I've setup a nested form in my rails 3.2.3 app, it's working fine, my models are:
class Recipe < ActiveRecord::Base
attr_accessible :title, :description, :excerpt, :date, :ingredient_lines_attributes
has_and_belongs_to_many :ingredient_lines
accepts_nested_attributes_for :ingredient_lines
end
and:
class IngredientLine < ActiveRecord::Base
attr_accessible :ingredient_id, :measurement_unit_id, :quantity
has_and_belongs_to_many :recipes
belongs_to :measurement_unit
belongs_to :ingredient
end
As above, a Recipe can have multiple IngredientLines and vice versa.
What I'm trying to avoid is record duplication on IngredienLine table.
For example imagine that for recipe_1 an IngredientLine with {"measurement_unit_id" => 1, "ingredient_id" => 1, "quantity" => 3.5} is associated, if for recipe_5 the IngredientLine child form is compiled by the user with the same values, I don't want a new record on IngredientLine table, but only a new association record in the join table ingredient_lines_recipes.
Note that currently I dont't have any IngredientLine controller as saving and updating IngredientLines is handled by nested form routines. Even my Recipe controller is plain and standard:
class RecipesController < ApplicationController
respond_to :html
def new
#recipe = Recipe.new
end
def create
#recipe = Recipe.new(params[:recipe])
flash[:notice] = 'Recipe saved.' if #recipe.save
respond_with(#recipe)
end
def destroy
#recipe = Recipe.find(params[:id])
#recipe.destroy
respond_with(:recipes)
end
def edit
respond_with(#recipe = Recipe.find(params[:id]))
end
def update
#recipe = Recipe.find(params[:id])
flash[:notice] = 'Recipe updated.' if #recipe.update_attributes(params[:recipe])
respond_with(#recipe)
end
end
My guess is that should be enough to override the standard create behavior for IngredientLine with find_or_create, but I don't know how to achieve it.
But there's another important point to take care, imagine the edit of a child form where some IngredientLines are present, if I add another IngredientLine, which is already stored in IngredientLine table, rails of course should not write anything on IngredientLine table, but should also distinguish between child records already associated to the parent, and the new child record for which needs to create the relation, writing a new record on the join table.
Thanks!
in Recipe model redefine method
def ingredient_lines_attributes=(attributes)
self.ingredient_lines << IngredientLine.where(attributes).first_or_initialize
end
Old question but I had the same problem. Forgot to add :id to white list with rails 4 strong_parameters.
For example:
widgets_controller.rb
def widget_params
params.require(:widget).permit(:name, :foos_attributes => [:id, :name, :_destroy],)
end
widget.rb
class Widget < ActiveRecord::Base
has_many :foos, dependent: :destroy
accepts_nested_attributes_for :foos, allow_destroy: true
end
foo.rb
class Foo < ActiveRecord::Base
belongs_to :widget
end
I have run into a similar situation and found inspiration in this answer. In short, I don't worry about the duplication of nested models until save time.
Translated to your example, I added autosave_associated_records_for_ingredient_lines to Recipe. It iterates through ingredient_lines and performs a find_or_create as your intuition said. If ingredient_lines are complex, Yuri's first_or_initialize approach may be cleaner.
I believe this has the behavior you're looking for: nested models are never duplicated, but editing one causes a new record rather than updating a shared one. There is the strong possibility of orphaned ingredient_lines but if that's a serious concern you could choose to update if that model has only one recipe with an id that matches the current one.
Related
I have a table that has set entries. I would like to access those entries as variables in both my models and controllers without querying the database every time to set those variables.
I am able to get it to work by creating duplicate "concerns" for my models and controllers. I could also set global variables in my ApplicationController. Or i could initialize them in every place that I need them. What would be the correct rails way to set and access global variables that can be accessed in both controllers and models?
class ItemType
has_many :items
end
class Item
belongs_to :item_type
belongs_to :foo
end
class Foo
has_many :items
def build_item
bar_item_type = ItemType.find_by(:name => "bar")
self.items.build(
:foo_id => self.id,
:item_type_id => bar_item_type.id
)
end
end
class ItemsController
def update
bar_item_type = ItemType.find_by(:name => "bar")
#item.update(:item_type_id => bar_item_type.id)
end
end
In the example, you can see that I am declaring the bar_item_type variable in both my Foo model and my ItemsController. I would like to DRY up my code base by being able to create and access that variable once for my rails project instead of having to make that same database call everywhere.
