I have a Product model which I just basically use to interface with Stripe, it only has a stripe_product_id column.
I have multiple controllers that are dealing with products, and in every case, when a product or multiple products are retrieved, I do something like this:
#product = Product.find(params[:id]
#stripe_product = Stripe::Product.retrieve(#product.stripe_product_id)
#product.name = #stripe_product.name
# ...
render json: ProductSerializer.new(#product, {}).serializable_hash.to_json
It's not really DRY, and in this case it even works, however, I have similar structures with other Stripe entities (prices, customers) as well.
Products have many prices, and when I want to include them through the product serializer, that process obviously doesn't go through a controller's show method, but rather tries to work directly on the model.
How can I tweak a model to include attributes retrieved from a third party API, in this case Stripe?
I feel like this kind of data belongs more to the model than to a bunch of controllers, since I basically use it in ways models are used.
I would do it like this, I didn't test it, but leave it for you, I hope you get the idea
class Product < ApplicationRecord
delegate :name, to :#stripe_wrapper
def stripe_wrapper
#stripe_wrapper ||= Stripe::Product.new(self.stripe_product_id).retrieve
end
end
module Services
class StripeWrapper
delegate :name, to :#result
Product = Struct.new(:name)
def initialize(product_id)
#product_id = product_id
#result = Product.new('')
end
def retrieve
# API call to stripe
# set fields to result
# result.name = json['name']
end
end
end
and in your controller is skinny.
if you calling somewhere #product.name in your serializer it will be available
class ProductController < ApplicationController
def show
#product = Product.find(params[:id])
render json: ProductSerializer.new(#product, {}).serializable_hash.to_json
end
end
Related
Developing rails app for both api and front end. so we have products controller for api and products controller for the front and Product model is one for both.
Like that
class Api::V1::ProductsController < ActionController::API
def create
#product.save
end
end
class ProductsController < ActionController::Base
def create
#product.save
render #product
end
end
class Product < ActiveRecord::Base
def weight=(value)
weight = convert_to_lb
super(weight)
end
end
Basically in product we have 'weight field' and this field is basically capture weight from the warehouse. it will be different unit for the user. so i'm going to save whatever weight is capture by unit, its lb,g or stone but it will convert to lb and store into database.
So i write the overide method for the conversation. but i want this override method should only call for front app only and not for the api. because api will always post weight in lb(its need to be convert in client side)
Can you guys anyone suggest the solution? what should i use or what should i do for this kind of scenario.suggest if its any other solution for that kind of situation as well. Thanks in advance.
It's better to keep Product model as simple as possible (Single-responsibility principle) and keep weight conversion outside.
I think it would be great to use Decorator pattern. Imagine class that works like this:
#product = ProductInKilogram.new(Product.find(params[:id]))
#product.update product_params
#product.weight # => kg weight here
So, you should use this new ProductInKilogram from Api::V1::ProductsController only.
You have options to implement that.
Inheritance
class ProductInKilogram < Product
def weight=(value)
weight = convert_to_lb
super(weight)
end
end
product = ProductInKilogram.find(1)
product.weight = 1
It's easy, but complexity of ProductInKilogram is high. For example you can't test such class in an isolation without database.
SimpleDelegator
class ProductInKilogram < SimpleDelegator
def weight=(value)
__getobj__.weight = convert_to_lb(value)
end
end
ProductInKilogram.new(Product.find(1))
Plain Ruby (My Favourite)
class ProductInKilogram
def initialize(obj)
#obj = obj
end
def weight=(value)
#obj.weight = convert_to_lb(value)
end
def weight
convert_to_kg #obj.weight
end
def save
#obj.save
end
# All other required methods
end
Looks a little bit verbose, but it is simple. It's quit easy to test such class, because it does nothing about persitance.
Links
Single-responsibility principle
Delegate gem
Decorator Pattern in Ruby
I am trying to assign session values to model object as below.
# models/product.rb
attr_accessor :selected_currency_id, :selected_currency_rate, :selected_currency_icon
def initialize(obj = {})
selected_currency_id = obj[:currency_id]
selected_currency_rate = obj[:currency_rate]
selected_currency_icon = obj[:currency]
end
but this works only when I initialize new Product object
selected_currency = (session[:currency].present? ? session : Currency.first.attributes)
Product.new(selected_currency)
While, i need to set these setter methods on each product object automatically even if was fetched from Database.(active record object) ie. Product.all or Product.first
Earlier i was manually assigning values to each product object after retrieving it from db on controller side.
#products.each do |product|
product.selected_currency_id = session[:currency_id]
product.selected_currency_rate = session[:currency_rate]
product.selected_currency_icon = session[:currency]
end
But then i need to do it on every method where product details need to be displayed. Please suggest a better alternative to set these setter methods automatically on activerecord objects.
I don't think you really want to do this on the model layer at all. One thing you definitely don't want to do is override the initializer on your model and change its signature and not call super.
Your model should only really know about its own currency. Displaying the price in another currency should be the concern of another object such as a decorator or a helper method.
For example a really naive implementation would be:
class ProductDecorator < SimpleDelegator
attr_accessor :selected_currency
def initialize(product, **options)
# Dynamically sets the ivars if a setter exists
options.each do |k,v|
self.send "#{k}=", v if self.respond_to? "#{k}="
end
super(product) # sets up delegation
end
def price_in_selected_currency
"#{ price * selected_currency.rate } #{selected_currency.icon}"
end
end
class Product
def self.decorate(**options)
self.map { |product| product.decorate(options) }
end
def decorate(**options)
ProductDecorator.new(self, options)
end
end
You would then decorate the model instances in your controller:
class ProductsController
before_action :set_selected_currency
def index
#products = Product.all
.decorate(selected_currency: #selected_currency)
end
def show
#product = Product.find(params[:id])
.decorate(selected_currency: #selected_currency)
end
private
def set_selected_currency
#selected_currency = Currency.find(params[:selected_currency_id])
end
end
But you don't need to reinvent the wheel, there are numerous implementations of the decorator pattern like Draper and dealing with currency localization is complex and you really want to look at using a library like the money gem to handle the complexity.
