When amber and imba collid in harmony to generate server side event (SSE)

particules

-- imba part:


tag App
  def build
    messages

  def messages
      console.log('messages')
      @last_event_id = "0"
      @evtSource =  EventSource.new "/messages/live?last_event_id={@last_event_id}"
     
      @messages = [] 
      @evtSource:onmessage = do |e|
        console.log(e) 
        let message = JSON.parse(e:data)
        console.log(message) 
        @messages.push({name: message:name, content: message:content})
        Imba.commit

  def render
    <self>
      <div.messages> 
        "Messages" 
        for message in @messages
          <Message[message]>

Imba.mount <App>



-- amber part 

class MessageController < ApplicationController
  def live
    response.headers["Content-Type"] = "text/event-stream"
    messages = Message.all.last(10) # where params  ...
    last_event_id = params[:last_event_id] || "0"
    my_json = messages[(last_event_id).to_i+1].to_json
      
"retry: 1000
event: message
id: params[:id]
data: #{my_json}

" if my_json
        
  end

The challenge was to create simple a SSE using blazing fast (still underground) techs.
For the time being, Amber as no internal way to generate SSE in streaming way. This is just a gist, but a more sustainable way would be to only send new info as to block (put on wait) rendering in the live method, until there is new info to render, so even without pure streaming we are still taking advantage of the keep-alive persisting connecting