ambition/app/models/comment.rb

class Comment < ActiveRecord::Base
    
    belongs_to :mission
    
    validates :content, presence: true
    validates :mission_id, presence: true
    
    validates :user_id, presence: true
    validate :comment_has_atleast_one_character, on: :create
    validate :user_id_exist, on: :create
    
    private 
    
      
        def comment_has_atleast_one_character
            tmp = content.strip
            if tmp.length < 1
                errors[:content] = 'content should has at least one character'
            end
        end
        
        
        def user_id_exist
            
            user = User.find_by(id: user_id)
            if user == nil
                errors[:user] = "user is not exist"
            end
    
        end
        
        
        # mission 是否存在的验证将放在controller中进行
        
        # def mission_id_should_be_exist
            
        #     @mission = Mission.find(:mission_id)
            
        #     if @mission == nil
        #         errors[:mission_id] = "mission is not exist"
        #     end
        # end    
    
end