Question

How can I return errors messages from a cross reference table with multiple records when I trying to create those? I’m trying this:

## activity_set.rb
class ActivitySet < ActiveRecord::Base
  has_many :activity_set_lessons
  has_many :lessons, :through => :activity_set_lessons

  validates :name, :presence => true

  def activity_set_lessons=(data)
    data.each_with_index do |v, i|
      activity_set_lessons.build(
        :lesson_id  => v[:lesson_id],
        :sort_order => i,
        :weight_percentage => v[:weight_percentage]
      )
    end
  end
end

## activity_set_lesson.rb
class ActivitySetLesson < ActiveRecord::Base
  belongs_to :activity_set
  belongs_to :lesson

  validates :lesson_id, :presence => true
  validates_each :weight_percentage do |record, attr, value|
    record.errors.add :base, "woot" if value.blank?
  end
end

This is the request data:

## params[:activity_set]
"activity_set" => {
  "name" => "hshshshs", 
  "keywords" => "", 
  "activity_set_lessons" => [
    {"weight_percentage" => "", "lesson_id"=>"4"}, 
    {"weight_percentage" => "", "lesson_id"=>"5"}
  ]
}

Error messages from @activity_set when I do #save:

{
  "errors":{
    "activity_set_lessons":["is invalid","is invalid"]
  },
  "full_messages":[
     "Activity set lessons is invalid","Activity set lessons is invalid"
  ]
}

I always got the same error message even if I’m adding a custom one in the join table. How can I return a message like: “woot 1 is wrong” or something like that, per validation?.

Thanks.

Answer 1

make use of accepts_nested_attributes_for

## activity_set.rb
class ActivitySet < ActiveRecord::Base
  has_many :activity_set_lessons
  has_many :lessons, :through => :activity_set_lessons

  validates :name, :presence => true

  accepts_nested_attributes_for :activity_set_lessons
end

view will look like

= form_for @activity_set do |f|
  [activity_set form fields ]
  = f.fields_for :activity_set_lessons do |p|
    = p.select :lession_id
    = p.select :weight_percentage