Rails 5.2
I have a Catalog model, with the following methods:
def current_items
....
end
def sales_items
....
end
There are more than a dozen methods, and I would like to do, in my helper, is to define an array
categories = ['current', 'sales', ....]
categories.each do |category|
m = "{category}_items"
#items = Catalog.m
...
end
But, I am getting an error:
undefined method 'm' for Catalog:Class
Any idea if this can be done?
Please try below code :-
class Catalog < ActiveRecord::Base
def self.current_items
puts "from current_items"
end
def self.sales_items
puts "from sales_items"
end
end
Then call using :-
if public
m = "#{category}_items"
#items = Catalog.public_send(m)
if private
m = "#{category}_items"
#items = Catalog.send(m)
thanks :)
Try public_send to call the public methods in class, use send if you want to call private methods as well but avoid using send if not needed
m = "#{category}_items"
Catalog.public_send(m)
Give it a try!
Related
In a Rails 5.1 app, I have a query object (PORO) named CoolProducts.
class CoolProducts
def self.call(relation = Product.all)
...
# return an instance of Product::ActiveRecord_Relation
end
end
Now I need to limit the found Products based on the fact the name matches a string.
The following works
CoolProducts.call.where("name ILIKE ?", "%#{string}%")
However, I'd like to encapsulate the matching login within the CoolProducts class allowing to do something like
CoolProducts.call.including_in_name(string)
But I'm not sure where to start from.
Any ideas?
It will be difficult if you want any of your methods to be chainable or return ActiveRecord::Relation.
If you consider explicitly fetching the records when you're done chaining being ok, this should work:
class CoolProducts
def initialize(relation)
#relation = relation
end
def self.call(relation = Product.all)
new(relation).apply_scopes
end
attr_reader :relation
alias_method :fetch, :relation
def including_in_name(string)
tap { #relation = relation.where("name ILIKE ?", string) }
end
def apply_scopes
tap { #relation = relation.where(price: 123) }
end
end
Usage:
CoolProducts.call.including_in_name(string).fetch
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'm working on the Meetup Api.
I would like to save some conferences from the API into my database.
The saving conferences depend of the parameters passing into the view to the controller :
<%= link_to 'See conferences', conferences_path(:title => "ParisRb")%> |
Then I call the good method to look for the good conferences (comparing to the params) among all the one received from the api.
I would like the methods to be very generic and to be able to save any conferences not only 'ParisRb'.
So I modify all my methods in this goal but there is one I can not modify, I don't know how.
This is my whole code. The one I'd like to modify is self.conferences_filter(data) wich is supposed to receive the params from the controller instead of 'ParisRb'. But I know that passing parameters from the controller to the model is not a good practice. So any idea is welcome :)
lib/api_meetup.rb
class ApiMeetup
BASE_URI = "https://api.meetup.com"
def events(urlname)
HTTParty.get(BASE_URI + "/#{urlname}/events")
end
end
conferences_controller.rb
def index
#call to the API
response = ApiMeetup.new.events(params[:title])
api_data = JSON.parse(response.body)
filtered_conferences = Conference.conferences_filter(api_data)
conferences = Conference.save_conferences_from_api(filtered_conferences)
#conferences = conferences.current_conferences
end
conference.rb
#Keep only requested conferences
def self.conferences_filter(data)
requested_conferences = []
data.each do |event|
if event["name"].include?('ParisRb') #This should receive params[:title] instead of 'ParisRb'
requested_conferences << event
end
end
requested_conferences
end
#Save requested conferences from the Meetup API
def self.save_conferences_from_api(conferences)
# data = data_from_api
conferences.each do |line|
conference = self.new
conference.title = line['name']
conference.date = format_date(line['time'])
conference.url = line['link']
if conference.valid?
conference.save
end
end
self.all
end
That's was actually quite obvious.
