I have two models Post model and Comment model..First if a create a post it will have a post id of 1 then while creating a comment i can give association to the post using post_id equal to 1 but if i create a comment with post id of 2 which does not exist it would still go ahead and create a comment but with id of 'nil'..I want to ensure that the comment will be created only if the respective post_id is present.
class Post < ActiveRecord::Base
has_many :comments, dependent: destroy
end
class Comment < ActiveRecord::Base
belongs_to :post
validates_associated: post
end
As per my understanding validates_associated checks whether the validations in post model passes before creating a comment. Clarify me if i am wrong and what would be a appropriate solution for the above scenario?
First, the preferred way of setting the association b/w Post-Comment here is by :
def new
#product = Product.first
#comment = #product.comments.build
end
def create
#product = Product.find(params[:comment][:post_id])
#comment = #product.comments.create(comment_params)
end
For your particular scenario, I'm assuming that post_id is coming in params via some form or something, and then you wish to create a comment only if the post with that particular post_id exists. This can be done by adding following in Comment model:
validates :post, presence: true, allow_blank: false
OR
validate :post_presence, on: :create
def post_presence
errors.add(:post_id, "Post doesn't exist") unless Post.find(post_id).present?
end
You can even do the same thing at controller-side with before_action/before_filter hooks.
You can do this to validate the presence of post_id
class Comment < ActiveRecord::Base
belongs_to :post
validates :post_id, :presence => true
end
or to validate association, you can use
class Comment < ActiveRecord::Base
belongs_to :post
validates_presence_of :post
end
Related
I want to create an Invoice and the regarding InvoiceItems at the same time. While Invoice has_many :invoice_items and an InvoiceItem belongs_to :invoice. How do I perform such action in Rails 7 so that a User can add multiple invoiceItems to their invoice via Turbo? I dont need to know how TurboStreams and stuff work, since I am familiar, but I just cant get the InvoiceItems to be created at the same time as the Invoice.
I already found this post, but could not get any useful information out of it.
Models
Invoice.rb
class Invoice < ApplicationRecord
belongs_to :project
has_many :invoice_items, foreign_key: :invoice_id # not sure if this foreign_key is necessary
accepts_nested_attributes_for :invoice_items
end
invoice_item.rb
class InvoiceItem < ApplicationRecord
belongs_to :invoice
end
Controllers
Invoice_controller.rb
def create
#project = Project.find(params[:project_id])
#client = Client.find(params[:client_id])
#invoice = #project.invoices.new(invoice_params)
#invoice_item = #invoice.invoice_items.new
#invoice.invoice_items_attributes = [:invoice_id, :amount]
#invoice.client_id = #client.id
respond_to do |format|
if #invoice.save
....
def invoice_params
params.require(:invoice).permit(... :invoice_item, invoice_item_attributes: [:id, :invoice_id, :amount, ...])
end
Currently I try using a form_for inside of the Invoice form like:
<%= form.fields_for #invoice.invoice_items.build do |lorem| %>
Which gives me following error in the console (but saves the invoice as expected:
Unpermitted parameter: :invoice_item. Context: { controller: InvoicesController, action: create, request: #<ActionDispatch::Request:0x000000010a0c8d88>, params: {"authenticity_token"=>"[FILTERED]", "invoice"=>{..., "invoice_item"=>{"invoice_id"=>"", "amount"=>"3"}}, "button"=>"", "controller"=>"invoices", "action"=>"create", "user_id"=>"1", "client_id"=>"1", "project_id"=>"1"} }
notice that the invoice_id is not passed to the invoice_item.
Via console something like
#invoice = Invoice.new
#invoice.invoice_items.new(amount: "3", ...)
#invoice.save!
Does work weirdly but it does not translate to my code.
What am I doing wrong here?
# invoice_item_attributes is wrong
def invoice_params
params.require(:invoice).permit(... :invoice_item, invoice_item_attributes: [:id, :invoice_id, :amount, ...])
end
Should be
# invoice_items_attributes is right
def invoice_params
params.require(:invoice).permit(... :invoice_item, invoice_items_attributes: [:id, :invoice_id, :amount, ...])
end
Notice the missing 's'.
https://www.ombulabs.com/blog/learning/rails/nested-forms.html
After following the GoRails screencast on how to properly set nested form attributes in rails, I still came across errors. I eventually could trace them and found this neat post which game the hint to use inverse_of and autosave: true. I am not 100% sure what those do, even though I will read now to find out, but my stuff is working properly now :)
Modified Model
class Invoice < ApplicationRecord
belongs_to :project
has_many :invoice_items, inverse_of: :invoice, autosave: true
accepts_nested_attributes_for :invoice_items
...
