models/user.rb
class User < ActiveRecord::Base
has_many :clubs, :dependent => :destroy
has_many :announcements, :dependent => :destroy
end
models/announcement.rb
class Announcement < ActiveRecord::Base
belongs_to :user
belongs_to :club
end
models/club.rb
class Club < ActiveRecord::Base
belongs_to :user
has_many :announcements, :dependent => :destroy
end
controllers/announcements/announcements_controller.rb
def index
#announcements = Announcement.find(:all, :include => [:user, :club])
end
Problem:
When i type this code,
views/announcements/index.html.erb
<% #announcements.each do |announcement| %>
<%= announcement.user.username %>
<% end %>
I get this error:
NoMethodError in Announcements#index
undefined method `username' for nil:NilClass
when i change code to this, it works.
<% #announcements.each do |announcement| %>
<%= announcement.club.user.username %>
<% end %>
Why is the first code is not working? What is the difference between these codes. Thanks.
It looks like you've got an announcement which has no user set, but does have a club which in turn does have a user. Perhaps consider adding a validation to require that the :user_id column on announcement is present.
Related
I have three models, ingredient, recipe_ingredient and recipy
class Ingredient < ApplicationRecord
has_many :recipe_ingredients
end
class RecipeIngredient < ApplicationRecord
belongs_to :recipy, :dependent => :destroy
belongs_to :ingredient
end
class Recipy < ApplicationRecord
has_many :recipy_steps
has_many :recipe_ingredients, :dependent => :delete_all
end
I am trying to access the ing_name attribute in the ingredients table from recipies show page.
<% #recipe_ingredients.each do |ing| %>
<p> <%= ing.amount %> <%= ing.unit %>
<%= ing.ingredient.ing_name %>
</p>
def Show from the recipies controller:
def show
#recipe_ingredients = #recipy.recipe_ingredients
end
But I keep receiving the following error msg:
undefined method `ing_name' for nil:NilClass
My ingredient_params:
def ingredient_params
params.require(:ingredient).permit(:ing_name)
end
It does seem to work like this:
<%= Ingredient.where(id: ing.ingredient_id).pluck(:ing_name) %>
But this does not use the connection between the tables if I understand correctly? Any help? Thanks.
You have ingredient nil thats why you got the error.
Must be your controller has some before_action hook to load recipy
class RecipesController < ApplicationController
before_action :load_recipy, only: :show
def show
#recipe_ingredients = #recipy.recipe_ingredients
end
private
def load_recipy
#recipy = Recipy.find(params[:id])
end
end
You can try this to avoid this nil error(undefined method 'ing_name' for nil:NilClass)
<% #recipe_ingredients.each do |ing| %>
<p> <%= ing.amount %> <%= ing.unit %>
<%= ing.try(:ingredient).try(:ing_name) %>
</p>
From Rails 5 by default you got one required option to make ingredient always not nullable
like below
belongs_to :ingredient, required: true
It will also prevent this error of
class RecipeIngredient < ApplicationRecord
belongs_to :recipy, :dependent => :destroy
belongs_to :ingredient, required: true
end
the problem is because inside your show method #recipy is nil,
here is usually code for show
controller
def show
#recipy = Recipy.find(params[:id]) # --> you missed this line
#recipe_ingredients = #recipy.recipe_ingredients # #recipy will be null without line above
end
view
<% #recipe_ingredients.each do |ing| %>
<p> <%= ing.amount %> <%= ing.unit %> <%= ing.ingredient.ing_name %> </p>
<% end %>
I would like also add some suggestion to your model relationship as follow since Ingredient and Recipy shows many to many relationship
class Ingredient < ApplicationRecord
# -> recipe_ingredients -> recipies
has_many :recipe_ingredients, :dependent => :destroy
has_many :recipies, through: :recipe_ingredients
end
class RecipeIngredient < ApplicationRecord
belongs_to :recipy
belongs_to :ingredient
end
class Recipy < ApplicationRecord
has_many :recipy_steps
# -> recipe_ingredients -> ingredients
has_many :recipe_ingredients, :dependent => :destroy
has_many :ingredients, through: :recipe_ingredients
end
I'm having some trouble to implement a nested form with a has_one :through association.
Models
# model: member.rb
belongs_to :user
has_one :academic
# model: user.rb
has_one :member
has_one :academic, through: :member
accepts_nested_attributes_for :member, reject_if: :all_blank
accepts_nested_attributes_for :academic, reject_if: :all_blank
# model: academic.rb
belongs_to :member
belongs_to :user
Controller
# users_controller.rb
def new
#user = User.new
#user.build_member
#user.build_academic
end
I also have tried with:
#user.member.build_academic
View
# new.html.erb
<%= simple_form_for(resource, as: resource_name, url: registration_path(resource_name)) do |ff| %>
<%= ff.text_field :email %>
# member belongs to user so I can call a fields_for
<% ff.fields_for :member do |f| %>
<%= f.text_field :name %>
# this part is not shown. What is wrong with my association?
<% f.fields_for :academic do |a| %>
<%= a.text_field :major %>
<% end %>
<% end %>
<% end %>
I've taken a look into the Rails documentation. The first fields_for is shown in the page (:member), but the second one (:academic), which has the has_one :through association, is not shown in the page.
