ruby-on-rails - 在此 Controller /模型设置中如何显示错误？

Question

我有一个create方法，该方法在ping某些第三方API的模型中调用一个方法。

我需要做的是，如果API发送回一定的消息，那么我会显示一个错误。

下面是我当前的 Controller 和模型设置，那么如何将错误重新输入到 Controller (最终是 View )中？

这是我的 Controller 中的方法:

def create
  @number = Number.where(:tracking => params[:number][:tracking], :user_id => current_user.id).first

  if @number.blank?
    @number = Number.new
    @number.tracking = params[:number][:tracking]
    @number.user_id = current_user.id
    @number.notes = params[:number][:notes]
    @number.track
  end

  respond_with(@number) do |format|  
    format.html { redirect_to root_path }  
  end
end

这是我模型中的方法:

def track
  create_events
end


def create_events(&block)

  tracker = fedex.track(:tracking_number => number)

  if tracker.valid?    
    self.assign_tracker(tracker)

    tracker.events.each do |e|
      self.create_event(e) unless (block_given? && !block.call(e))
    end

    save
  else
    # NEED TO THROW THE ERROR HERE
  end
end

Answer 1

如果只使用验证而不是抛出错误呢？类似于以下内容(只需开始即可。这需要工作。):

# if you don't cache the tracker in an attribute already, do this so
# you can add errors as if it were a column.
attr_accessor :tracker

def create_events(&block)

  tracker = fedex.track(:tracking_number => number)

  if tracker.valid?    
    # ...
  else
    # add the error with i18n
    errors.add(:tracker, :error_type_if_you_know_it)

    # or add it from a returned message
    errors.add(:tracker, nil, :message => fedex.get_error())
  end
end

然后在您的 Controller 中:

@number.track

respond_with(@number) do |format|
  if @number.errors.any?
    format.html { redirect_to root_path }
  else
    format.html { render :some_template_with_errors }
  end
end

也可以使用作为验证的一部分(因此，调用valid?将按预期工作，并且不会破坏您的自定义“跟踪”错误)

# do your tracking on creation, if number was given
validate :on => :create do
  if number.present?
    tracker = fedex.track(:tracking_number => number)
    unless tracker.valid?
      errors.add :tracker, nil, :message => tracker.get_error()
    end
  end
end

# then do your actual creation of tracking events sometime after validation
before_save :handle_tracker_assignment

def handle_tracker_assignment
  self.assign_tracker(tracker)
  # note the block method you're using would need to be reworked
  # ...
end

请注意，在后一种情况下，您必须稍微更改逻辑，只需传递跟踪编号并尝试保存新记录，这将触发跟踪尝试。