Reading value with association (simple_form) - ruby-on-rails

I have such models:
class Grade < ActiveRecord::Base
has_many :question_grades
end
class QuestionGrade < ActiveRecord::Base
belongs_to :grade
belongs_to :question
# it has integer :number
end
class Question < ActiveRecord::Base
# it has string :label
end
I have a simple_form for the 'grade' model, which iterates question_grades:
<%= simple_form_for #grade, :url => "/homeworks/update_grade", :method => :post do |f| %>
<%= f.simple_fields_for :question_grades do |q| %>
<%= q.association :question %>
<%= q.input :number, :collection => 0..2, label: false%>
</div>
</div>
This form creates an editable form for each 'question_grade', where allows visitors to edit 'number' attribute of question_grade. I also want to show a label by using the value, 'question_grade.question.label'. I created an association with 'q.association :question' but it creates an editable input form item. I want to access a value in the association. How can I do that?

When you do
<%= q.association :question %>
you are creating a field to edit this association, as you can see.
What do you need, is to access the q.object, defined as attr_reader here .
in this case, it will be your QuestionGrade instance.
so this:
<%= q.object.question.label %>
may solve your problem.

Related

Rails has_many :through nested forms with simple form

I am trying to make a player character generator. I have a form that hopefully will allow me to attach skills with their values to a character sheet model. I made models like this:
class CharacterSheet < ApplicationRecord
has_many :character_sheet_skills, dependent: :destroy
has_many :skills, through: :character_sheet_skills
belongs_to :user
accepts_nested_attributes_for :skills
end
class Skill < ApplicationRecord
has_many :character_sheet_skills, dependent: :destroy
has_many :character_sheets, through: :character_sheet_skills
attr_reader :value
end
class CharacterSheetSkill < ApplicationRecord
belongs_to :skill
belongs_to :character_sheet
end
Character sheet model holds data about player character and skill model has all skills available in game. In CharacterSheetSkill I'd like to store the skills that the player chooses for his character together with an integer field setting the skill value.
When opening form, I already have a full list of skills in database. All I want to do in form is create a character sheet that has all of these skills with added value. I tried using "fields_for" in form, but I couldn't really get that to work. Right now it looks like this:
<%= simple_form_for [#user, #sheet] do |f| %>
<%= f.input :name %>
<%= f.input :experience, readonly: true, input_html: {'data-target': 'new-character-sheet.exp', class: 'bg-transparent'} %>
...
<%= f.simple_fields_for :skills do |s| %>
<%= s.input :name %>
<%= s.input :value %>
<% end %>
<% end %>
How can I make that form so it saves character sheet together with CharacterSheetSkills?
A better idea here is to use skills as a normalization table where you store the "master" definition of a skill such as the name and the description.
class CharacterSheetSkill < ApplicationRecord
belongs_to :skill
belongs_to :character_sheet
delegate :name, to: :skill
end
You then use fields_for :character_sheet_skills to create rows on the join table explicitly:
<%= f.fields_for :character_sheet_skills do |cs| %>
<fieldset>
<legend><%= cs.name %></legend>
<div class="field">
<%= cs.label :value %>
<%= cs.number_field :value %>
</div>
<%= cs.hidden_field :skill_id %>
</fieldset>
<% end %>
Instead of a hidden fields you could use a select if you want let the user select the skills.
Of course nothing will show up unless you "seed" the inputs:
class CharacterSheetController < ApplicationController
def new
#character_sheet = CharacterSheet.new do |cs|
# this seeds the association so that the fields appear
Skill.all.each do |skill|
cs.character_sheet_skills.new(skill: skill)
end
end
end
def create
#character_sheet = CharacterSheet.new(character_sheet_params)
if #character_sheet.save
redirect_to #character_sheet
else
render :new
end
end
private
def character_sheet_params
params.require(:character_sheet)
.permit(
:foo, :bar, :baz,
character_sheet_skill_attributes: [:skill_id, :value]
)
end
end

