Returns true if the client is closed.

isDraining(): boolean

Returns true if the client is draining.

getServer(): string

Returns the hostport of the server the client is connected to.

status(): AsyncIterable<Status>

Returns an async iterator of Status that may be useful in understanding when the client looses a connection, or reconnects, or receives an update from the cluster among other things.

stats(): Stats

Returns some metrics such as the number of messages and bytes sent and recieved by the client.

jetstreamManager(opts?: JetStreamManagerOptions): Promise<JetStreamManager>

Returns a Promise to a JetStreamManager which allows the client to access Streams and Consumers information.

jetstream(opts?: JetStreamOptions | JetStreamManagerOptions): JetStreamClient

Returns a JetStreamClient which allows publishing messages to JetStream or consuming messages from streams.

rtt(): Promise<number>
reconnect(): Promise<void>

Use of this API is experimental, and it is subject to be removed.

reconnect() enables a client to force a reconnect. A reconnect will disconnect the client, and possibly initiate a reconnect to the cluster. Note that all reconnect caveats apply:

  • If the reconnection policy given to the client doesn't allow reconnects, the connection will close.

  • Messages that are inbound or outbound could be lost.

  • All requests that are in flight will be rejected.

Note that the returned promise will reject if the client is already closed, or if it is in the process of draining. If the client is currently disconnected, this API has no effect, as the client is already attempting to reconnect.