Method: OMF::Web::Rack::WebsocketHandler#on_register_data_source

Defined in:
lib/omf-web/rack/websocket_handler.rb

#on_register_data_source(args, context) ⇒ Object 



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# File 'lib/omf-web/rack/websocket_handler.rb', line 56

def on_register_data_source(args, context)
  dsp = find_data_source(args)
  return unless dsp  # should define appropriate exception
  debug "Received registration for datasource proxy '#{dsp}'"
  send_data({type: 'reply', status: 'ok'}.to_json)

  mutex = Mutex.new
  semaphore = ConditionVariable.new
  action_queue = {}

  dsp.on_changed(args['offset']) do |action, rows|
    mutex.synchronize do
      (action_queue[action] ||= []).concat(rows)
      semaphore.signal
    end
  end

  # Send the rows in a separate thread, waiting a bit after the first one arriving
  # to 'bunch' things into more manageable number of messages
  Thread.new do
    begin
      loop do
        # Now lets send them
        mutex.synchronize do
          action_queue.each do |action, rows|
            next if rows.empty?
            debug "Sending '#{action}' message with #{rows.length} rows"
            msg = {
              type: 'datasource_update',
              datasource: dsp.name,
              rows: rows,
              action: action
              #offset: offset
            }
            # http://stackoverflow.com/questions/17022394/convert-string-to-utf8-in-ruby
            send_data(msg.to_json.encode("iso-8859-1").force_encoding("UTF-8"))
            rows.clear
          end

          # wait until there is more to send
          semaphore.wait(mutex)
        end

        # OK, there is something to do, but let's wait a bit, maybe there is more
        sleep MESSAGE_DELAY
      end
    rescue Exception => ex
      error "on_register_data_source - #{ex}"
      debug "#{ex.backtrace.join("\n")}"
    end
  end

end