I would advocate against such hard-coded or DB state-dependent code. If you must do it, here's how one of the ways I know it can be done:
# models
class ItemType < ActiveRecord::Base
has_many :items
# caches the value after first call
def self.with_bar
##with_bar ||= transaction { find_or_create_by(name: "bar") }
end
def self.with_bar_id
with_bar.id
end
end
class Item < ActiveRecord::Base
belongs_to :item_type
belongs_to :foo
scope :with_bar_types, -> { where(item_type_id: ItemType.with_bar_id) }
end
class Foo < ActiveRecord::Base
has_many :items
# automatically sets the foo_id, no need to mention explicitly
# the chained with_bar_types automatically sets the item_type_id to ItemType.with_bar_id
def build_item
self.items.with_bar_types.new
end
end
# Controller
class ItemsController
def update
#item.update(item_type_id: ItemType.with_bar_id)
end
end
If you MUST use a constant, there are a few ways to do it. But you must take into account that you are instantiating an ActiveRecord model object which is dependent on data being present in the database. This is not recommend, because you now have model and controller logic relying on data being present in the database. This might be ok if you have seeded your database and that it won't change.
class ItemType
BAR_TYPE ||= where(:name => "bar").limit(1).first
has_many :items
end
Now where ever you need this object you can call it like this:
bar_item_type = ItemType::BAR_TYPE
Using: Rails 4.1.4, PostgreSQL 9.1.13
Hi. I'm have a simple problem, but for some reason I can't get it done. The picture is this:
Models
class Article < ActiveRecord::Base
belongs_to :user
has_many :votes
end
class User < ActiveRecord::Base
has_many :articles
has_many :votes
end
class Vote < ActiveRecord::Base
belongs_to :article
belongs_to :user, scope: :hotel_id
validates_inclusion_of :value, in: 0..5
validates_uniqueness_of :user_id, :article_id
end
Idea
Each User can Vote for each Article but only once (to avoid multiple voting).
Vote model has a 'value' attribute that is the range 0..10.
ArticlesController except standard CRUD methods has action #showcase which must return 5 articles with the top votes rating from the DB and sort them in the descending order (and render the respective view).
So I understand that the proper way is to write the class method in the Article Model (smth. like "by_top_votes") and use it in the ArticlesController#showcase:
def showcase
#top_five_articles = Article.by_top_votes
end
The problem is that I can't write the proper query to the DB which will: 1)find articles, 2)find all votes of the each article, 3) sum all values of the respective article's votes, 4)sort them (this step I know how to do).
Thank you for reading and for the help.
P.S. Maybe my way to solve problem is almost wrong. If this so, please tell my the right one.
Ok, I've done it by myself. If anybody will stuck with the same problem, here is solution for it.
1. In Vote model summarize the vote's values:
def self.sum_value
sum(:value)
end
2. Add new attribute (and column) to Article - user_rating:integer.
3. In the Article model define two class methods:
# assign user_rating attribute with the sum of all votes values
def set_user_rating
user_rating = self.votes.sum_value
self.update_attribute(:user_rating, user_rating)
end
# get top 5 articles by user_rating value from db
def self.top_by_user_rating
Article.order(:user_rating).reverse_order.limit(5)
end
4. In the ArticlesController define showcase action:
def showcase
#top_articles = Article.top_by_user_rating
end
5. In the VotesController define create action:
def create
#article = Article.find(params[:article_id])
#vote = #article.votes.create(vote_params)
if #vote.save
#article.set_user_rating
redirect_to #article, notice: "Thanks for your vote"
else
.
end
end
It works and tests are passing.
Models:
A User has_one Ucellar
A Ucellar belongs_to User
I have confirmed from multiple sources that these are set up correctly. For posterity, here is the top portion of those two models.
class User < ActiveRecord::Base
has_many :authorizations
has_one :ucellar
validates :name, :email, :presence => true
This is actually the entire Ucellar model.
class Ucellar < ActiveRecord::Base
belongs_to :user
end
Ucellar has a column called user_id, which I know is necessary. The part of my application that creates a user uses the method create_with_oath. Below is the entire User class. Note the second line of the create method.
class User < ActiveRecord::Base
has_many :authorizations
has_one :ucellar
validates :name, :email, :presence => true
def create
#user = User.new(user_params)
#ucellar = #user.create_ucellar
end
def add_provider(auth_hash)
# Check if the provider already exists, so we don't add it twice unless authorizations.find_by_provider_and_uid(auth_hash["provider"], auth_hash["uid"])
Authorization.create :user => self, :provider => auth_hash["provider"], :uid => auth_hash["uid"]
end
end
def self.create_with_omniauth(auth)
user = User.create({:name => auth["info"]["name"], :email => auth["info"]["email"]})
end
private
def user_params
params.require(:user).permit(:name, :email)
end
end
EDIT:
Forgot to summarize the symptoms. On create, the user is in the db, with no exceptions thrown, and nothing to signify that anything went wrong. However, the related ucellar is never created. Per the documentation Here, the create method should create AND save the related ucellar.
