Class: SimplePubSub::Server

Inherits:
Object
  • Object
show all
Defined in:
lib/simplepubsub.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(raw_reg = 'simplepubsub.xml') ⇒ Server

Returns a new instance of Server.



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# File 'lib/simplepubsub.rb', line 70

def initialize(raw_reg='simplepubsub.xml')


  h = {DWSRegistry: ->{raw_reg}, String: ->{DWSRegistry.new raw_reg}}

  @reg = h[raw_reg.class.to_s.to_sym].call

  # try to read the subscribers
  topics = @reg.get_key 'hkey_apps/simplepubsub/subscription_topics'
  
  @hostname = Socket.gethostname
  @subscribers, @bridges = {'#' => []}, {'#' => {}}     
        
  if topics then
    topics.elements.each do |topic_element|
      topic = topic_element.name
      @subscribers[topic] ||= []
      @subscribers[topic] = topic_element.elements[0].elements.map(&:value)
    end
  end      

  
  all_topics = @reg.get_key 'hkey_apps/simplepubsub/subscription_all_topics'

  if all_topics then
    @subscribers['#'] = all_topics.elements[0].elements.map(&:value)
  end                        
  

  bridge_topics = @reg.get_key 'hkey_apps/simplepubsub/bridge_topics'               
        
  if bridge_topics then
    bridge_topics.elements.each do |topic_element|
      topic = topic_element.name
      @bridges[topic] = topic_element.elements[0].elements.inject({}) do |r,x|
        r.merge({x.name.to_s => x.text('address')})
      end
    end
  end

  bridge_all_topics = @reg.get_key 'hkey_apps/simplepubsub/bridge_all_topics'

  if bridge_all_topics then
    @bridges['#'] = bridge_all_topics.elements[0].elements.inject({}) do |r,x|
      r.merge({x.name.to_s => x.text('address')})
    end
  end
  'done'
end

Instance Attribute Details

#bridges ⇒ Object (readonly)

Returns the value of attribute bridges.



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# File 'lib/simplepubsub.rb', line 68

def bridges
  @bridges
end

#subscribers ⇒ Object (readonly)

Returns the value of attribute subscribers.



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# File 'lib/simplepubsub.rb', line 68

def subscribers
  @subscribers
end

Instance Method Details

#add_bridge(topic, hostname, address) ⇒ Object 



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# File 'lib/simplepubsub.rb', line 213

def add_bridge(topic, hostname, address)
  
  if topic == '#' then

    key = "hkey_apps/simplepubsub/bridge_all_topics/webserver/%s/address" % \
        [hostname]        
  else
    topic.sub!('/','_')
    @bridges[topic] ||= {}

    key = "hkey_apps/simplepubsub/bridge_topics/%s/webserver/%s/address" % \
        [topic, hostname]
  end
  
  @bridges[topic].merge!(hostname => address)      
  @reg.set_key key, address    
end

#bridge_deliver(topic, message, excluded_host = nil) ⇒ Object 



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# File 'lib/simplepubsub.rb', line 246

def bridge_deliver(topic, message, excluded_host=nil)
  
  return 'no matching topic' unless @bridges.has_key? topic
  
  if excluded_host  then
    bridges = @bridges[topic].select{|x| x != excluded_host}
  else
    bridges = @bridges[topic]
  end
  
  bridges.values.each do |address|
    url = "http://%s/do/simplepubsub/bridgepub?topic=%s&hostname=%s&message=%s" % \
        [address, URI.escape(topic), @hostname, URI.escape(message)]
    r = open(url, 'UserAgent' => USER_AGENT)
  end
  'bridge delivered'
end

#delete_bridge(topic, hostname) ⇒ Object 



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# File 'lib/simplepubsub.rb', line 231

def delete_bridge(topic, hostname)
  
  @bridges[topic].delete hostname
  
  if @bridges[topic].empty? and topic != '#' then        
    @bridges.delete_key(topic)
    key = "hkey_apps/simplepubsub/bridge_topics/%s" % [topic]
  else
    key = "hkey_apps/simplepubsub/bridge_topics/%s/webserver/%s/address" % \
        [topic, hostname]                
  end
  
  @reg.delete_key key      
end

#deliver(topic, msg) ⇒ Object 



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# File 'lib/simplepubsub.rb', line 150

def deliver(topic, msg)
  
  topic.sub!('/','_')
  
  if not @subscribers.include?(topic) and \
      not @subscribers.include?('#') then
    return 'no topic subscribers' 
  end
             

  DRb.start_service

  topic_subscribers = @subscribers[topic]
  
  if topic_subscribers then
  
    topic_subscribers.each do |uri|
    
      next if @subscribers['#'].include? uri
      
      Thread.new {
        echo = DRbObject.new nil, uri
        
        begin
          echo.message topic, msg
        rescue DRb::DRbConnError => e             
          
          @subscribers[topic].delete uri
          
          if @subscribers[topic].empty? then
            @subscribers.delete topic 
            key = "hkey_apps/simplepubsub/subscription_topics/%s" % [topic]
          else
            key = "hkey_apps/simplepubsub/subscription_topics/%s/subscribers/%s" % \
                [topic, uri[/[^\/]+$/].sub(':','')]              
          end
          
          @reg.delete_key key
          
        end          
      }
      
    end
  end            

  @subscribers['#'].each do |uri|
    Thread.new {
      echo = DRbObject.new nil, uri
      
      begin
        echo.message topic, msg
      rescue DRb::DRbConnError => e
        
        @subscribers['#'].delete uri
        key = "hkey_apps/simplepubsub/subscription_all_topics/subscribers/%s" % \
              [uri[/[^\/]+$/].sub(':','')]         
        @reg.delete_key key          
      end          
    }

  end
end

#start ⇒ Object 



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# File 'lib/simplepubsub.rb', line 120

def start()
  
  # start up the DRb service
  DRb.start_service 'druby://:59000', self

  # wait for the DRb service to finish before exiting
  DRb.thread.join

  'done'
end

#subscribe(topic, uri) ⇒ Object 



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# File 'lib/simplepubsub.rb', line 131

def subscribe(topic, uri)
  
  topic.sub!('/','_')
  @subscribers[topic] ||= []
  @subscribers[topic] << uri      
  
  # e.g. 'hkey_apps/simplepubsub/subscription_topics/magic/subscribers/niko', 
  #         'druby://niko:353524'
  if topic == '#' then
    key = "hkey_apps/simplepubsub/subscription_all_topics/subscribers/%s" % \
      [uri[/[^\/]+$/].sub(':','')]
  else
    key = "hkey_apps/simplepubsub/subscription_topics/%s/subscribers/%s" % \
      [topic, uri[/[^\/]+$/].sub(':','')]        
  end
  
  @reg.set_key key, uri
end