I am building a simple expenses management app on rails 5.1.4. I am using the following five models.
Payees
class Payee < ApplicationRecord
has_many :expenses
validates :title, uniqueness: true, presence: true
end
Accounts
class Account < ApplicationRecord
before_save :update_balance
validates :balance, numericality: { greater_than_or_equal_to: 0 }
has_many :expenses
end
Budgets
class Budget < ApplicationRecord
belongs_to :categories
has_many :expenses, through: :categories
end
Categories
class Category < ApplicationRecord
validates :title, uniqueness: true, presence: true
has_many :expenses
has_one :budget
end
Expenses
class Expense < ApplicationRecord
belongs_to :categories
belongs_to :budgets
belongs_to :payees
belongs_to :accounts
validates :title, :value, presence: true
before_save :default_account
end
When I try to create a new expense I am facing a validation error
Validation failed: Categories must exist, Budgets must exist, Payees must exist, Accounts must exist
The issue is that all the above records exist. To explain my self let's say I am passing the params account_id: 1, payee_id: 1, category_id: 1. If I do:
Account.find(1) #=> Finds the record
Category.find(1) #=> also ok
Payee.find(1) #=> also ok
I am aware of the solution referred in this question (adding optional: true) but I don't get why I should do that while all of the above exist
Edit
The code that is raising the error is:
def create
#expense = Expense.create!(title: params[:expense]['title'],
value: params[:expense]['value'],
date: params[:expense]['date'],
comment: params[:expense]['comment'],
payee_id: params[:expense]['payee_id'],
category_id: params[:expense]['category_id'],
account_id: params[:expense]['account_id'])
end
The parameters that are passed through the form are
{"utf8"=>"✓",
"authenticity_token"=>"DWd1HEcBC3DhUahfOQcdaY0/oE+VHapxxE+HPUb0I6iSiqMxkz6l+vlK+1zhb66HnZ/vZRUVG4ojTdWUCjHtGg==",
"expense"=>{"title"=>"test", "value"=>"-20", "category_id"=>"1", "payee_id"=>"2", "date"=>"2018-01-21", "account_id"=>"1", "comment"=>""},
"commit"=>"Submit"}
I would first start by commenting out all your model validations, then creating an expense. Add back one model validation at a time, each time test creating an expense to see what validation is causing the error.
also you may want to change how you're creating the expense to something like below.
change your controllers create action to
def create
#expense = Expense.new(expense_params)
if #expense.save
flash[:success] = "expense created"
redirect_to expense_url(#expense.id)
else
render 'new'
end
end
next under your private method at the bottom of your controller you want to do something like this
private
# Never trust parameters from the scary internet, only allow the white list through.
def expense_params
params.require(:expense).permit(:title, :value, :date, etc...)
end
I finally found out where the problem is! It was the naming of the classes/models that raised the error. I had named my models on singular (Account, Category, etc) while all references are searching for plurals ( Accounts, Categories, etc). I had to re-do all migrations from the very beginning in order to make it work the proper way!
Thanks to everyone for spending the time though!
This is my first question here in stackoverflow, so please bear with me hehe.
I have three models: User, Post, and Comments.
# user.rb
class User < ApplicationRecord
has_many :posts
has_many :comments
end
# post.rb
class Post < ApplicationRecord
belongs_to :user
has_many :comments
end
# comments.rb
class Comment < ApplicationRecord
belongs_to :user
belongs_to :post
end
What i'm trying to achieve is to let the user comment only once in a post. If there is already an existing comment by the same user, it should not have accept the save/create.
So far, my idea is to create a model function where it iterate all of the exisiting post.comments.each then check all of the users, then if there is, then the comment is invalidated. Though I have no Idea how to do it.
If you have any idea (and perhaps the code snippets), please do share. Thanks in advance! :)
In your comment.rb
validates :user_id, uniqueness: { scope: [:post_id]}
This validation will make sure the combination user_id and post_id will be unique in your comments table.
Well, there are a couple of ways to do it.