ActiveRecord::AssociationTypeMismatch in RoastsController#create

This is a new error to me, and struggling to resolve it. It also states: Roaster(#70130698993440) expected, got "1" which is an instance of String(#70130675908140)
It's highlighting my create method in my Roasts Controller:
def create
#roast = Roast.new(roast_params)
The scenario is that I'm trying to create a triple nested form. for three models Roasts Countries and Regions where roasts has many countries and countries has many regions.
I'm assuming there is something wrong with the roast params, but I can see what it is. I have added the associations there for the nested models
def roast_params
params.require(:roast).permit(:roaster, :name, :bestfor, :beans, :roast, :tastingnotes, :notes, :slug, :avatar, :countries_attributes => [:country_name, :regions_attributes => [:region_name]])
end
my form
<div class="form-group">
<%= form.fields_for :countries do |countries_form| %>
<%= countries_form.label :country %>
<%= countries_form.text_field :name, class: "form-control" %>
</div>
<div class="form-group">
<%= form.fields_for :regions do |regions_form| %>
<%= regions_form.label :region %>
<%= regions_form.text_field :region_name, class: "form-control" %>
<% end %>
<% end %>
</div>
Roast Controller
...
def new
#roast = Roast.new
#roast.countries.build.regions.build
end
...
roast model
class Roast < ApplicationRecord
has_many :tastings
has_many :countries
has_many :notes, through: :tastings
has_many :comments, as: :commentable
belongs_to :roaster
accepts_nested_attributes_for :countries
country model
class Country < ApplicationRecord
has_many :regions, inverse_of: :country
accepts_nested_attributes_for :regions
belongs_to :roasts
region model
class Region < ApplicationRecord
belongs_to :country
I've nested the regions params in the country params, is that correct? I also saw on SO other issues with suggestions for setting config.cache_classes to true in development.rb but that didn't help here.
Update
So looking at this further, I believe it's not related to the nested forms, but rather a collection_select I'm using.
<%= form.label :roaster, class: 'control-label' %>
<%= form.collection_select(:roaster, Roaster.order(:roaster_name).all, :id, :roaster_name, prompt: true, class: "form-control") %>
So this select is pulling the roaster_name from a model called Roaster.
My params now look like the below:
params.require(:roast).permit(:roaster_name, :roaster, :name, :bestfor, :beans, :roast, :tastingnotes, :notes, :slug, :avatar, :countries_attributes => [:country_id, :country_name, :regions_attributes => [:region_id, :region_name]])
And looking at the console when submitting the form, it seems that just the :id of Roaster is getting passed, rather than the value of :roaster_name.
{"utf8"=>"✓",
"authenticity_token"=>"EG+zty85IiVsgipm1pjSAEZ7M66ELWefLq8Znux+cf89sSnVXxielRr1IaSS9+cJvdQD8g1D4+v2KqtKEwh6gw==",
"roast"=>{"roaster"=>"1", "name"=>"Espress", "countries_attributes"=>{"0"=>{"country_name"=>"UK"}}, "regions"=>{"region_name"=>"Highlands"}, "bestfor"=>"", "roast"=>"", "tastingnotes"=>""},
"commit"=>"Create Roast"}
Can't work this out
ActiveRecord::AssociationTypeMismatch is raised when an association-setter (Roast#roaster= in this case) is called with a value that is not an instance of the expected class. Roaster was expected, got String.
The issue seems to be with passing roaster in as a param, which is "1" (String) in your example. I'm guessing this is actually an ID of a Roaster, the form code in the question does not show it.
Perhaps you meant to permit and pass a roaster_id param?
def roast_params
params.require(:roast).permit(:roaster_id, # ...
end

How do I reference an existing instance of a model in a nested Rails form?

