How do i specify and validate an enum in rails?

Question

I currently have a model Attend that will have a status column, and this status column will only have a few values for it. STATUS_OPTIONS = {:yes, :no, :maybe}

1)

Answer 1

After some looking, I could not find a one-liner in model to help it happen. By now, Rails provides Enums, but not a comprehensive way to validate invalid values.

So, I opted for a composite solution: To add a validation in the controller, before setting the strong_params, and then by checking against the model.

So, in the model, I will create an attribute and a custom validation:

attend.rb

enum :status => { your set of values }
attr_accessor :invalid_status

validate :valid_status
#...
private
    def valid_status
        if self.invalid_status == true
            errors.add(:status, "is not valid")
        end
    end

Also, I will do a check against the parameters for invalid input and send the result (if necessary) to the model, so an error will be added to the object, thus making it invalid

attends_controller.rb

private
    def attend_params
        #modify strong_params to include the additional check
        if params[:attend][:status].in?(Attend.statuses.keys << nil) # to also allow nil input
            # Leave this as it was before the check
            params.require(:attend).permit(....) 
        else
            params[:attend][:invalid_status] = true
            # remove the 'status' attribute to avoid the exception and
            # inject the attribute to the params to force invalid instance
            params.require(:attend).permit(...., :invalid_status)
       end
    end