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Getting StartedGuidesTechnical Reference

Client

A PubSub client is used to listen for events on a channel and publish messages to a channel.

PubSub Client​

Setting up a PubSub Client​

To create a PubSub client, you will first need to create a SignalWire Realtime-Client. After the SignalWire Client is created, you can access the PubSub client using the pubSub namespace.

import { SignalWire} from "@signalwire/realtime-api";

const client = await SignalWire({ project: "ProjectID Here", token: "Token Here" })

const pubSubClient = client.pubSub;

Methods​

listen​

▸ listen({ event: Callback }): Promise<PubSubEvents>

Listen for events on the specified channel.

Parameters​

params
objectrequired

Object containing the parameters of the method.

params.channels
string[]required

List of channels to listen to.

params.EVENT
Callback

The event to listen to. List of events can be found here. Example event: onMessageReceived.

Returns​

Promise<PubSubEvents>

A promise that resolves to a PubSubEvents object that you can use to view the current state or results of the event.

Example​

import { SignalWire} from "@signalwire/realtime-api";

const client = await SignalWire({ project: "ProjectID Here", token: "Token Here" })

const pubSubClient = client.pubSub;

await pubSubClient.listen({
  channels: ["my-channel"],
  onMessageReceived: (message) => {
    console.log(message);
  }
});

In this example:

  • Import the SignalWire module and initialize a new SignalWire client using your project ID and token.
  • Access the PubSub client from the initialized SignalWire client.
  • Subscribe to the my-channel channel and set up a listener for incoming messages.
  • Log received messages to the console.

publish​

▸ publish(params): Promise<void>

Publish a message into the specified channel.

Parameters​

params
objectrequired

Object containing the parameters of the method.

params.channel
stringrequired

Channel in which to send the message.

params.content
anyrequired

The message to send. This can be any JSON-serializable object.

params.meta
Record<any, any>

Metadata associated with the message. There are no requirements on the content of metadata.

Returns​

Promise<void>

Examples​

Publishing a message as a string:

import { SignalWire } from '@signalwire/realtime-api'

const client = await SignalWire({ project: "ProjectID Here", token: "Token Here" })

const pubSubClient = client.pubSub;

await pubSubClient.publish({
  channel: "my-channel",
  content: "Hello, world."
});

Publishing a message as an object:

import { SignalWire } from '@signalwire/realtime-api'

const client = await SignalWire({ project: "ProjectID Here", token: "Token Here" })

const pubSubClient = client.pubSub;

await pubSubClient.publish({
  channel: "my-channel",
  content: {
    field_one: "value_one",
    field_two: "value_two"
  }
});

Events​

onMessageReceived​

• client.pubSub.listen({ onMessageReceived: Callback })

Emitted when a message is received on a channel. Your event handler will be called with an instance of PubSubMessage.

Parameters​

message
PubSubMessagerequired

The message that has been received. See PubSubMessage.