验证：在 Rails Controller 中使用自定义方法

Question

I want to do a put/patch to the following route which in return calls the bars controller and calls its update_premium method: put '/bar/premium', to: 'bars#update_premium'

However that method should call a validation check in the model itself whenever.save or.valid?/.valid is called.

bar.rb

class Bar < ApplicationRecord
    belongs_to :city
    validate :validate_premium_bars, on: :create
    validate :validate_premium_bars, on: :update_premium

    def allow
        @allow_change = true
    end

    private
    def validate_premium_bars
        return unless self.city
        unless @allow_change
            if self.city.bars.where(:is_premium => true).count >= 5
                errors.add("...")
            end
        end
    end
end

bars_controller.rb

def update_premium
        @bar = Bar.find(params[:id])
        if @bar.save
            ...
        else
            render json: @bar.errors.full_messages, status: 400
        end
end

It works when I use on: :update however a custom method in the controller such as on: :update_premium doesn't work together with the "on:" symbol.

How can I resolve this? I want to keep the update method in the controller for a real full model update and not just for triggering one attribute of the model.

Answer 1

Considering the situation in this question I would actually suggest just adding validation as:

validate :validate_premium_bars

So it runs every time you run valid? or save is called instead of adding specific conditions for create and update .

In case, you want to add this separately for some reason. You can add the validation to run for update and update the actual attribute using the update call or call valid? on it after value check to make sure that the record passes validations

Answer 2

The problem is that the update controller action is no mapped to the model actions. One refers to an endpoint and the other refers to an event in the model lifecycle. Looks at the official documentation about validation options.

You can create a custom conditional validation to run each time the model is changed. For example:

  validate :validate_premium_bars, if: :allowed_chage?
 
  def allowed_chage?
    @allowed_chage
  end

soruce