I'm new to rails. I want to create simple url for the users, I don't want to use friendly_id, if possible. I can already change the url using this
#MyModel.rb
def to_param
address
end
#MyController.rb
#user = Admin::Account.find_by_address(params[:id])
but what I really want is to use name instead of address, but the problem is that, name does not belong to MyModel.rb it balongs to OtherModel.rb, is this even pissible? please help
here is a sample of what I want
#MyModel.rb
def to_param
name #name is a data/column from OtherModel.rb
end
#MyController.rb
#user = Admin::Account.find_by_name(params[:id])
#instead of using find_by_address I can now use find_by_name
here is a sample of my model relations
class Admin::MyModel < ActiveRecord::Base
has_many :other_model, :class_name => 'Admin::OtherModel', dependent: :destroy
end
class Admin::OtherModel < ActiveRecord::Base
belongs_to :my_model, :class_name => 'Admin::MyModel'
end
Related
I'm working with three tables as follows:
article.rb
class Article < ActiveRecord::Base
has_many :comments
has_many :comentarios, :through => :comments
end
comment.rb
class Comment < ActiveRecord::Base
belongs_to :article
has_many :comentarios
end
and comentario.rb
class Comentario < ActiveRecord::Base
belongs_to :article
end
Everything works fine until I attempt to add a 'comentario' and returns this error
ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection in ComentariosController#create
Cannot modify association 'Article#comentarios' because the source reflection class 'Comentario' is associated to 'Comment' via :has_many.
This is the code I use to create a new 'comentario'
comentarios_controller.rb
class ComentariosController < ApplicationController
def new
#comentario = Comentario.new
end
def create
#article = Article.find(params[:article_id])
#comentario = #article.comentarios.create(comentario_params)
redirect_to article_path(#article)
end
private
def comentario_params
params.require(:comentario).permit(:comentador, :comentario)
end
end
The output returns an error in the line where I create #comentario from calling #article but I can't see why since Ruby documentation says that once I associate comentario to article using :through, I can simply call something like #article.comentario.
Any idea of what is causing this error?
or do you have any suggestion on how to achieve this association in any other way?
Ok. The issue is that Rails is confused about which article to use here.
Your Comment model belongs_to :article but also your Commentario belongs_to :article... so if you use #article.commentarios - it's confused as to whether the article refers to the article of the comment or the article of the commentario.
You will probably need to update your form to be more explicit about what you're referring to. A form for the commentario should actually include fields for the comment it creates.
Somebody else had the same problem here. You may wish to look at the solution here: "Cannot modify association because the source reflection class is associated via :has_many"
I have a survey and I would like to add participants to a Participant model whenever a user answers to a question for the first time. The survey is a bit special because it has many functions to answer questions such as Tag words, Multiple choices and Open Question and each function is actually a model that has its own records. Also I only want the Participant to be saved once.
The Participant model is fairly simple:
class Participant < ActiveRecord::Base
belongs_to :survey
attr_accessible :survey_id, :user_id
end
The Survey model is also straightforward:
class Survey < ActiveRecord::Base
...
has_many :participants, :through => :users
has_many :rating_questions, :dependent => :destroy
has_many :open_questions, :dependent => :destroy
has_many :tag_questions, :dependent => :destroy
belongs_to :account
belongs_to :user
accepts_nested_attributes_for :open_questions
accepts_nested_attributes_for :rating_questions
accepts_nested_attributes_for :tag_questions
...
end
Then you have models such as rating_answers that belong to a rating_question, open_answers that belong to open_questions and so on.
So initially I thought for within my model rating_answers I could add after_create callback to add_participant
like this:
class RatingAnswer < ActiveRecord::Base
belongs_to :rating_question
after_create :add_participant
...
protected
def add_participant
#participant = Participant.where(:user_id => current_user.id, :survey_id => Survey.find(params[:survey_id]))
if #participant.nil?
Participant.create!(:user_id => current_user.id, :survey_id => Survey.find(params[:survey_id]))
end
end
end
In this case, I didn't know how to find the survey_id, so I tried using the params but I don't think that is the right way to do it. regardles it returned this error
NameError (undefined local variable or method `current_user' for #<RatingAnswer:0x0000010325ef00>):
app/models/rating_answer.rb:25:in `add_participant'
app/controllers/rating_answers_controller.rb:12:in `create'
Another idea I had was to create instead a module Participants.rb that I could use in each controllers
module Participants
def add_participant
#participant = Participant.where(:user_id => current_user.id, :survey_id => Survey.find(params[:survey_id]))
if #participant.nil?
Participant.create!(:user_id => current_user.id, :survey_id => Survey.find(params[:survey_id]))
end
end
end
and in the controller
class RatingAnswersController < ApplicationController
include Participants
def create
#rating_question = RatingQuestion.find_by_id(params[:rating_question_id])
#rating_answer = RatingAnswer.new(params[:rating_answer])
#survey = Survey.find(params[:survey_id])
if #rating_answer.save
add_participant
respond_to do |format|
format.js
end
end
end
end
And I got a routing error
ActionController::RoutingError (uninitialized constant RatingAnswersController::Participants):
I can understand this error, because I don't have a controller for participants with a create method and its routes resources
I am not sure what is the proper way to add a record to a model from a nested model and what is the cleaner approach.