Any help will be appreciated. Thank you.
Through
If you want to build your data through a relation, you have to pass the associated data as it's constructed:
#app/models/member.rb
class Member < ActiveRecord::Base
belongs_to :user
has_one :academic
accepts_nested_attributes_for :academic
end
#app/models/user.rb
class User < ActiveRecord::Base
has_one :member
has_one :academic, through: :member
accepts_nested_attributes_for :member
end
#app/models/academic.rb
class Academic < ActiveRecord::Base
belongs_to :member
belongs_to :user
end
This will allow you to do the following:
#app/controllers/members_controller.rb
class MembersController < ApplicationController
def new
#member = Member.new
#member.build_member.build_academic
end
def create
#member = Member.new member_params
#member.save
end
private
def member_params
params.require(:member).permit(:x, :y, :z, academic_attributes: [:some, :attributes, member_attributes:[...]])
end
end
This would permit the following:
#app/views/users/new.html.erb
<%= form_for #user do |f| %>
<%= f.fields_for :member do |m| %>
<%= f.text_field :name %>
...
<%= m.fields_for :academic do |a| %>
<% a.text_field :name %>
...
<% end %>
<% end %>
<%= f.submit %>
<% end %>
This works to build a new member object, and a new academic object from the user. Although not strictly what you're asking, it looks like it could benefit you in some form.
Associations
If you want to do what you're asking (IE build_member and build_academic exclusively), you'll need to get rid of the has_one :through relationship...
#app/models/user.rb
class User < ActiveRecord::Base
has_many :memberships
has_many :academics, through: :memberships
end
#app/models/membership.rb
class Membership < ActiveRecord::Base
belongs_to :user
belongs_to :academic
end
#app/models/academic.rb
class Academic < ActiveRecord::Base
has_many :memberships
has_many :users, through: :memberships
end
The problem is you're basically trying to build a relationship for a direct association (member) and an indirect relationship (academic).
If you want to build both exclusively, you have to make them have a direct association with your main model. The above should allow you to do the following:
#app/controllers/users_controller.rb
class UsersController < ApplicationController
def new
#user = User.new
#user.members.build.academics.build
end
end
Much like my top example, this will pass nested data through your form - if you wanted to have it completely exclusively, do this:
#app/models/user.rb
class User < ActiveRecord::Base
has_one :member
has_one :academic
has_and_belongs_to_many :academics
end
#app/models/member.rb
class Member < ActiveRecord::Base
belongs_to :user
end
#app/models/academic.rb
class Academic < ActiveRecord::Base
belongs_to :user
has_and_belongs_to_many :users
end
This will allow the following:
#app/controllers/users_controller.rb
class UsersController < ApplicationController
def new
#user = User.new
#user.build_member
#user.build_academic
end
def create
#user = User.new user_params
#user.save
end
private
def user_params
params.require(:user).permit(:user, :params, member_attributes: [], academic_attributes:[])
end
end
For future reference or for anyone that has the same problem, I found a way around to fix this problem, in case you have same structure.
I could fix this by going to the view, before the form, and writing:
<% resource.member.build_academic %>
In my case resource is User, set by devise, a Rails gem used for authentication.
And you don't need to reference any :through or whatsoever in your model.
It is not the most efficient way, but I haven't found any other solution. Hope it helps.
I'm having issue creating a nested polymorphic form. I am following the solution from this problem:
Rails: has_many through with polymorphic association - will this work?
The description was: A Person can have many Events and each Event can have one polymorphic Eventable record
Here are the relevant models:
class Event < ActiveRecord::Base
belongs_to :person
belongs_to :eventable, :polymorphic => true
end
class Meal < ActiveRecord::Base
has_one :event, :as => eventable
end
class Workout < ActiveRecord::Base
has_one :event, :as => eventable
end
class Person < ActiveRecord::Base
has_many :events
has_many :meals, :through => :events, :source => :eventable,
:source_type => "Meal"
has_many :workouts, :through => :events, :source => :eventable,
:source_type => "Workout"
end
My controller looks like this:
def
#person = Person.new
#person.meals.new
#person.workouts.new
new
My view looks like this:
<%= form_for #person do |person| %>
<%= person.fields_for :meals, #person.meals.build do |meals| %>
<%= meals.text_field :food %>
<% end %>
<% end %>
The error I am currently getting is:
unknown attribute: person_id
I would think that the polymorphic association is hindering the creation of the object because meals can't be create until person has been created? Did I set up the form correctly? Thanks!
