Variable access in rails stream

Question

I am creating a web slide show application where one “wizard” can move between slides and all browsers follow it. For this, I use websockets and Redis for the global channel to send messages. Each client that connects, is there information that is stored in an array @clients. Then I have a separate thread for subscribing to the Redis channel, in which there is a specific block "on.message", which should send a message to everyone in the array @clients, but this array is empty inside this block (not empty somewhere else in the module).

Pretty much following this example: https://devcenter.heroku.com/articles/ruby-websockets

Relevant code that resides in the middleware user class:

require 'faye/websocket'
require 'redis'

class WsCommunication
  KEEPALIVE_TIME = 15 #seconds
  CHANNEL = 'vip-deck'

  def initialize(app)
    @app = app
    @clients = []

    uri = URI.parse(ENV['REDISCLOUD_URL'])
    Thread.new do
      redis_sub = Redis.new(host: uri.host, port: uri.port, password: uri.password)
      redis_sub.subscribe(CHANNEL) do |on|
        on.message do |channel, msg|
          puts @clients.count
          ### prints '0,' no clients receive msg
          @clients.each { |ws| ws.send(msg) }
        end
      end
    end
  end

  def call(env)
    if Faye::WebSocket.websocket?(env)
    ws = Faye::WebSocket.new(env, nil, {ping: KEEPALIVE_TIME})

    ws.on :open do |event|
      @clients << ws
      puts @clients.count
      ### prints actual number of clients
    end

    ws.on :message do |event|
      $redis.publish(CHANNEL, event.data)
    end

    ws.on :close do |event|
      @clients.delete(ws)
      ws = nil
    end

    ws.rack_response
  else
    @app.call(env)
  end
end
end

Is an array @clientsempty when accessing it inside a new thread because instance variables are not shared between threads? and if so, how do I share a variable by thread?

I also tried using $ clients (global variable, should be accessible through streams), to no avail.

EDIT: man this site is so full of boasts. no one else responds, they just make super minor changes to get a reputation.

Answer 1

: . , . . , , .

. , .

config/application.rb , , - :

require 'ws_communication'
config.middleware.use WsCommunication

JavaScript- - :

var ws = new WebSocket(uri);

WsCommunication? @clients . - :

var ws = new WsCommunication;

, , , config/application.rb, .

, , @clients , . , . redis-mutex - . (, , , , 500 .)

, $redis.publish , .

, , , . , , , - , . , , "", , . , " ", . , on.message, .

, , :

require 'faye/websocket'
require 'redis'

class WsCommunication
  KEEPALIVE_TIME = 15 #seconds
  CHANNEL = 'vip-deck'

  def initialize(app)
    @app = app
    @clients = []
    uri = URI.parse(ENV['REDISCLOUD_URL'])
    $redis = Redis.new(host: uri.host, port: uri.port, password: uri.password)
    Thread.new do
      redis_sub = Redis.new(host: uri.host, port: uri.port, password: uri.password)
      redis_sub.subscribe(CHANNEL) do |on|
        on.message do |channel, msg|
          puts "Message event. Clients receiving:#{@clients.count};"
          @clients.each { |ws| ws.send(msg) }
        end
      end
    end
  end

  def call(env)
    if Faye::WebSocket.websocket?(env)
      ws = Faye::WebSocket.new(env, nil, {ping: KEEPALIVE_TIME})

      ws.on :open do |event|
        @clients << ws
        puts "Open event. Clients open:#{@clients.count};"
      end

      ws.on :message do |event|
        receivers = $redis.publish(CHANNEL, event.data)
        puts "Message published:#{event.data}; Receivers:#{receivers};"
      end

      ws.on :close do |event|
        @clients.delete(ws)
        puts "Close event. Clients open:#{@clients.count};"
        ws = nil
      end

      ws.rack_response
    else
      @app.call(env)
    end
  end
end

, :

# encoding: UTF-8
puts "Starting client-subscriber.rb"
$:.unshift File.expand_path '../lib', File.dirname(__FILE__)
require 'rubygems'
require 'eventmachine'
require 'websocket-client-simple'

puts "websocket-client-simple v#{WebSocket::Client::Simple::VERSION}"

url = ARGV.shift || 'ws://localhost:3000'

EM.run do

  ws = WebSocket::Client::Simple.connect url

  ws.on :message do |msg|
    puts msg
  end

  ws.on :open do
    puts "-- Subscriber open (#{ws.url})"
  end

  ws.on :close do |e|
    puts "-- Subscriber close (#{e.inspect})"
    exit 1
  end

  ws.on :error do |e|
    puts "-- Subscriber error (#{e.inspect})"
  end

end

, . , :

# encoding: UTF-8
puts "Starting client-publisher.rb"
$:.unshift File.expand_path '../lib', File.dirname(__FILE__)
require 'rubygems'
require 'eventmachine'
require 'json'
require 'websocket-client-simple'

puts "websocket-client-simple v#{WebSocket::Client::Simple::VERSION}"

url = ARGV.shift || 'ws://localhost:3000'

EM.run do
  count ||= 0
  timer = EventMachine.add_periodic_timer(5+rand(5)) do
    count += 1
    send({"MESSAGE": "COUNT:#{count};"})
  end

  @ws = WebSocket::Client::Simple.connect url

  @ws.on :message do |msg|
    puts msg
  end

  @ws.on :open do
    puts "-- Publisher open"
  end

  @ws.on :close do |e|
    puts "-- Publisher close (#{e.inspect})"
    exit 1
  end

  @ws.on :error do |e|
    puts "-- Publisher error (#{e.inspect})"
    @ws.close
  end

  def self.send message
    payload = message.is_a?(Hash) ? message : {payload: message}
    @ws.send(payload.to_json)
  end
end

config.ru, :

require './controllers/main'
require './middlewares/ws_communication'
use WsCommunication
run Main.new

Main. , , :

%w(rubygems bundler sinatra/base json erb).each { |m| require m }
ENV['RACK_ENV'] ||= 'development'
Bundler.require
$: << File.expand_path('../', __FILE__)
$: << File.expand_path('../lib', __FILE__)

Dir["./lib/*.rb", "./lib/**/*.rb"].each { |file| require file }
env = ENV['OS'] == 'Windows_NT' ? 'development' : ENV['RACK_ENV']

  class Main < Sinatra::Base

    env = ENV['OS'] == 'Windows_NT' ? 'development' : ENV['RACK_ENV']
    get "/" do
      erb :"index.html"
    end

    get "/assets/js/application.js" do
      content_type :js
      @scheme = env == "production" ? "wss://" : "ws://"
      erb :"application.js"
    end
  end

Answer 2

@client , , ? " " ws.on: close . , @client : http://ruby-doc.org/core-2.2.0/Mutex.html