need help with sse streaming of new records, postgresql, rails4

rubyonrails-talk
1

I need to make realtime updates for all subscribers. After creating new record i need to publish it for all subscribers. I found a solution using postgre listen/notify In controller:

def index
  response.headers['Content-Type'] = 'text/event-stream'
  sse = SSE.new(response.stream)
  begin
    Comment.on_change do |data|
      sse.write(data)
    end
  rescue IOError
    # Client Disconnected
  ensure
    sse.close
  end
  render nothing: true
end

``

and model

[...]
after_create :notify_comment_added
[...]
private

def notify_comment_added
  Comment.connection.execute "NOTIFY comments, 'data'"
end

``

class << self
  def on_change
    Comment.connection.execute "LISTEN comments"
    loop do
      Comment.connection.raw_connection.wait_for_notify do |event, pid, comment|
        yield comment
      end
    end
  ensure
    Comment.connection.execute "UNLISTEN comments"
  end
end

``

Problems are

  1. Every listeners occupies a connection to db, and after some clients its reach maximum and i got ActiveRecord timeout

  2. it works only with config.cache_classes = true and config.eager_load = true otherwise servers froze on 1-2nd execution of controller. And its a big pain to restart server after every small change.

Does rails have any another solutions to perform this task?