I have a rails application that models a house. house contains rooms
and rooms have nested attributes for light and small_appliance. I have
a calculator controller, which is how end users will access the
application.
My problem is that I can’t get the partial for adding rooms to submit
correctly from calculator. The initial page lets the user enter house
information, which is saved using save_house when submit is clicked.
This also redirects the user to the add_rooms page, where they can add
rooms to the house.
add_rooms displays correctly, but when I click submit, I get this
error:
RuntimeError in Calculator#add_room
Showing app/views/calculator/add_rooms.html.erb where line #2 raised:
Called id for nil, which would mistakenly be 4 – if you really wanted
the id of nil, use object_id
Extracted source (around line #2):
1:
2:
House id is <%= @house.id %>
3:
4:
Your rooms:
5: <% if @house.rooms %>
RAILS_ROOT: C:/Users/ryan/Downloads/react
Application Trace | Framework Trace | Full Trace
C:/Users/ryan/Downloads/react/app/views/calculator/add_rooms.html.erb:
2:in _run_erb_app47views47calculator47add_rooms46html46erb' C:/Users/ryan/Downloads/react/app/controllers/calculator_controller.rb: 36:inadd_room’
C:/Users/ryan/Downloads/react/app/controllers/calculator_controller.rb:
33:in `add_room’
This is odd to me, because when add_rooms first renders, it shows the
house_id. I don’t understand why it isn’t passed after the form is
submitted.
Here’s the code:
#app/models/room.rb
class Room < ActiveRecord::Base
schema { name:string, house_id:integer }
belongs_to :house
has_many :lights, :dependent => :destroy
has_many :small_appliances, :dependent => :destroy
validates_presence_of :name
accepts_nested_attributes_for :lights, :reject_if => lambda { |a|
a.values.all?(&:blank?) }, :allow_destroy => true
accepts_nested_attributes_for :small_appliances, :reject_if =>
lambda { |a| a.values.all?(&:blank?) }, :allow_destroy =>
true
end
#app/models/house.rb
class House < ActiveRecord::Base
has_many :rooms
validation code not included
def add_room(room)
rooms << room
end
end
#app/controllers/calculator_controller.rb
class CalculatorController < ApplicationController
def index
end
def save_house
@house = House.new(params[:house])
respond_to do |format|
if @house.save
format.html { render :action => ‘add_rooms’, :id => @house }
format.xml { render :xml => @house, :status
=> :created, :location => @house }
else
format.html { render :action => ‘index’ }
format.xml { render :xml => @house.errors, :status
=> :unprocessable_entity }
end
end
end
def add_rooms
@house = House.find(params[:id])
@rooms = Room.find_by_house_id(@house.id)
rescue ActiveRecord::RecordNotFound
logger.error(“Attempt to access invalid house #{params[:id]}”)
flash[:notice] = “You must create a house before adding rooms”
redirect_to :action => ‘index’
end
def add_room
@room = Room.new(params[:room])
@house = @room.house
respond_to do |format|
if @room.save
flash[:notice] = "Room \"#[email protected]}\" was successfully
added."
format.html { render :action => ‘add_rooms’ }
format.xml { render :xml => @room, :status
=> :created, :location => @room }
else
format.html { render :action => ‘add_rooms’ }
format.xml { render :xml => @room.errors, :status
=> :unprocessable_entity }
end
end
rescue ActiveRecord::RecordNotFound
logger.error(“Attempt to access invalid house #{params[:id]}”)
flash[:notice] = “You must create a house before adding a room”
redirect_to :action => ‘index’
end
def report
flash[:notice] = nil
@house = House.find(params[:id])
@rooms = Room.find_by_house_id(@house.id)
rescue ActiveRecord::RecordNotFound
logger.error(“Attempt to access invalid house #{params[:id]}”)
flash[:notice] = “You must create a house before generating a
report”
redirect_to :action => ‘index’
end
end
#app/views/calculator/add_rooms.html.erb
House id is <%= @house.id %>
Your rooms:
<% if @house.rooms %>-
<% for room in @house.rooms %>
- <%= h room.name %> has <%= h room.number_of_bulbs %> <%= h room.wattage_of_bulbs %> watt bulbs, in use for <%= h room.usage_hours %> hours per day. <% end %>
You have not added any rooms yet
<% end %><%= render :partial => ‘rooms/room_form’ %>
<%= button_to “Continue to report”, :action => “report”, :id => @house
%>
#app/views/rooms/_room_form.html.erb
<% form_for :room, @house.rooms.build, :url => { :action
=> :add_room } do |form| %>
<%= form.error_messages %>
<%= form.label :name %>
<%= form.text_field :name %>
Lights
<% form.object.lights.build if form.object.lights.empty? %> <% form.fields_for :lights do |light_form| %> <%= render :partial => "light", :locals => { :form => light_form } %> <% end %><%= add_child_link "[+] Add new light", form, :lights %>
Small Appliances
<% form.object.small_appliances.build if form.object.small_appliances.empty? %> <% form.fields_for :small_appliances do |sm_appl_form| %> <%= render :partial => "small_appliance", :locals => { :form => sm_appl_form } %> <% end %><%= add_child_link "[+] Add new small appliance", form, :small_appliances %>
<%= form.submit "Submit" %>
<% end %>#application_helper.rb
module ApplicationHelper
def remove_child_link(name, form)
form.hidden_field(:_delete) + link_to_function(name, “remove_fields
(this)”)
end
def add_child_link(name, form, method)
fields = new_child_fields(form, method)
link_to_function(name, h(“insert_fields(this, “#{method}”, “#
{escape_javascript(fields)}”)”))
end
def new_child_fields(form_builder, method, options = {})
options[:object] ||=
form_builder.object.class.reflect_on_association(method).klass.new
options[:partial] ||= method.to_s.singularize
options[:form_builder_local] ||= :form
form_builder.fields_for(method, options[:object], :child_index =>
“new_#{method}”) do |form|
render(:partial => options[:partial], :locals => { options
[:form_builder_local] => form })
end
end
end
Thanks,
Ryan