Is it possible to merge publish messages?

[rushikeshkoli03]

Can the publish messages be merged if the client is subscribed to multiple to topics. Examples would be:

1. Producer produces message every second for around 400-500 topics.
2. client is subscribed to around 100 topics
3. So instead of sending 100 publish message every second to the client, could they be merged into an array?

[MegaGM]

Apologies for the delayed response. Of course it's possible.
Here I made a very simplified example of how you could implement message aggregation using middlewares.

// client
!async function doSomethingWithFlushedBuffer() {
  const channel = socket.subscribe('RushikeshWatchingList')
  for await (const data of channel) {
    console.info('RushikeshWatchingList data', data)
  }
}()

// server
const messageBuffer = {}
const bufferableChannels = ['currency1', 'currency2', 'currency3']

agServer.setMiddleware(agServer.MIDDLEWARE_OUTBOUND, async (middlewareStream) => {
  for await (const action of middlewareStream) {
    if (action.type === action.PUBLISH_OUT) {
      const { socket, channel, data } = action

      if (!bufferableChannels.includes(channel)) {
        action.allow()
        continue
      }

      if (!messageBuffer[socket.id]) {
        messageBuffer[socket.id] = []
      }
      messageBuffer[socket.id].push({ channel, data })
      action.block(`Message has been buffered`)

      if (messageBuffer[socket.id].length <= 500) {
        continue
      }

      agServer.exchange.transmitPublish('RushikeshWatchingList', messageBuffer[socket.id])
      delete messageBuffer[socket.id]
      // Message buffer has been flushed
    }
  }
})

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