I just needed to pass to argument to my method :
filtered_conferences = Conference.conferences_filter(api_data, params[:title])
#Keep only requested conferences
def self.conferences_filter(data, title)
requested_conferences = []
data.each do |event|
if event["name"].include?(title)
requested_conferences << event
end
end
requested_conferences
end
Need a little help over here :-)
I'm trying to extend the Order class using a decorator, but I get an error back, even when I use the exactly same code from source. For example:
order_decorator.rb (the method is exactly like the source, I'm just using a decorator)
Spree::Order.class_eval do
def update_from_params(params, permitted_params, request_env = {})
success = false
#updating_params = params
run_callbacks :updating_from_params do
attributes = #updating_params[:order] ? #updating_params[:order].permit(permitted_params).delete_if { |k,v| v.nil? } : {}
# Set existing card after setting permitted parameters because
# rails would slice parameters containg ruby objects, apparently
existing_card_id = #updating_params[:order] ? #updating_params[:order][:existing_card] : nil
if existing_card_id.present?
credit_card = CreditCard.find existing_card_id
if credit_card.user_id != self.user_id || credit_card.user_id.blank?
raise Core::GatewayError.new Spree.t(:invalid_credit_card)
end
credit_card.verification_value = params[:cvc_confirm] if params[:cvc_confirm].present?
attributes[:payments_attributes].first[:source] = credit_card
attributes[:payments_attributes].first[:payment_method_id] = credit_card.payment_method_id
attributes[:payments_attributes].first.delete :source_attributes
end
if attributes[:payments_attributes]
attributes[:payments_attributes].first[:request_env] = request_env
end
success = self.update_attributes(attributes)
set_shipments_cost if self.shipments.any?
end
#updating_params = nil
success
end
end
When I run this code, spree never finds #updating_params[:order][:existing_card], even when I select an existing card. Because of that, I can never complete the transaction using a pre-existent card and bogus gateway(gives me empty blanks errors instead).
I tried to bind the method in order_decorator.rb using pry and noticed that the [:existing_card] is actuality at #updating_params' level and not at #updating_params[:order]'s level.
When I delete the decorator, the original code just works fine.
Could somebody explain to me what is wrong with my code?
Thanks,
The method you want to redefine is not really the method of the Order class. It is the method that are mixed by Checkout module within the Order class.
You can see it here: https://github.com/spree/spree/blob/master/core/app/models/spree/order/checkout.rb
Try to do what you want this way:
Create file app/models/spree/order/checkout.rb with code
Spree::Order::Checkout.class_eval do
def self.included(klass)
super
klass.class_eval do
def update_from_params(params, permitted_params, request_env = {})
...
...
...
end
end
end
end
Here is my one model..
CardSignup.rb
def credit_status_on_create
Organization.find(self.organization_id).update_credits
end
And here's my other model. As you can see what I wrote here is an incorrect way to pass the var
def update_credits
#organization = Organization.find(params[:id])
credit_count = #organization.card_signups.select { |c| c.credit_status == true}.count
end
If it can't be done by (params[:id]), what can it be done by?
Thanks!
Ideally the data accessible to the controller should be passed as parameter to model methods. So I advise you to see if it is possible to rewrite your code. But here are two possible solutions to your problem. I prefer the later approach as it is generic.
Approach 1: Declare a virtual attribute
class CardSignup
attr_accessor call_context
def call_context
#call_context || {}
end
end
In your controller code:
def create
cs = CardSignup.new(...)
cs.call_context = params
if cs.save
# success
else
# error
end
end
In your CardSignup model:
def credit_status_on_create
Organization.find(self.organization_id).update_credits(call_context)
end
Update the Organization model. Note the change to your count logic.
def update_credits
#organization = Organization.find(call_context[:id])
credit_count = #organization.card_signups.count(:conditions =>
{:credit_status => true})
end
Approach 2: Declare a thread local variable accessible to all models
Your controller code:
def create
Thread.local[:call_context] = params
cs = CardSignup.new(...)
if cs.save
# success
else
# error
end
end
Update the Organization model. Note the change to your count logic.
def update_credits
#organization = Organization.find((Thread.local[:call_context] ||{})[:id])
credit_count = #organization.card_signups.count(:conditions =>
{:credit_status => true})
end
Use an attr_accessor.
E.g.,
class << self
#myvar = "something for all instances of model"
attr_accessor :myvar
end
#myothervar = "something for initialized instances"
attr_accessor :myothervar
then you can access them as ModelName.myvar and ModelName.new.myvar respectively.
You don't say whether you're using Rails 2 or 3 but let's assume Rails 2 for this purpose (Rails 3 provides the a new DSL for constructing queries).
You could consider creating a named scope for in your Organization model as follows:
named_scope :update_credits,
lambda { |id| { :include => :card_signup, :conditions => [ "id = ? AND card_signups.credit_status = TRUE", id ] } }
And then use it as follows:
def credit_status_on_create
Organization.update_credits(self.organization_id)
end
Admittedly I don't quite understand the role of the counter in your logic but I'm sure you could craft that back into this suggestion if you adopt it.