Class: SPSSub

Inherits:
Object
  • Object
show all
Defined in:
lib/sps-sub.rb

Instance Method Summary collapse

Constructor Details

#initialize(hosts: [], port: '59000', host: nil, address: nil, callback: nil) ⇒ SPSSub

Returns a new instance of SPSSub.



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# File 'lib/sps-sub.rb', line 10

def initialize(hosts: [], port: '59000', host: nil, address: nil, callback: nil )

  if host.nil? and address.nil? and hosts.any? then
    hostx, portx = hosts.first.split(':',2)
    portx ||= port
    @host, @port = hostx, portx
  else
    @host = host || address || 'localhost'
    @port = port.to_s
  end
  
  @callback = callback
  @retry_interval = 1
  @hosts = hosts
  
  # Trap ^C 
  Signal.trap("INT") { 
    puts ' ... Bye'
    @status = :quit
    exit
  }
  
  # Trap `Kill `
  Signal.trap("TERM") {
    @status = :quit
    exit
  }    
  
end

Instance Method Details

#em_connect(topic, &blk) ⇒ Object 



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# File 'lib/sps-sub.rb', line 55

def em_connect(topic, &blk)
  
  client = self
  host, port = @host, @port 
  
  EM.run do

    address = host + ':' + port

    @ws = ws = WebSocket::EventMachine::Client.connect(:uri => 'ws://' + address)

    ws.onopen do
      puts "Connected"
    end

    ws.onmessage do |fqm, type|
      
      topic, msg = fqm.split(/:\s/,2)
      
      EM.defer do
        
        if block_given? then
          blk.call(msg, topic)
        elsif @callback
          @callback.ontopic(topic, msg)
        else
          onmessage msg
          ontopic topic, msg
        end
        
      end
              
    end

    ws.onclose do
      puts "Disconnected"

      return if @status == :quit
      
      if @hosts.any? then
        
        hostx, portx = @hosts.rotate!.first.split(':',2)
        portx ||= @port
        @host, @port = hostx, portx
        client.em_connect topic
        
      else
        @retry_interval *= 2        
        sleep @retry_interval        
        @retry_interval = 1 if @retry_interval > 30
  
        puts "retrying to connect to #{@host}:#{@port}... "
        client.em_connect topic
      end
    end
    
    ws.onerror do |error|
      puts "Error occured: #{error}"
    end

    EventMachine.next_tick do
      ws.send 'subscribe to topic: ' + topic
    end

  end    
end

#notice(s) ⇒ Object 



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# File 'lib/sps-sub.rb', line 40

def notice(s)
  
  EventMachine.next_tick do
    @ws.send s
  end    
  
end

#onmessage(msg) ⇒ Object

This method is called when a new message is received



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# File 'lib/sps-sub.rb', line 124

def onmessage(msg)
  puts "Received message: #{msg}"
end

#ontopic(topic, msg) ⇒ Object

Same as onmessage but includes the topic as well as the msg



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# File 'lib/sps-sub.rb', line 130

def ontopic(topic, msg)

end

#subscribe(topic: '#', &blk) ⇒ Object 



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# File 'lib/sps-sub.rb', line 48

def subscribe(topic: '#', &blk)
  
  @t = Time.now

  em_connect(topic, &blk)
end