Firstly, it is possible to validate uniqueness of user_id - post_id combinations in comments:
# app/models/comments.rb
class Comment < ActiveRecord::Base
# ...
validates_uniqueness_of :user_name, scope: :account_id
Another approach is to manually check for comment existance before creating a comment:
if Comment.exists?(user_id: current_user.id, post_id: params[:comment][:post_id])
# render error
else
Comment.create(params[:comment])
end
But in a concurrent environment both approaches may fail. If your application is using a concurrent server like puma or unicorn you will also need a database constraint to prevent creation of duplicated records. The migration will be as follows:
add_index :comments, [:user_id, :post_id], unique: true
What i have created is a "active" field in my topics table which i can use to display the active topics, which will contain at first the time the topic was created and when someone comments it will use the comment.created_at time and put it in the active field in the topics table, like any other forum system.
I found i similar question here
How to order by the date of the last comment and sort by last created otherwise?
But it wont work for me, im not sure why it wouldn't. And i also don't understand if i need to use counter_cache in this case or not. Im using a polymorphic association for my comments, so therefore im not sure how i would use counter_cache. It works fine in my topic table to copy the created_at time to the active field. But it wont work when i create a comment.
Error:
NoMethodError in CommentsController#create
undefined method `topic' for
Topic.rb
class Topic < ActiveRecord::Base
attr_accessible :body, :forum_id, :title
before_create :init_sort_column
belongs_to :user
belongs_to :forum
validates :forum_id, :body, :title, presence: true
has_many :comments, :as => :commentable
default_scope order: 'topics.created_at DESC'
private
def init_sort_column
self.active = self.created_at || Time.now
end
end
Comment.rb
class Comment < ActiveRecord::Base
attr_accessible :body, :commentable_id, :commentable_type, :user_id
belongs_to :user
belongs_to :commentable, :polymorphic => true
before_create :update_parent_sort_column
private
def update_parent_sort_column
self.topic.active = self.created_at if self.topic
end
end
Didn't realise you were using a polymorphic association. Use the following:
def update_parent_sort_column
commentable.active = created_at if commentable.is_a?(Topic)
commentable.save!
end
Should do the trick.
I need to link Comments to a Post. However the Comment could be (user generated) a simple text, (system generated) a link or an (system generated) image.
At first they all shared the same attributes. So I just needed to create a category attribute, and do different stuff with the text attribute based on that category.
example:
class Comment < ActiveRecord::Base
belongs_to :post
belongs_to :author, :class_name => "User"
CATEGORY_POST = "post"
CATEGORY_IMAGE = "image"
CATEGORY_LINK = "link"
validates :text, :author, :category, :post, :presence => true
validates_inclusion_of :category, :in => [CATEGORY_POST, CATEGORY_IMAGE, CATEGORY_LINK]
attr_accessible :author, :text, :category, :post
def is_post?
self.category == CATEGORY_POST
end
def is_link?
self.category == CATEGORY_LINK
end
def is_image?
self.category == CATEGORY_IMAGE
end
end
However this wil not suffice now, because I doesn't feel clean to dump every value in a generic "text" property. So I was thinking about create a polymorphic model (and if needed in a factory pattern). But when I googled about polymorphic models, I get examples like a Comment on a Post, but the same Comment on a Page, kind of relations. Is my understanding of polymorphic different (a model that acts different in different situations, compared to a model that acts the same under different scopes)?
So how would I set up this kind of relationship?
I was thinking of (and please correct me)
Post
id
Comment
id
post_id
category (a enum/string or integer)
type_id (references either PostComment, LinkComment or ImageComment based on category)
author_id
PostComment
id
text
LinkComment
id
link
ImageComment
id
path
User (aka Author)
id
name
But I have no clue how to setup the model so that I can call post.comments (or author.comments) to get all comments. A nice to have would be that the creation of a comment would be through comment and not link/image/postcomment (comment acting as the factory)
My main question is, how to setup up the activerecord models, so the relations stay intact (a author has comments and a post has comments. Comments being either a Link, Image or Postcomment)
I'm going to answer only your main question, the model setup. Given the columns and tables you used in your question, with the exception of Comment, you can use the following setup.
# comment.rb
# change category to category_type
# change type_id to category_id
class Comment < ActiveRecord::Base
belongs_to :category, polymorphic: true
belongs_to :post
belongs_to :author, class_name: 'User'
end
class PostComment < ActiveRecord::Base
has_one :comment, as: :category
end
class LinkComment < ActiveRecord::Base
has_one :comment, as: :category
end
class ImageComment < ActiveRecord::Base
has_one :comment, as: :category
end
with that setup, you can do the following.
>> post = Post.first
>> comments = post.comments
>> comments.each do |comment|
case comment.category_type
when 'ImageComment'
puts comment.category.path
when 'LinkComment'
puts comment.category.link
when 'PostComment'
puts comment.category.text
end
end