I have two Model level functions that populate two arrays, my_favorite_brands and my_favorites. They are defined as follows:
def self.my_favorite_brands
brand_list = Array.new
Favorite.my_favorites.each do |favorite|
brand_list.push(favorite.style.shoe.brand)
end
brand_list.uniq
end
And here is my_favorites:
def self.my_favorites
Favorite.where(:user => current_user)
end
I want to print out each Brand in my_favorite_brands and while doing so, for each Brand print out all of it's associated Favorites in my_favorites. The relation between the two models Brand and Favorite is the following. Brand has many Shoes which has many Styles. Favorite belongs to Style and it belongs to User. Here is some probably non-functional pseudo-ish (in that it doesn't really work) code that emulates what I want to do.
#Controller stuff
#fav_brands = Brand.my_favorite_brands
#fav_favorites = Favorite.my_favorites
#in the view
favorites_by_brand = Array.new
#fav_brands.each do |brand|
favorites_by_brand = #fav_favorites.map do |favorite|
unless favorite.style.shoe.brand == brand
#fav_favorites.delete("favorite")
end
favorites_by_brand.each do |favorite|
puts favorite.style
end
end
I am trying to create a complete list of favorites where favorite.style.shoe.brand is equal to the current brand I am iterating over, so that I can display the styles by Brand.
I figured out a way to accomplish what I want to accomplish, although it's probably not Ideal .
styles_of_favorites = #fav_favorites.map {|favorite| favorite.style}
#fav_brands.each do |brand|
brand.shoes.each do |shoe|
shoe.style.each do | style|
if styles_of_favorites.include?(style)
puts style
end
end
end
end
Related
I have model Board and BoardController where i can find all boards of my project.
All records have filled "board_layout" column with enum.
Now i have show method in BoardController and i want to load there different data from different table depending on board_layout column value.
I could do it like this:
def show
#board = Board.find(params[:id])
if #board.board_layout == 1
#tasks = Car.where(board_id: #board.id)
elsif #board.board_layout == 2
#tasks = Truck.where(board_id: #board.id)
end
end
But it's not elegant + it is not DRY (i need to use some sort of if statement anytime when i want to do something with those 2 tables).
So i have tried to create Concern and create case statement inside, now it looks like:
def show
#board = Board.find(params[:id])
#tasks = get_class_name(#board.board_layout).where(board_id: #board.id)
end
# inside my concern
def get_class_name(scope)
case scope
when 1
Car
when 2
Truck
end
end
My Question:
Is there better way to do it? Is my solution safe and clear?
What is the best solution to resolve problem like this?
I would appreciate any help.
maybe you can abstract that out into a class, so you can define multiple layout and their correspondent classes, like:
class LayoutClassGetter
CLASS_BY_LAYOUT = { '1' => Car, '2' => Truck }.freeze
def initialize(layout_number)
#layout_number = layout_number
end
def layout_class
CLASS_BY_LAYOUT[#layout_number]
end
def self.layout_class(layout_number)
new(layout_number).layout
end
end
And then use it:
def show
#board = Board.find(params[:id])
#tasks = layout_class(#board.board_layout).where(board_id: #board.id)
end
def layout_class(scope)
LayoutClassGetter.layout_class(scope)
end
How can I add variables to an existing obejct?
I have a list of chat rooms and I want to add a new variable for each chat to use at my view:
Example I want to add total users of chat
def index
chats_all = ChatRoom.all
#chats = Array.new
chats_all.each |chat|
chat.total_users = 10
#chats << chat
end
#chats
end
total_users is not an attribute of ChatRoom class.
[EDIT - explaim better after #jvillian great awnser]
I don't want total_users as an attribute of User class.
I just want to add as a variable to use at this one single page. For json rails already let my add new attributes to objects. Just need to use as_json().map and a merge()
Example:
def index
chats = chats.as_json().map {
|chat|
chat.merge(
total_users: 10
}
response = { chats: chats }
render json: response
end
Now I got an json with chats and each chat has total_users attribute.
I want to know if I can do something like this with objects, just add a temporary variable to use at index page.
Try
class ChatRoom < ActiveRecord::Base
attr_accessor :total_users
end
You can read more in the docs.
