Question

I have the following two methods for a Number model.

def track
  number = sanitize(tracking)

  case determine_type(number)
  when 'UPS'
    tracker = ups.track(:tracking_number => number)
    self.carrier              = Carrier.where(:name => 'UPS').first
    self.service              = tracker.service_type
    self.destination_country  = tracker.destination_country
    self.destination_state    = tracker.destination_state
    self.destination_city     = tracker.destination_city
    self.origin_country       = tracker.origin_country
    self.origin_state         = tracker.origin_state
    self.origin_city          = tracker.origin_city
    self.signature            = tracker.signature_name
    self.scheduled_delivery   = tracker.scheduled_delivery_date
    self.weight               = tracker.weight

    tracker.events.each do |event|
      new_event             = Event.new
      new_event.number      = self
      new_event.city        = event.city
      new_event.state       = event.state
      new_event.postalcode  = event.postal_code if event.postal_code
      new_event.country     = event.country
      new_event.status      = event.name
      new_event.status_code = event.type
      new_event.occured_at  = event.occurred_at

      new_event.save
    end
  end

  save
end

def update_number

  case determine_type(number)
  when 'UPS'
    tracker = ups.track(:tracking_number => tracking)
    self.carrier              = Carrier.where(:name => 'UPS').first
    self.service              = tracker.service_type
    self.destination_country  = tracker.destination_country
    self.destination_state    = tracker.destination_state
    self.destination_city     = tracker.destination_city
    self.origin_country       = tracker.origin_country
    self.origin_state         = tracker.origin_state
    self.origin_city          = tracker.origin_city
    self.signature            = tracker.signature_name
    self.scheduled_delivery   = tracker.scheduled_delivery_date
    self.weight               = tracker.weight

    last_event = self.events.ordered.first.occured_at

    tracker.events.each do |event|
      if last_event and (event.occurred_at > last_event)
        new_event             = Event.new
        new_event.number      = self
        new_event.city        = event.city
        new_event.state       = event.state
        new_event.postalcode  = event.postal_code if event.postal_code
        new_event.country     = event.country
        new_event.status      = event.name
        new_event.status_code = event.type
        new_event.occured_at  = event.occurred_at

        new_event.save
      end
    end
  end
  save
end

As you can see, a lot of code is duplicated. And the problem becomes when I start adding the dozen or so other carriers (FedEx, USPS, DHL, etc)…my Number model gets big and hairy fast.

The only real difference between track and update_number is that update_number as an if comparison around the events to check if the events from the carrier are more recent than the latest events I have stored in the database, using that if last_event and (event.occurred_at > last_event) line.

So how can I clean up this code so my model doesn’t get so fat?

Answer 1

Something about your code doesn’t make sense to me, the organization is a little strange and I don’t have enough context on what your app looks like. The OOP-ish way to accomplish something like this in rails is pretty easy; you could also roll your own Strategy, Adapter, or even a Builder pattern to do this.

But, there is some low hanging fruit, you can refactor your code so the common parts are less obtrusive — this is a little better but, create_events is still very case‘y:

def track
  create_events
end

def update_number
  create_events {|e| last_event and (event.occurred_at > last_event) }
end

def create_events(&block)
  case determine_type(number)
  when 'UPS'
    tracker = ups.track(:tracking_number => tracking)
    self.carrier = Carrier.where(:name => 'UPS').first
    self.assign_tracker(tracker)
  end
  tracker.events.each do |e|
    self.create_event(e) unless (block_given? && !block.call(e))
  end
  save
end

def assign_tracker(tracker)
  self.service              = tracker.service_type
  self.destination_country  = tracker.destination_country
  self.destination_state    = tracker.destination_state
  self.destination_city     = tracker.destination_city
  self.origin_country       = tracker.origin_country
  self.origin_state         = tracker.origin_state
  self.origin_city          = tracker.origin_city
  self.signature            = tracker.signature_name
  self.scheduled_delivery   = tracker.scheduled_delivery_date
  self.weight               = tracker.weight
end

def create_event(event)
  new_event             = Event.new
  new_event.number      = self
  new_event.city        = event.city
  new_event.state       = event.state
  new_event.postalcode  = event.postal_code if event.postal_code
  new_event.country     = event.country
  new_event.status      = event.name
  new_event.status_code = event.type
  new_event.occured_at  = event.occurred_at
  new_event.save
end