I'm attempting to build a recipe-keeper app with three primary models:
Recipe - The recipe for a particular dish
Ingredient - A list of ingredients, validated on uniqueness
Quantity - A join table between Ingredient and Recipe that also reflects the amount of a particular ingredient required for a particular recipe.
I'm using a nested form (see below) that I constructed using an awesome Railscast on Nested Forms (Part 1, Part 2) for inspiration. (My form is in some ways more complex than the tutorial due to the needs of this particular schema, but I was able to make it work in a similar fashion.)
However, when my form is submitted, any and all ingredients listed are created anew—and if the ingredient already exists in the DB, it fails the uniqueness validation and prevents the recipe from being created. Total drag.
So my question is: Is there a way to submit this form so that if an ingredient exists whose name matches one of my ingredient-name fields, it references the existing ingredient instead of attempting to create a new one with the same name?
Code specifics below...
In Recipe.rb:
class Recipe < ActiveRecord::Base
attr_accessible :name, :description, :directions, :quantities_attributes,
:ingredient_attributes
has_many :quantities, dependent: :destroy
has_many :ingredients, through: :quantities
accepts_nested_attributes_for :quantities, allow_destroy: true
In Quantity.rb:
class Quantity < ActiveRecord::Base
attr_accessible :recipe_id, :ingredient_id, :amount, :ingredient_attributes
belongs_to :recipe
belongs_to :ingredient
accepts_nested_attributes_for :ingredient
And in Ingredient.rb:
class Ingredient < ActiveRecord::Base
attr_accessible :name
validates :name, :uniqueness => { :case_sensitive => false }
has_many :quantities
has_many :recipes, through: :quantities
Here's my nested form that displays at Recipe#new:
<%= form_for #recipe do |f| %>
<%= render 'recipe_form_errors' %>
<%= f.label :name %><br>
<%= f.text_field :name %><br>
<h3>Ingredients</h3>
<div id='ingredients'>
<%= f.fields_for :quantities do |ff| %>
<div class='ingredient_fields'>
<%= ff.fields_for :ingredient_attributes do |fff| %>
<%= fff.label :name %>
<%= fff.text_field :name %>
<% end %>
<%= ff.label :amount %>
<%= ff.text_field :amount, size: "10" %>
<%= ff.hidden_field :_destroy %>
<%= link_to_function "remove", "remove_fields(this)" %><br>
</div>
<% end %>
<%= link_to 'Add ingredient', "new_ingredient_button", id: 'new_ingredient' %>
</div><br>
<%= f.label :description %><br>
<%= f.text_area :description, rows: 4, columns: 100 %><br>
<%= f.label :directions %><br>
<%= f.text_area :directions, rows: 4, columns: 100 %><br>
<%= f.submit %>
<% end %>
The link_to and link_to_function are there to allow the addition and removal of quantity/ingredient pairs on the fly, and were adapted from the Railscast mentioned earlier. They could use some refactoring, but work more or less as they should.
Update: Per Leger's request, here's the relevant code from recipes_controller.rb. In the Recipes#new route, 3.times { #recipe.quantities.build } sets up three blank quantity/ingredient pairs for any given recipe; these can be removed or added to on the fly using the "Add ingredient" and "remove" links mentioned above.
class RecipesController < ApplicationController
def new
#recipe = Recipe.new
3.times { #recipe.quantities.build }
#quantity = Quantity.new
end
def create
#recipe = Recipe.new(params[:recipe])
if #recipe.save
redirect_to #recipe
else
render :action => 'new'
end
end
You shouldn't put the logic of ingredients match into view - it's duty of Recipe#create to create proper objects before passing 'em to Model. Pls share the relevant code for controller
Few notes before coming to code:
I use Rails4#ruby2.0, but tried to write Rails3-compatible code.
attr_acessible was deprecated in Rails 4, so strong parameters are used instead. If you ever think to upgrade your app, just go with strong parameters from the beginning.
Recommend to make Ingredient low-cased to provide uniform appearance on top of case-insensitivity
OK, here we go:
Remove attr_accessible string in Recipe.rb, Quantity.rb and Ingredient.rb.
Case-insensitive, low-cased Ingredient.rb:
class Ingredient < ActiveRecord::Base
before_save { self.name.downcase! } # to simplify search and unified view
validates :name, :uniqueness => { :case_sensitive => false }
has_many :quantities
has_many :recipes, through: :quantities
end
<div id='ingredients'> part of adjusted form to create/update Recipe:
<%= f.fields_for :quantities do |ff| %>
<div class='ingredient_fields'>
<%= ff.fields_for :ingredient do |fff| %>
<%= fff.label :name %>
<%= fff.text_field :name, size: "10" %>
<% end %>
...
</div>
<% end %>
<%= link_to 'Add ingredient', "new_ingredient_button", id: 'new_ingredient' %>
We should use :ingredient from Quantity nested_attributes and Rails will add up _attributes-part while creating params-hash for further mass assignment. It allows to use same form in both new and update actions. For this part works properly association should be defined in advance. See adjusted Recipe#new bellow.
and finally recipes_controller.rb:
def new
#recipe = Recipe.new
3.times do
#recipe.quantities.build #initialize recipe -> quantities association
#recipe.quantities.last.build_ingredient #initialize quantities -> ingredient association
end
end
def create
#recipe = Recipe.new(recipe_params)
prepare_recipe
if #recipe.save ... #now all saved in proper way
end
def update
#recipe = Recipe.find(params[:id])
#recipe.attributes = recipe_params
prepare_recipe
if #recipe.save ... #now all saved in proper way
end
private
def prepare_recipe
#recipe.quantities.each do |quantity|
# do case-insensitive search via 'where' and building SQL-request
if ingredient = Ingredient.where('LOWER(name) = ?', quantity.ingredient.name.downcase).first
quantity.ingredient_id = quantity.ingredient.id = ingredient.id
end
end
end
def recipe_params
params.require(:recipe).permit(
:name,
:description,
:directions,
:quantities_attributes => [
:id,
:amount,
:_destroy,
:ingredient_attributes => [
#:id commented bc we pick 'id' for existing ingredients manually and for new we create it
:name
]])
end
In prepare_recipe we do the following things:
Find ID of ingredient with given name
Set foreign_key quantity.ingredient_id to ID
Set quantity.ingredient.id to ID (think what happens if you don't do that and change ingredient name in Recipe)
Enjoy!