Then, index could look like:
def index
#chats = ChatRoom.all.map do |chat|
chat.total_users = 10
chat
end
end
Alternatively, I would be tempted to do something like:
class ChatRoom < ActiveRecord::Base
TOTAL_USERS = 10
attr_accessor :total_users
def total_users
#total_users || TOTAL_USERS
end
end
And then:
def index
#chats = ChatRoom.all
end
Now, you'll get
#chats.first.total_users
=> 10
You can set total_users to something else if you like, but it will default to 10.
Here's a potential approach using OpenStruct:
def index
#chats = ChatRoom.all.map do |chat|
OpenStruct.new(
chat.
attributes.
merge!(total_users: 10)
)
end
end
Now, you can do:
#chats.each do |chat|
puts chat.total_users
end
which will return 10.
BTW and TBH, I do something like that last sort of thing (using OpenStruct or custom decorators) all the time. In my more recent apps, views never have direct access to models.
Maybe you want to send the response to the view as an array and scan to show informations?
def index
#chats = ChatRoom.all.as_json().map { |chat| chat.merge("total_users" => 10) }
end
Then access #chats, which is actually an array of hashes, view:
<% #chats.each do |chat| %>
<p><%= chat["total_users"] %></p>
<% end %>
You can check how #chats is structured by <p><%= #chats %></p>
I maybe made some syntax error.
To create temporary custom Objects without add new attributes to database Struct solve my problem.
I can create a Struct with chat room info and total users
chat_info = Struct.new(:name, :total_users, :messages)
chat_temp = []
chats = ChatRoom.where(condition)
chats.each do |chat|
chat_temp << chat_info.new("nome", 100, messages)
end
I have a resource :posts, which I show one at a time in show.html.erb
Suppose I have ten posts, each with an :id going from 1-10. If I delete post #2, then my posts will be 1,3,4,5,6,7,8,9,10. If I create ten posts and delete them all, then the next post :id would be [1,3..10,21] but I would only have 11 posts.
I want to show the post number that's in the application and put it in the view against a total number of posts. So if you were looking at post #3, it might have an :id of 3, but it is post #2 in the database.
Here's what I tried so far:
posts_controller.rb
def show
...
#post = Post.friendly.find(params[:id])
#total_posts = Post.all.count.to_i
#posts_array = Post.pluck(:id).to_a
...
end
views/posts/show.html.erb
<%= #post.id %> of <%= #total_posts %> /
models/post.rb
def next
Post.where("id > ?", id).order(id: :asc).limit(1).first
end
def prev
Post.where("id < ?", id).order(id: :desc).limit(1).first
end
However, showing the :id of a resource is a security issue so I don't know how to do it better.
How can I make it so the show.html.erb view only shows the current index order of the total amount of resources as compared to the post_id?
An efficient way to do this could be
# app/controllers/posts_controller.rb
def show
#post = Post.friendly.find(params[:id])
#total_posts = Post.count
#post_index = Post.where("id <= ?", #post.id).count
end
# app/views/posts/show.html.erb
. . .
<%= #post_index %> of <%= #total_posts %>
. . .
You should avoid loading all posts (or even their id) if you can. This will become more and more expensive as the number of posts grows and will eventually become a bad bottleneck for performance.
If you're trying to find the 'array index' of a record (so to speak) you can do this:
Agency.order(id: :asc).offset(params[:index]).limit(1)
You don't really want to do any other way because then it will load EVERY record into rails which will be very slow. It's better to ask the database for only a single record (which is what 'offset' does). Just replace params[:index] with whatever the name of the params is, whether its params[:id], etc.
I did just want to address one thing you said:
However, showing the :id of a resource is a security issue so I don't know how to do it better
That's not a security issue. The app should be designed in a way where the ID of a resource is not special or "secret." If you have an ID of a record, your controller should work such that it "authorizes" certain actions and won't let you do something you're not supposed to (like a user deleting a post).
