Not getting any value back from function defined in controller - ruby-on-rails

Question

This is my controller. def random_generate is not giving me any output, and when I create the object, length is there but random_primer_generated is empty. Can someone help me?
class GeneratorsController < ApplicationController
before_action :set_generator, only: [:show, :edit, :update, :destroy]
helper_method :random_generate
# GET /generators
# GET /generators.json
def index
#generators = Generator.all
end
# GET /generators/1
# GET /generators/1.json
def show
end
# GET /generators/new
def new
#generator = Generator.new
end
# GET /generators/1/edit
def edit
end
# POST /generators
# POST /generators.json
def create
#generator = Generator.new(generator_params)
respond_to do |format|
if #generator.save
format.html { redirect_to #generator, notice: 'Generator was successfully created.' }
format.json { render action: 'show', status: :created, location: #generator }
else
format.html { render action: 'new' }
format.json { render json: #generator.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /generators/1
# PATCH/PUT /generators/1.json
def update
respond_to do |format|
if #generator.update(generator_params)
format.html { redirect_to #generator, notice: 'Generator was successfully updated.' }
format.json { head :no_content }
else
format.html { render action: 'edit' }
format.json { render json: #generator.errors, status: :unprocessable_entity }
end
end
end
# DELETE /generators/1
# DELETE /generators/1.json
def destroy
#generator.destroy
respond_to do |format|
format.html { redirect_to generators_url }
format.json { head :no_content }
end
end
def random_generate
if #generator.choice == 'Randomly'
length = #generator.primer_length
chars = 'atgc'
seq = ''
#length = length.to_i
length.times { seq << chars[rand(chars.size)] }
#generator.random_primer_generated = seq
end
return #generator.random_primer_generated
end
private
# Use callbacks to share common setup or constraints between actions.
def set_generator
#generator = Generator.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def generator_params
params.require(:generator).permit(:primer_length, :choice_random_primer_generated)
end
end
This is my Form_VIEW (to get the user's data - length and choice):
<%= form_for (#generator ) do |f| %>
<% if #generator.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#generator.errors.count, "error") %> prohibited this generator from being saved:</h2>
<ul>
<% #generator.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<label>Primer Length</label><br>
<%= f.number_field :primer_length %>
</div>
<label>Selection :</label><br>
<label>Randomly</label>
<%= radio_button_tag(:choice_random_primer_generated, 'Randomly')%>
<%= button_to('Generate', random_generate_generator_path(#generator))%>
<% end %>

Answer 1

Note: the form may be a red herring here. If you only want the code to be randomly generated when the user explicitly clicks that button, and NOT after every create or save, then you don't want any callbacks. You're doing it the right way. The only thing you are missing is the save call at the end of your method, and you'll also want to redirect the user back to a page.
However, if you DO want generate to happen after EVERY create or update, then you should probably change that button_to call to f.submit, and move that random_generate code to your model. Then, you can use rails callback for after_save and call that method from there within your controller.
More info:
http://guides.rubyonrails.org/active_record_callbacks.html

Answer 2

You are not calling your helper_method anywhere. When you post the form and it reaches the server, the create method is called. The helper_method is not triggered, therefore you are not creating a random number.
I didn't understand it very well, but what are you trying to randomize? Why don't you simply use a rand(999) to randomize numbers for example?

Answer 3

It looks like you want to call random_generate after your new and create action, but you are not calling it. All you have to do is change helper_method :random_generate to after_action :random_generate, only: [:create, :new]
You also want to make sure to save your new record in random_generate. You don't need the return #genator.random_primer_generated. See below:
def random_generate
if #generator.choice == 'Randomly'
length = #generator.primer_length
chars = 'atgc'
seq = ''
#length = length.to_i
length.times { seq << chars[rand(chars.size)] }
#generator.random_primer_generated = seq
end
#generator.save!
end