Class: OMF::Web::Rack::WebsocketHandler

Inherits:
Rack::WebSocket::Application
  • Object
show all
Extended by:
Common::Loggable
Includes:
Common::Loggable
Defined in:
lib/omf-web/rack/websocket_handler.rb

Constant Summary collapse

MESSAGE_DELAY = 
0.5

Instance Method Summary collapse

Methods included from Common::Loggable

_logger, debug, error, fatal, info, init_log, logger, set_environment, warn

Instance Method Details

#find_data_source(args) ⇒ Object 



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# File 'lib/omf-web/rack/websocket_handler.rb', line 145

def find_data_source(args)
  ds_name = args['ds_name']
  unless dsp = OMF::Web::DataSourceProxy[ds_name]
    warn "Request for unknown datasource '#{ds_name}'."
    send_data({type: 'reply', status: 'error', err_msg: "Unknown datasource '#{ds_name}'"}.to_json)
    return nil
  end
  dsp
end

#on_close(env) ⇒ Object 



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# File 'lib/omf-web/rack/websocket_handler.rb', line 45

def on_close(env)
  begin
    debug "client disconnected"
    @tab_inst.on_ws_close(self, @sub_path) if @tab_inst
    @tab_inst = nil
  rescue Exception => ex
    error(ex)
  end
end

#on_message(env, msg_s) ⇒ Object 



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# File 'lib/omf-web/rack/websocket_handler.rb', line 20

def on_message(env, msg_s)
  begin
    req = ::Rack::Request.new(env)
    sid = req.params['sid']
    Thread.current["sessionID"] = sid

    msg = JSON.parse(msg_s)
    debug("Msg(#{sid}): #{msg.inspect}")
    msg_type = msg['type']
    args = msg['args']
    msg_handler = "on_#{msg_type}".to_sym
    unless respond_to? msg_handler
      warn "Received unknonw request '#{msg_type}'"
      send_data({type: 'reply', status: 'error', err_msg: "Unknown message type '#{msg_type}'"}.to_json)
      return
    end
    context = OMF::Web::SessionStore[args['name'], :ws] ||= {}
    send(msg_handler, args, context)
  rescue Exception => ex
    error ex
    debug "#{ex.backtrace.join("\n")}"
    send_data({type: 'reply', status: 'exception', err_msg: ex.to_s}.to_json)
  end
end

#on_open(env) ⇒ Object

Delay in pushing action message to browser after receiving a ‘on_change’ from monitored data proxy



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# File 'lib/omf-web/rack/websocket_handler.rb', line 16

def on_open(env)
  #puts ">>>>> OPEN"
end

#on_register_data_source(args, context) ⇒ Object 



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# File 'lib/omf-web/rack/websocket_handler.rb', line 55

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
            }
            send_data(msg.to_json)
            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

#on_request_slice(args, context) ⇒ Object

args “col_value”=>“e8…”, “ds_name”=>“individual_link”}}



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# File 'lib/omf-web/rack/websocket_handler.rb', line 109

def on_request_slice(args, context)
  dsp = find_data_source(args)
  return unless dsp  # should define appropriate exception
  
  sargs = args['slice']
  col_name = sargs['col_name']
  col_value = sargs['col_value']
  debug "Creating slice '#{col_name}:#{col_value}' data source '#{dsp}'"
  
  if old_sdsp = context[:sliced_datasource]
    return if old_sdsp[:column_name] == col_name
    old_sdsp[:dsp].release
  end
  sdsp = dsp.create_slice(col_name, col_value)
  context[:sliced_datasource] = {:col_name => col_name, :dsp => sdsp}
  sdsp.on_changed(0) do |action, rows|
    msg = {
      type: 'datasource_update',
      datasource: args['ds_name'],
      rows: rows,
      action: action
      #offset: offset
    }
    send_data(msg.to_json)
#         
    # do |new_rows, offset|
    # msg = {
      # type: 'datasource_update',
      # datasource: args['ds_name'],
      # rows: new_rows,
      # offset: offset
    # }
    # send_data(msg.to_json)
  end
end