Ideas are most welcome!
current_user is a helper that's accessible in views/controller alone. You need to pass it as a parameter into the model. Else, it ain't accessible in the models. May be, this should help.
In the end I ended up using the after_create callback but instead of fetching the data from the params, I used the associations. Also if #participant.nil? didn't work for some reason.
class RatingAnswer < ActiveRecord::Base
belongs_to :rating_question
after_create :add_participant
...
protected
def add_participant
#participant = Participant.where(:user_id => self.user.id, :survey_id => self.rating_question.survey.id)
unless #participant.any?
#new_participant = Participant.create(:user_id => self.user.id, :survey_id => self.survey.rating_question.id)
end
end
end
The cool thing with associations is if you have deeply nested associations for instead
Survey has_many questions
Question has_many answers
Answer has_many responses
in order to fetch the survey id from within the responses model you can do
self.answer.question.survey.id
very nifty!
In Rails 3.2 I have been looking for a way to traverse the associations of an object within the before_add callback.
So basically my use case is:
class User < ActiveRecord::Base
has_and_belongs_to_many :meetings
end
class Meeting < ActiveRecord::Base
has_and_belongs_to_many :users
has_many :comments, :before_add => :set_owner_id
end
class Comment < ActiveRecord::Base
belongs_to :meeting
end
def set_owner_id(child)
child.owner_id = <<<THE USER ID for #user >>>
end
and I am creating a comment within the context of a user:
#user.meetings.first.comments.create
How do I traverse the associations from within the before_add callback to discover the id of #user? I want to set this at model level. I have been looking at proxy_association, but I may be missing something. Any ideas?
You should probably create the comment in the context of the meeting, no? Either way, you should handle this in the controller since you'll have no access to #user in your model.
#comment = Meeting.find(id).comments.create(owner_id: #user, ... )
But if you insist on your way, do this:
#comment = #user.meetings.first.comments.create(owner_id: #user.id)
Let's say you have the following models:
class User < ActiveRecord::Base
has_many :comments, :as => :author
end
class Comment < ActiveRecord::Base
belongs_to :user
end
Let's say User has an attribute name, is there any way in Ruby/Rails to access it using the table name and column, similar to what you enter in a select or where query?
Something like:
Comment.includes(:author).first.send("users.name")
# or
Comment.first.send("comments.id")
Edit: What I'm trying to achieve is accessing a model object's attribute using a string. For simple cases I can just use object.send attribute_name but this does not work when accessing "nested" attributes such as Comment.author.name.
Basically I want to retrieve model attributes using the sql-like syntax used by ActiveRecord in the where() and select() methods, so for example:
c = Comment.first
c.select("users.name") # should return the same as c.author.name
Edit 2: Even more precisely, I want to solve the following problem:
obj = ANY_MODEL_OBJECT_HERE
# Extract the given columns from the object
columns = ["comments.id", "users.name"]
I don't really understand what you are trying to achieve. I see that you are using polymorphic associations, do you need to access comment.user.name while having has_many :comments, :as => :author in your User model?
For you polymorphic association, you should have
class Comment < ActiveRecord::Base
belongs_to :author, :polymorphic => true
end
And if you want to access comment.user.name, you can also have
class Comment < ActiveRecord::Base
belongs_to :author, :polymorphic => true
belongs_to :user
end
class User < ActiveRecord::Base
has_many :comments, :as => :author
has_many :comments
end
Please be more specific about your goal.
I think you're looking for a way to access the user from a comment.
Let #comment be the first comment:
#comment = Comment.first
To access the author, you just have to type #comment.user and If you need the name of that user you would do #comment.user.name. It's just OOP.
If you need the id of that comment, you would do #comment.id
Because user and id are just methods, you can call them like that:
comments.send('user').send('id')
Or, you can build your query anyway you like:
Comment.includes(:users).where("#{User::columns[1]} = ?", #some_name)
But it seems like you're not doing thinks really Rails Way. I guess you have your reasons.
So, I've read in some book about tip "Use model association", which encourages developers to use build methods instead of putting ids via setters.
Assume you have multiple has_many relationships in your model. What's best practise for creating model then ?
For example, let's say you have models Article, User and Group.
class Article < ActiveRecord::Base
belongs_to :user
belongs_to :subdomain
end
class User < ActiveRecord::Base
has_many :articles
end
class Subdomain < ActiveRecord::Base
has_many :articles
end
and ArticlesController:
class ArticlesController < ApplicationController
def create
# let's say we have methods current_user which returns current user and current_subdomain which gets current subdomain
# so, what I need here is a way to set subdomain_id to current_subdomain.id and user_id to current_user.id
#article = current_user.articles.build(params[:article])
#article.subdomain_id = current_subdomain.id
# or Dogbert's suggestion
#article.subdomain = current_subdomain
#article.save
end
end
Is there a cleaner way ?
Thanks!
This should be a little cleaner.
#article.subdomain = current_subdomain
The only thing I can think of is merging the subdomain with params:
#article = current_user.articles.build(params[:article].merge(:subdomain => current_subdomain))