You'll need to include a person_id attribute in the events table (as per the belongs_to association)
There are also some other issues you should resolve:
Controller
def new
#person = Person.build
end
def create
#person = Person.new(person_attributes)
#person.save
end
private
def person_attributes
params.require(:person).permit(:your, :attributes, events_attributes: [:eventable_type, :eventable_id, meal_attributes: [:params], workout_attributes: [:params]])
end
Models
#app/models/person.rb
Class Person < ActiveRecord::Base
has_many :events
has_many :meals, :through => :events, :source => :eventable,
:source_type => "Meal"
has_many :workouts, :through => :events, :source => :eventable,
:source_type => "Workout"
def self.build
person = Person.new
person.events.build.build_meal
person.events.build.build_workout
end
end
Views
#app/views/people/new.html.erb
<%= form_for #person do |person| %>
<%= person.fields_for :events do |e| %>
<%= e.fields_for :meal %>
<%= e.text_field :food %>
<% end %>
<% end %>
<% end %>
I am working on a project involving three models (recipient, award, announcer) and need to have a nested attributes when issuing an award by an announcer to multiple recipients. For an example, award form need to have the ability to do 3 things:
Can add multiple-recipients (i.e. "add recipient", "remove recipient") - nested attributes
After creating a new award, the award will be posted into recipient's profile.
Enables future polling of #recipient.awards and #announcer.awards
Really struggle in terms of how to smartly solve this problem. The following data structure kind of made sense, however can not do "accepts_nested_attributes_for :recipients" in the award form. Can you help? Many thanks in advance.
class Recipient < ActiveRecord::Base
has_many :awards
has_many :announcers, :through => :awards
end
class Announcer < ActiveRecord::Base
has_many :awards
has_many :recipients, :through => :awards
end
class Award < ActiveRecord::Base
belongs_to :announcer
belongs_to :recipient
end
You're just about there. The main issue is that you're trying to create recipient objects in the form rather than just creating a relationship between the award and another object (user). You could do something like this:
class User < ActiveRecord::Base
has_many :recipients
has_many :awards, :through => :recipients
end
# this is your relationship between an award and a user
class Recipient < ActiveRecord::Base
belongs_to :user
belongs_to :award
end
class Award < ActiveRecord::Base
has_many :recipients
has_many :users, :through => :recipients
belongs_to :announcer
accepts_nested_attributes_for :recipients, :allow_destroy => true
end
class Announcer < ActiveRecord::Base
has_many :awards
has_many :recipients, :through => :awards
end
Then you would just do a nested form that would build the recipients_attributes array:
<%= form_for #award do |f| %>
<%= f.text_field :name %>
<div id="recipients">
<% #award.recipients.each do |recipient| %>
<%= render :partial => '/recipients/new', :locals => {:recipient => recipient, :f => f} %>
<% end %>
</div>
<%= link_to_function 'add recipient', "jQuery('#recipients').append(#{render(:partial => '/recipients/new').to_json})" %>
<% end %>
And, to keep it DRY just push the nested part into a partial:
# app/views/recipients/_new.html.erb
<% recipient ||= Recipient.new %>
<%= f.fields_for 'recipients_attributes[]', recipient do |rf| %>
<%= rf.select :user_id, User.all %>
<%= fr.check_box '_delete' %>
<%= fr.label '_delete', 'remove' %>
<% end %>
Obviously the User.all call isn't ideal so maybe make that an autocomplete.
I have built a ruby on rails app that lets users track their workouts. User has_many workouts. In addition, a User can create a box (gym) if they are a gym owner. Users can then associate with that box through a Membership resource.
I create that association for the current_user with a remote form in /views/boxes/show.html.erb:
<% remote_form_for Membership.new do |f| %>
<%= f.hidden_field :box_id, :value => #box.id %>
<%= f.hidden_field :user_id, :value => current_user.id %>
<%= submit_tag "I am a member of this box" , :class => '' %>
<% end %>
I now want to give the current_user the ability to remove their association. How do I structure the link/form and what should the memberships_controller destroy action look like?
Below is a list of my associations if it helps:
User
class User < ActiveRecord::Base
has_many :boxes
has_many :workouts, :dependent => :destroy
end
Workout
class Workout < ActiveRecord::Base
belongs_to :user
belongs_to :box
end
Box
class Box < ActiveRecord::Base
belongs_to :user
has_many :users, :through => :memberships
has_many :workouts, :through => :users
has_many :memberships
end
Membership
class Membership < ActiveRecord::Base
belongs_to :user
belongs_to :box
end
After you have done the changes suggested here, and assuming that you have obtained the membership for the current_user and the box using the following code,
#membership = current_user.memberships.for_box(box).first
create a link for the user to delete the membership as follows.
link_to 'Delete Membership', membership_path(#membership), :method => :delete
Membership controller should have a destroy method that looks like the following.
def destroy
#membership = Membership.find(params[:id])
#membership.destroy
end
This is assuming that your memberships controller is restful and you have map.resources :memberships in your routes.