Question

Objective

Initialize a new addition problem for users to solve when they visit /task. They input their answer, and the form submits back to /task. The new action should initialize the problem, since users cannot edit the problem, only provide an answer. The create action should update the table addition_tasks in the column answer with the user’s submitted answer.

Problem

As I currently have it, the task is created and saved successfully in the new action, but fails to update with the create action.

Model

# == Schema Information
#
# Table name: addition_tasks
#
#  id            :integer         not null, primary key
#  first_addend  :integer
#  second_addend :integer
#  sum           :integer
#  answer        :integer
#  correct       :boolean
#  created_at    :datetime        not null
#  updated_at    :datetime        not null
#

class AdditionTask < ActiveRecord::Base

  attr_accessible :answer

  belongs_to :user
end

Routes

  match 'task', to: 'addition_task#new'
  match 'task', to: 'addition_task#create'

Controller

class AdditionTaskController < ApplicationController

  respond_to :html, :js

  def new
    @task = AdditionTask.new
    @task = new_task(@task)
    @task.save
    session[:task_id] = @task.id
  end

  def create
    @task = AdditionTask.find(session[:task_id])
    @task.answer = params[:addition_task][:answer]
    respond_with :new
  end

  private

  def new_task(task)
    @task.first_addend = 1 + Random.rand(98)
    @task.second_addend = 1 + Random.rand(98)
    @task.sum = @task.first_addend + @task.second_addend
    @task
  end
end

View

%h1 Problem
:markdown
  Please answer the question below. You may press "Enter" from within the answer field, instead of clicking the button, in order to receive a new question.

#task-container
  .addend
    =@task.first_addend
  .operator
    +
  .addend
    =@task.second_addend
  .operator
    \=
  .answer
    =simple_form_for @task, url: task_path, defaults: {input_html: {class: 'span2'}}, html: { class: 'form-inline' } do |f|
      =f.input :answer, label: false
      =f.submit :submit, class: 'btn-primary btn-large pull-right', value: 'Answer'

%div
  =@task.sum

Answer 1

Siwei’s answer and lee’s answer both made excellent points.

Thanks to some folks in #rubyonrails, I moved the code from create to update. I also changed my routes, as Siwei suggested, and saved the object, as lee suggested. However, I used @obj.save! in order to get some helpful errors if something went wrong.

New Routes

  resources :users
  resources :addition_tasks, path: 'task', only: [:new, :update]

  root to: 'site#home'
  match 'signup',  to: 'users#new'
  match 'signin',  to: 'sessions#new'

New Controller

class AdditionTasksController < ApplicationController

  respond_to :html, :js

  def new
    @task = AdditionTask.new
    @task = new_task(@task)
    @task.save!
    session[:task_id] = @task.id
  end

  def update
    @task = AdditionTask.find(session[:task_id])
    @task.answer = params[:addition_task][:answer]
    @task.save!
    render action: :new
  end

  private

  def new_task(task)
    @task.first_addend = 1 + Random.rand(98)
    @task.second_addend = 1 + Random.rand(98)
    @task.sum = @task.first_addend + @task.second_addend
    @task
  end
end