How to call a class method in \lib from model in rails? -

i'm trying generate stats character created form. user inputs name, race, class, alignment, , whether or not stats generated randomly, or prioritized (values being assigned highest lowest). form works flawlessly, can see output in view.

what trying call method class in /lib in model generate stats; however, keep getting following error (i can't post pictures):

nomethoderror in characterscontroller#create    undefined method `[]' nil:nilclass   extracted source (around line #14):    12  before_save 13      generate_stats 14      self.strength = @character_stats[:strength] 15      self.dexterity = @character_stats[:dexterity] 16      self.constitution = @character_stats[:constitution] 17      self.intelligence = @character_stats[:intelligence] 

here copy of of code:

in controllers\characters_controller.rb

class characterscontroller < applicationcontroller     def create         @character = character.new(character_info_params)         @character.name = params[:character][:name].capitalize          @character.alignment = "#{params[:character][:alignment_lr]} #{params[:character][:alignment_ud]}"           if @character.save             redirect_to @character         else             render 'new'         end     end     private      def character_info_params         params.require(:character).permit(:name, :race, :class_, :alignment)     end end 

in models\character.rb

class character < activerecord::base     require 'random_stats_generator'         attr_accessor :rand_stat_gen      def generate_stats         if @rand_stat_gen == true             @character_stats_inst = randomstatgenerator.new             @character_stats = @character_stats_inst.generate         end     end      before_save         generate_stats         self.strength = @character_stats[:strength]         self.dexterity = @character_stats[:dexterity]         self.constitution = @character_stats[:constitution]         self.intelligence = @character_stats[:intelligence]         self.wisdom = @character_stats[:wisdom]         self.charisma = @character_stats[:charisma]     end  #validation passed point  end 

in initializers\stat_builders.rb

require "./lib/random_stat_generator.rb" 

in lib/random_stat_generator.rb

class randomstatgenerator      def initialize         @strength = :strength         @dexterity = :dexterity         @constitution = :constitution         @intelligence = :intelligence         @wisdom = :wisdom         @charisma = :charisma         @character_stats = hashwithindifferentaccess.new()     end      def self.generate         roll_stats     end      def roll(stat)         @roll_value_1 = (1 + (rand(6)))         @roll_value_2 = (1 + (rand(6)))         @roll_value_3 = (1 + (rand(6)))         @roll_value_4 = (1 + (rand(6)))         @roll_array = [@roll_value_1,@roll_value_2,@roll_value_3,@roll_value_4]         @roll_array = @roll_array.sort_by {|x| x }         @roll_array = @roll_array.reverse         stat = @roll_array[0] + @roll_array[1] + @roll_array[2]     end      def roll_stats         @strength = roll(@strength)         @dexterity = roll(@dexterity)         @constitution = roll(@constitution)         @intelligence = roll(@intelligence)         @wisdom = roll(@wisdom)         @charisma = roll(@charisma)          @character_stats[:strength] = @strength         @character_stats[:dexterity] = @dexterity         @character_stats[:constitution] = @constitution         @character_stats[:intelligence] = @intelligence         @character_stats[:wisdom] = @wisdom         @character_stats[:charisma] = @charisma          return @character_stats     end end 

to me, looks method isn't returning anything, or isn't being called @ all.

i've tried lot of solutions i've come across online, none of them working. there may things don't make sense left on these solutions. i'm starting rails, i'm still trying used everything.

thanks lot help.

ruby has powerful functions manipulating both hashes , arrays. typing out duplicate assignments like:

self.strength = @character_stats[:strength] self.dexterity = @character_stats[:dexterity] self.constitution = @character_stats[:constitution] 

is pretty dull. instead can rewrite methods pass hashes around.

class randomstatgenerator    # constant containing stats want generate.   stats = [:strength, :dexterity, :constitution, :intelligence, :wisdom, :charisma]    # create hash random roll values each stat   def self.roll_stats     # kind of scary looking creates      # hash array of keys     hash[stats.map {|k| [k, self.roll ] } ]   end    private    def self.roll     # create array 4 elements (nil)      ary = array.new(4)     # replace nil value random value 1-6     ary = ary.map        (1 + (rand(6)))     end     # sort , drop lowest roll. return sum of rolls.     ary.sort.drop(1).sum      # ruby ninja writes     array.new(4).map { 1 + rand(6) }.sort.drop(1).sum   end end 

output:

irb(main):032:0> randomstatgenerator.roll_stats => {:strength=>14, :dexterity=>14, :constitution=>14, :intelligence=>13, :wisdom=>10, :charisma=>9} 

but if don't intend create instances of class, should use module instead.

rails models can either created hash or can replace values hash:

character.new(randomstatgenerator.roll_stats) @character.assign_attributes(randomstatgenerator.roll_stats) 

so can use in character#generate_stats:

def generate_stats   assign_attributes(randomstatgenerator.roll_stats) end 

you should use activemodel callbacks extreme prejudice. quite challenge regulate in application , when in model lifetime. since before_save runs after validations means validations validates_presence_of :constitution fail.

in case might better in controller or use:

before_validation :generate_stats, if: -> { new_record? && @rand_stat_gen }