threads.ruby

conf.ru

require "rack"
require "json"

use Rack::ContentLength
use Rack::Logger, Logger.new(STDOUT)
use Rack::Static, :urls => ["/static"]

module CacheHolder
  CACHE = Hash.new
  LOCK = Mutex.new

  def self.get(key)
    LOCK.synchronize do
      CACHE.fetch(key, nil)
    end
  end

  def self.set(key, value)
    LOCK.synchronize do
      CACHE[key] = value
    end
  end

  def self.get_cache_key(request)
    "#{request['type']}//#{request['SERVER_PROTOCOL']}//#{'->' * 3}"
  end

end

class Responder

  def initialize(env)
    @request = Rack::Request.new(env)
    @param = @request['type']
  end

  def try_get_value
    time = Random.rand(0.5)
    p "Sleeping #{time}. sec"
    sleep time
    key = CacheHolder.get_cache_key(@request)
    value = CacheHolder.get(key)
    if value.nil?
      value = get_value_slow
      CacheHolder.set(key, value)
    end
    value
  end

  def get_value_slow
    time = Random.rand(10)
    p "Sleeping #{time}. sec"
    sleep time
    "#{'#' * 1000}"
  end

  def each
    @body = { param: @param, value: try_get_value }
    yield @body.to_json
  end
end

app = proc do |env|
  [ 200, {'Content-Type' => 'text/json' }, Responder.new(env) ]
end

run app

snippet.js

request = function() {
    'use strict';
    return Promise.all([
        $.getJSON('http://localhost:9292/', { type: 'documents' }), 
        $.getJSON('http://localhost:9292/', { type: 'projects' }), 
    ]).then(function(res) {
        if (res[0].param !== 'documents' || res[1].param !== 'projects') {
            console.log('race ->', res[0].context, res[1].context )
        }
    });
}

Promise.all(_.times(100, request)).then(()=> { console.log('done') })