Method: SMQueue::StompAdapter#get

Defined in:
lib/smqueue/adapters/stomp.rb

#get(headers = {}, &block) ⇒ Object

get message from queue

  • if block supplied, loop forever and yield(message) for each message received

default headers are:

:ack               => "client"
:client_id         => configuration.client_id
:subscription_name => configuration.subscription_name



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# File 'lib/smqueue/adapters/stomp.rb', line 250

def get(headers = {}, &block)
  self.connect
  SMQueue.dbg { [:smqueue, :get, headers].inspect }
  subscription_headers = {"ack" => "client", "activemq.prefetchSize" => 1 }
  if client_id = configuration.client_id
    subscription_headers["client_id"] = client_id
  end
  if sub_name = configuration.subscription_name
    subscription_headers["subscription_name"] = sub_name
  end
  # if a client_id is supplied, then user wants a durable subscription
  # N.B. client_id must be unique for broker
  subscription_headers.update(headers)
  #p [:subscription_headers_before, subscription_headers]
  subscription_headers = normalize_keys(subscription_headers)
  if configuration.durable and client_id = configuration.client_id || subscription_headers["client_id"]
    subscription_name = configuration.subscription_name || subscription_headers["subscription_name"] || client_id
    # activemq only
    subscription_headers["activemq.subscriptionName"] = subscription_name
    # JMS
    subscription_headers["durable-subscriber-name"] = subscription_name
  end
  #p [:subscription_headers_after, subscription_headers]
  
  destination = configuration.name
  SMQueue.dbg { [:smqueue, :get, :subscribing, destination, :subscription_headers, subscription_headers].inspect }
  connection.subscribe destination, subscription_headers
  message = nil
  SMQueue.dbg { [:smqueue, :get, :subscription_headers, subscription_headers].inspect }
  begin
    # TODO: refactor this
    if block_given?
      SMQueue.dbg { [:smqueue, :get, :block_given].inspect }
      # todo: change to @running - (and set to false from exception handler)
      # also should check to see if anything left to receive on connection before bailing out
      while true
        SMQueue.dbg { [:smqueue, :get, :receive].inspect }
        # block until message ready
        message = connection.receive
        SMQueue.dbg { [:smqueue, :get, :received, message].inspect }
        case message.command
        when "ERROR"
          SMQueue.dbg { [:smqueue, :get, :ERROR, message].inspect }
        when "RECEIPT"
          SMQueue.dbg { [:smqueue, :get, :RECEIPT, message].inspect }
        else
          SMQueue.dbg { [:smqueue, :get, :yielding].inspect }
          if !message_seen?(message.headers["message-id"])
            yield(message)
          end
          SMQueue.dbg { [:smqueue, :get, :message_seen, message.headers["message-id"]].inspect }
          message_seen message.headers["message-id"]
          SMQueue.dbg { [:smqueue, :get, :returned_from_yield_now_calling_ack].inspect }
          ack(subscription_headers, message)
          SMQueue.dbg { [:smqueue, :get, :returned_from_ack].inspect }
        end
      end
    else
      SMQueue.dbg { [:smqueue, :get, :single_shot].inspect }
      message = connection.receive
      SMQueue.dbg { [:smqueue, :get, :received, message].inspect }
      if !(message.command == "ERROR" or message.command == "RECEIPT")
        SMQueue.dbg { [:smqueue, :get, :message_seen, message.headers["message-id"]].inspect }
        message_seen message.headers["message-id"]
        SMQueue.dbg { [:smqueue, :get, :ack, message].inspect }
        ack(subscription_headers, message)
        SMQueue.dbg { [:smqueue, :get, :returned_from_ack].inspect }
      end
    end
  rescue Object => e
    SMQueue.dbg { [:smqueue, :get, :exception, e].inspect }
    handle_error e, "Exception in SMQueue#get: #{e.message}", caller
  ensure
    SMQueue.dbg { [:smqueue, :get, :ensure].inspect }
    SMQueue.dbg { [:smqueue, :unsubscribe, destination, subscription_headers].inspect }
    connection.unsubscribe destination, subscription_headers
    SMQueue.dbg { [:smqueue, :disconnect].inspect }
    connection.disconnect
  end
  SMQueue.dbg { [:smqueue, :get, :return].inspect }
  message
end