Node.js - websocket.send()

Send a message to a connected websocket client.

import { websocket } from '@nitric/sdk'

const socket = websocket('socket')

/**
 * Send a message to a connected client.
 *
 * @param connectionId the client received when connecting to the websocket
 * @param message to send to the client
 */
const sendMessage = async (connectionId, message) => {
  await socket.send(connectionId, message)
}

Parameters

Name
connectionId
Required
Required
Type
string
Description
The ID of the connection which should receive the message.
Name
message
Required
Required
Type
string | Uint8Array | Record<string, any>
Description
The message that should be sent to the connection.

Examples

Broadcasting a message to all connections.

Do not send messages to a connection during it's connect callback, if you need to acknowledge connection, do so by using a topic

import { websocket, collection } from '@nitric/sdk'

const socket = websocket('socket')
const connections = collection('connections').for(
  'reading',
  'writing',
  'deleting',
)

socket.on('connect', async (ctx) => {
  await connections.doc(ctx.req.connectionId).set({
    // store any metadata related to the connection here
    connectionId: ctx.req.connectionId,
  })
})

socket.on('disconnect', async (ctx) => {
  await connections.doc(ctx.req.connectionId).delete()
})

const broadcast = async (data) => {
  const connectionStream = connections.query().stream()

  const streamEnd = new Promise()((res) => {
    connectionStream.on('end', res)
  })

  connectionStream.on('data', async ({ content }) => {
    // Send message to a connection
    await socket.send(content.connectionId, data)
  })

  await streamEnd
}

socket.on('message', async (ctx) => {
  // broadcast message to all clients (including the sender)
  await broadcast(ctx.req.data)
})