It should create ucellar too.
Try to get the error messages after the creation by calling:
raise #user.errors.full_messages.to_sentence.inspect
I'm not sure why this wasn't working, but I ended up just moving this code out of the create action of the user controller, and putting it directly after an action that was creating a user. It solved my issue though. Thanks everyone for your help!
I have a many-to-many relationship with a join table in my Rails application. I'm using the has_many :through idiom in my models. To keep things simple, lets call my first class Student, my second class Course, and the join table class Enrollment (which contains fields student_id and course_id). I want to make sure that a given Student is associated with a given Course at most once (i.e. the {student_id, course_id} tuple should be unique in the enrollment table).
So I have a migration a that enforces this uniqueness.
def change
add_index :enrollments, [:student_id, :course_id], :unique => true
end
In addition my model classes are defined as such:
class Student < ActiveRecord::Base
has_many :enrollments
has_many :courses, :through => :enrollment
end
class Course < ActiveRecord::Base
has_many :enrollments
has_many :students, :through => :enrollment
end
class Enrollment < ActiveRecord::Base
belongs_to :student
belongs_to :course
validates :student, :presence => true
validates :course, :presence => true
validates :student_id, :uniqueness => {:scope => :course_id}
end
In a rails console, I can do the following:
student = Student.first
course = Course.first
student.courses << course
#... succeeds
student.courses << course
#... appropriately fails and raises an ActiveRecord::RecordInvalid exception
In my RSpec test, I do the exact same thing and I get no exception with the following code:
#student.courses << #course
expect { #student.courses << #course }.to raise_error(ActiveRecord::RecordInvalid)
And so my test fails and reports:
expected ActiveRecord::RecordInvalid but nothing was raised
What's going on here? What could I be doing wrong? How do I fix it?
Rails uses model level validation, if you want strict checking for uniquiness you need to use database level - foreign keys for example. But in this case you need to catch exceptions from database connector.
This is strange because in my code (very similar to your) validation for unique raises exception.
There's a couple of things here that could be happening:
#courses has changed between uses.
#student has changed between uses.
By using let you'll protect these values from changing between expectations.
let(:course) { Course.first }
let(:student) { Student.first }
subject{ student.courses << course << course }
it { should raise_error(ActiveRecord::RecordInvalid) }
Or, there could just be something wrong with your code :)
Consider the following parent/child relationship where Parent is 1..n with Kids (only the relevant stuff here)...
class Parent < ActiveRecord::Base
# !EDIT! - was missing this require originally -- was the root cause!
require "Kid"
has_many :kids, :dependent => :destroy, :validate => true
accepts_nested_attributes_for :kids
validates_associated :kids
end
class Kid < ActiveRecord::Base
belongs_to :parent
# for simplicity, assume a single field: #item
validates_presence_of :item, :message => "is expected"
end
The validates_presence_of methods on the Kid model works as expected on validation failure, generating a final string of Item is expected per the custom message attribute supplied.
But if try validates_with, instead...
class Kid < ActiveRecord::Base
belongs_to :parent
validates_with TrivialValidator
end
class TrivialValidator
def validate
if record.item != "good"
record.errors[:base] << "Bad item!"
end
end
end
...Rails returns a NameError - uninitialized constant Parent::Kid error following not only an attempt to create (initial persist) user data, but also when even attempting to build the initial form. Relevant bits from the controller:
def new
#parent = Parent.new
#parent.kids.new # NameError, validates_* methods called within
end
def create
#parent = Parent.new(params[:parent])
#parent.save # NameError, validates_* methods called within
end
The error suggests that somewhere during model name (and perhaps field name?) resolution for error message construction, something has run afoul. But why would it happen for some validates_* methods and not others?
Anybody else hit a wall with this? Is there some ceremony needed here that I've left out in order to make this work, particularly regarding model names?
After a few hours away, and returning fresh -- Was missing require "Kid" in Parent class. Will edit.