If you REALLY need to do this, then just hide the ID and use a slug instead, like example.com/this-is-a-post-slug. This can be done quite easily
Edit To answer your specific question...
ids = Agency.order(id: :asc).pluck(:id)
#post_index = ids.find_index(#post.id)
#next_post = ids[#post_index + 1]
#prev_post = ids[#post_index - 1]
You can now use #post_index in your view.
Note: #prev_post and #next_post will be nil when the page doesn't exist (i.e. the "next post" when you're on the last page), so you will need to check that.
Just try it:
def show
...
#post = Post.friendly.find(params[:id])
#total_posts = Post.count # this will return integer type data
#posts_array = Post.pluck(:id) # you don't need to_a as .pluck returns array
...
For the next part you could write:
def next
self.class.where("id > ?", id).limit(1).first # this use of id is secured.
end
def prev
self.class.where("id < ?", id).order(id: :desc).limit(1).first
end
Could someone take a look at my code and let me know if there is a better way to do this, or even correct where I'm going wrong please? I am trying to create a new row for each venue and variant.
Example:
venue_ids => ["1","2"], variant_ids=>["10"]
So, I would want to add in a row which has a venue_id of 1, with variant_id of 10. And a venue_id of 2, with variant_id of 10
I got this working, and it's now passing in my two arrays. I think I am almost there I'm not sure the .each is the right way to do it, but I think that I'm on the right track haha. I have it submitting, however, where would I put my #back_bar.save? because this might cause issues as it won't redirect
Thanks in advance.
def create
#back_bar = BackBar.new
#venues = params[:venue_ids]
#productid = params[:product_id]
#variants = params[:variant_ids]
# For each venue we have in the array, grab the ID.
#venues.each do |v|
#back_bar.venue_id = v
# Then for each variant we associate the variant ID with that venue.
#variants.each do |pv|
#back_bar.product_variant_id = pv
# Add in our product_id
#back_bar.product_id = #productid
# Save the venue and variant to the DB.
if #back_bar.save
flash[:success] = "#{#back_bar.product.name} has been added to #{#back_bar.venue.name}'s back bar."
# Redirect to the back bar page
redirect_to back_bars_path
else
flash[:alert] = "A selected variant for #{#back_bar.product.name} is already in #{#back_bar.venue.name}'s back bar."
# Redirect to the product page
redirect_to discoveries_product_path(#back_bar.product_id)
end
end # Variants end
end # Venues end
end
private
def back_bar_params
params.require(:back_bar).permit(:venue_id,
:product_id,
:product_variant_id)
end
as i said in comments
this is untested code and just showing you how it's possible to do with ease.
class BackBar
def self.add_set(vanue_ids, variant_ids)
values = vanue_ids.map{|ven|
variant_ids.map{|var|
"(#{ven},#{var})"
}
}.flatten.join(",")
ActiveRecord::Base.connection.execute("INSERT INTO back_bars VALUES #{values}")
end
end
def create
# use in controller
BackBar.add_set(params[:venue_ids], params[:variant_ids])
# ...
end
I have an array of values, like:
- #colors.each do |color|
= check_box_tag 'colors[]', color.id
Every time, when I update the values from those checkbox in the DB table, I am doing that by this way:
UserColor.delete_all(['user_id = ?'], current_user.id) #delete all user's rows
unless params[:colors].nil?
params[:colors].each do |color|
UserColor.create(:user_id => current_user.id, :color_id => color)
end
end
It's the working solution, but I don't like it very much. That's why I would like to ask you, how do you solve this problem and if doesn't exist any some better way to do it.
Thanks
class User
has_many :colors, through: :user_colors
end
in controller
if params[:colors]
user = current_user
user.color_ids = params[:colors]
user.save
end
or u can try
current_user.update_attribute(:color_ids, params[:colors]) if params[:colors]
I would define a method in the User model
def update_colors!(new_color_ids)
# get an array of the current color ids
old_color_ids = user_colors.map(&:color_id)
# destroy colors that appear in the old list but not in the new
user_colors.where(color_id: old_color_ids - new_color_ids).destroy_all
# add colors that appear in the new list but not in the old
(new_color_ids - old_color_ids).each do |add_color_id|
user_colors.create!(color_id: add_color_id)
end
end
From the controller, just call
current_user.update_colors!(params[:colors])
.