Fields_for setting up form not working correcty with accepts_nested_attributes

I'm sure that this is just a lack of experience on my part so bear with me.
I have a model MenuItem that has a Price. Different item types (menu_items, products, events) can have prices.
I have set it up as follows:
class MenuItem < ActiveRecord::Base
...
has_one :price, :as => :pricable
accepts_nested_attributes_for :price
attr_accessible :price_attributes
...
end
class Price < ActiveRecord::Base
belongs_to :pricable, :polymorphic => true
end
The Price object has a price value which is a decimal(8,2) on Mysql5.
In my form:
<%= form_tag "/menus/save" do %>
...
<% menu_header_form.menu_items.each do |item| %>
<div><%=item['header'] %></div>
<%=text_field :menu_item, :header, :index=>item.id, :value=>item.header %>
<%=text_field :menu_item, :sort, :index=>item.id, :value=>item.sort, :size => 2 %>
<% item.fields_for :price do |menu_item_price| %>
<%= menu_item_price.text_field :price %>
<% end %>
<% end %>
and am getting the following error:
undefined method `fields_for' for #<MenuItem:0x007fec8d9be138>
How would I iterate through to get the price value? Would the way that my models are set up mean that those menu_items would have a price record associated with them by default(even empty / null values)?
thx
you need fields_for :price , not item.fields_for
for a more complete example, take a look at the pattern here
All menu items would have a null value for price unless you explicitly give them one which you could do in a before_save callback if you chose

Rails updating multiple models on a single form

Im writing a form which uses formtastic to manage the BusinessUnit model, however when creating a new BusinessUnit it also has to create a number of other record types. The associations between the models are as below:
class BusinessUnit < ActiveRecord::Base
has_many :business_unit_sites
has_many :locations
class BusinessUnitSite < ActiveRecord::Base
belongs_to :site
belongs_to :business_unit
class Site < ActiveRecord::Base
has_many :locations
has_many :business_unit_sites
class Location < ActiveRecord::Base
belongs_to :business_unit
belongs_to :site
When a BusinessUnit is created, a Site must also be created using BusinessUnitSite as a join table. In addition a Location record should be created which must hold a foreign key to the new Site record and this is where Im having problems.
I can create a new Location using a nested form (below) but the Site will have to be created manually.
<%= semantic_form_for #business_unit do |f| %>
<%= f.inputs do %>
<%= f.input :name %>
<%= f.input :business_unit_id %>
<%= f.input :business_unit_group, :include_blank => false %>
<%= f.input :business_unit_type %>
<%= f.input :tax_region, :include_blank => false %>
<%= f.semantic_fields_for :locations do |l| %>
<%= l.input :name, :label => "Location Name" %>
<% end %>
<% end %>
<%= f.buttons %>
<% end %>
What is the best way to create the Location, Site records and ensure that Location holds the foreign key of the newly created Site?
You probably want to do something like using the "fields_for" approach for the sub-objects in your form.
See this related answer:
Multiple objects in a Rails form
More info about fields_for:
http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html
http://apidock.com/rails/ActionView/Helpers/FormHelper/fields_for

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