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PORails 3.2: Trying to pass User field through nested form
 

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  1. PORails 3.2: Trying to pass User field through nested form
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    <p>So based on Ryan Bates rails cast (http://railscasts.com/episodes/196-nested-model-form-revised) I am creating a nested form. The part of the rails application that I am trying to get to work ideally does the following:</p> <ul> <li>Let a current user ask a question</li> <li>Then provide an answer for that question afterwards</li> </ul> <p>I managed to get everything working, except that when I try to submit the form once everything is filled out, I keep getting the following error: </p> <pre><code>undefined method `meter_id' for nil:NilClass app/models/answer.rb:13:in `associate_with_meter_id' app/controllers/questions_controller.rb:13:in `create' </code></pre> <p>I believe I know what is wrong, but I am not sure how to fix it. The meter_id is returning an undefined value, because it is not being passed the correct value. Here is the method that associates the meter_id (of answers) with the meter_id (of users):</p> <pre><code>def associate_with_meter_id self.meter_id = user.meter_id end </code></pre> <p><strong>Here is a partial of my user model</strong> </p> <pre><code>class User &lt; ActiveRecord::Base # Include default devise modules. Others available are: # :token_authenticatable, :encryptable, :confirmable, :lockable, :timeoutable and :omniauthable devise :database_authenticatable, :registerable, :recoverable, :rememberable, :trackable, :validatable # Setup accessible (or protected) attributes for your model attr_accessible :email, :password, :password_confirmation, :remember_me, :home_size_sf, :meter_id, :avg_monthly_kwh, :discovery_score, :questions_attributes, :answers_attributes has_many :data_records, :foreign_key =&gt; :meter_id, :primary_key =&gt; :meter_id, :class_name =&gt; "DataRecord" has_many :questions has_many :answers accepts_nested_attributes_for :questions, :answers </code></pre> <p><strong>Here is the questions model</strong></p> <pre><code>class Question &lt; ActiveRecord::Base attr_accessible :description, :taxonomy, :user_id, :answers_attributes belongs_to :user has_many :answers accepts_nested_attributes_for :answers validates :description, presence: { :on =&gt; :create } validates :taxonomy, presence: { :on =&gt; :create } def relevance_score rand end end </code></pre> <p><strong>Here is the questions controller</strong></p> <pre><code>class QuestionsController &lt; ApplicationController respond_to :html, :json def index @question = current_user.questions.new @questions = current_user.questions.all end def create @question = current_user.questions.new(params[:question]) if !params[:update_button] if @question.valid? if params[:next_button] || !@question.save render 'index' elsif !params[:next_button] &amp;&amp; params[:submit_button] &amp;&amp; @question.save flash[:success] = "Your question and answer have been saved." respond_with @question, :location =&gt; questions_path end else render 'index' end else render 'index' end end def next @question = current_user.unanswered.first @answer = Answer.new(:question =&gt; @question, :user =&gt; current_user) respond_to do |format| format.js end end end </code></pre> <p><strong>answers model</strong></p> <pre><code>class Answer &lt; ActiveRecord::Base attr_accessible :value, :user_id, :meter_id, :question_id belongs_to :user belongs_to :question validates :value, presence: true, :numericality =&gt; true before_save :associate_with_meter_id def associate_with_meter_id self.meter_id = user.meter_id **(&lt;-- line 13 from the error message)** end end </code></pre> <p><strong>answers controller</strong></p> <pre><code>class AnswersController &lt; ApplicationController respond_to :html, :json def index @answers = current_user.answers end def create @answer = current_user.answers.create(params[:answer]) if @answer.save flash[:notice] = "Thanks for for answer. Please continue with your input...." respond_with @answer, :location =&gt; root_url end end end </code></pre> <p><strong>database schema</strong></p> <pre><code>ActiveRecord::Schema.define(:version =&gt; 20120210184340) do create_table "answers", :force =&gt; true do |t| t.integer "meter_id" t.integer "user_id" t.integer "question_id" t.float "value" t.float "what_if_value" t.datetime "created_at", :null =&gt; false t.datetime "updated_at", :null =&gt; false end create_table "data_records", :force =&gt; true do |t| t.datetime "timestamp" t.float "value" t.integer "meter_id" t.string "status_code" end create_table "questions", :force =&gt; true do |t| t.string "description" t.string "taxonomy" t.string "coeff" t.float "rsquare", :default =&gt; 0.0 t.string "rank" t.string "responses" t.string "skips" t.string "avganswer" t.float "pval", :default =&gt; 0.0 t.float "quality", :default =&gt; 0.0 t.integer "user_id" t.datetime "created_at", :null =&gt; false t.datetime "updated_at", :null =&gt; false end create_table "setup_constants", :force =&gt; true do |t| t.float "exp_model", :default =&gt; 0.0 t.float "exp_pval_const", :default =&gt; 0.0 end create_table "users", :force =&gt; true do |t| t.integer "meter_id" t.float "home_size_sf", :default =&gt; 1000.0 t.text "notifications" t.float "avg_monthly_kwh" t.float "ee_score" t.string "email", :default =&gt; "", :null =&gt; false t.string "encrypted_password", :default =&gt; "", :null =&gt; false t.string "reset_password_token" t.datetime "reset_password_sent_at" t.datetime "remember_created_at" t.integer "sign_in_count", :default =&gt; 0 t.datetime "current_sign_in_at" t.datetime "last_sign_in_at" t.string "current_sign_in_ip" t.string "last_sign_in_ip" t.datetime "created_at", :null =&gt; false t.datetime "updated_at", :null =&gt; false end add_index "users", ["email"], :name =&gt; "index_users_on_email", :unique =&gt; true add_index "users", ["reset_password_token"], :name =&gt; "index_users_on_reset_password_token", :unique =&gt; true end </code></pre> <p><strong>Note:</strong></p> <p>In the answers model (above), the line:</p> <pre><code>self.meter_id = user.meter_id </code></pre> <p>Associates the meter_id of the answer model with the meter_id of the user model. I believe this is where the issue is. I tried changing the above line to:</p> <pre><code>self.meter_id = 2 </code></pre> <p>And then everything worked fine, so it's obvious that the user.meter_id is undefined, so I'm not sure how to pass that value through the nested form? I tried using a hidden field but with no luck (the following is a nested fields_for :answers, within a form_for @questions):</p> <pre><code>&lt;fieldset&gt; &lt;%= f.label "Yes" %&gt; &lt;%= f.radio_button :value, 1 %&gt; &lt;%= f.label "No" %&gt; &lt;%= f.radio_button :value, 0 %&gt; &lt;%= f.hidden_field :user_id %&gt; &lt;%= f.hidden_field :question_id %&gt; &lt;%= f.hidden_field :meter_id %&gt; &lt;/fieldset&gt; </code></pre>
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    1. USggrillone
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    1. COAre you using the appropriate object in your nested form? For example, if you're using `f` in the parent form, are you using a different object (such as `answer_form`) in the `f.fields_for`? Does your `fields_for` look like: `f.fields_for :answers do |answer_form|`?
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    2. COYes, I'm using the correct object, the fields_for (for the answers) uses 'f' because I put those fields into a partial and passed the 'answer_form' as 'f' to the partial
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      1. PORails 3.2: Trying to pass User field through nested form
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    3. COSo it reads something like this form_for @questions do |f| ..some fields.. f.fields_for :answers do |answer_form| render 'answer_form', f: f end end
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      1. PORails 3.2: Trying to pass User field through nested form
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