I want some of my model attributes to predefined dynamically. I have various models.And now I want My Bill model to create objects using other model instances.
Models :
leave.rb # belongs_to :residents
resident.rb # has_many:leaves,has_many:bills,has_one:account
bill.rb # belongs_to:residents
rate_card.rb # belongs_to:hostel
account.rb # belongs_to:resident
hostel.rb
now here is my bills controller create method :
def create
#bill = Resident.all.each { |resident| resident.bills.create(?) }
if #bill.save
flash[:success]="Bills successfully generated"
else
flash[:danger]="Something went wrong please try again !"
end
end
I want to build bill using all of the models eg:
resident.bills.create(is_date:using form,to_date:using form,expiry_date:using form,amount:30*(resident.rate_card.diet)+resident.rate_card.charge1+resident.rate_card.charge2)+(resident.account.leaves)*10+resident.account.fine)
///////Is this possible ?
And how to use strong params here ?
Pls help me out thxx..
I think the Rails way for this logic you want is with callbacks if you want calculated attributes either on create, update or delete, meaning attributes that depend on other models. For instance:
class Bill < ActiveRecord::Base
...
before_create :set_amount
...
protected
def set_amount
self.amount = 30 * self.resident.rate_card.diet + self.resident.rate_card.charge1 + self.resident.rate_card.charge2 + (self.resident.account.leaves) * 10 + self.resident.account.fine
end
end
If you want this logic to be used when updating the record also, then you should use before_save instead of before_create.
After you do this, you should accept the usual params (strong) of Bill model, as in:
def bill_params
params.require(:bill).permit(:is_date, :to_date, :expiry_date)
end
So your create call would be like:
resident.bills.create(bill_params)
Also, be wary of your create action, you should probably create a method either on your Bill or your Resident model that uses transactions to create all bills at the same time because you probably want either every bill created or none. This way you won't have the Resident.all.each logic in your BillsController.
create takes a hash, you can:
create_params = { amount: 30*(resident.rate_card.diet) }
create_params[:some_field] = params[:some_field]
# and so on
resident.bills.create(create_params)
or:
obj = resident.bills.build(your_strong_parameters_as_usual)
obj.amount = # that calculation
obj.save!
I'm confused at your syntax of your controller. #bill is being set to the value of a loop, which feels off. Each loops return the enumerable you cycle through, so you'll end up with #bill = Resident.all with some bills being created on the side.
What your controller really wants to know is, did my many new bills save correctly?
This seems like a perfect place to use a ruby object (or, colloquially, a Plain Old Ruby Object, as opposed to an ActiveRecord object) to encapsulate the specifics of this bill-generator.
If I'm reading this right, it appears that you are generating many bills at once, based on form-inputted data like:
is_date
to_date
expiry_date
...as well as some data about each individual resident.
Here's the model I'd create:
app/models/bill_generator.rb
class BillGenerator
include ActiveModel::Model
# This lets you do validations
attr_accessor :is_date, :to_date, :expiry_date
# This lets your form builder see these attributes when you go form.input
attr_accessor :bills
# ...for the bills we'll be generating in a sec
validates_presence_of :is_date, :to_date, :expiry_date
# You can do other validations here. Just an example.
validate :bills_are_valid?
def initialize(attributes = {})
super # This calls the Active Model initializer
build_new_bills # Called as soon as you do BillGenerator.new
end
def build_new_bills
#bills = []
Resident.all.each do |r|
#bills << r.bills.build(
# Your logic goes here. Not sure what goes into a bill-building...
# Note that I'm building (which means not-yet-saved), not creating
)
end
def save
if valid?
#bills.each { |b| b.save }
true
else
false
end
end
private
def bills_are_valid?
bill_validity = true
#bills.each do |b|
bill_validity = false unless b.valid?
end
bill_validity
end
end
Why all this mess? Because in your controller you can do...
app/controllers/bill_controller.rb
def create
#bill_generator = BillGenerator.new(bill_generator_params)
if #bill_generator.save?
# Redirect to somewhere with a flash?
else
# Re-render the form with a flash?
end
end
def bill_generator_params
params.require(:bill_generator).permit(:is_date, :to_date, :expiry_date)
# No extra garbage. No insecurity by letting all kinds of crud through!
end
...like a BillGenerator is any old object. Did it save? Great. It didn't, show the form again.
Now, my BillGenerator won't just be copy-and-paste. Your 'build_new_bills' probably will have some of that math you alluded to, which I'll leave to you.
Let me know what you think!
you can do it by using params.permit! as this allows any parameters to be passed. here's an example:
def create
...
#bill = Resident.all.each { |resident| resident.bills.create(any_params) }
end
private
def any_params
params.permit!
end
be careful with this of course, as you are opening this up to potential exploits.
I'm coming from the .NET world and I'm trying to figure out what the 'Rails Way' to pass an object across tiers in a multi-tier application.
I'm writing a multi carrier pricing API. Basically in my price controller I have access to the following parameters params[:carrier], params[:address_from], params[:address_to], params[:container_type], etc. I have a validation library, a compliance library and a price-finder library that each deal with a subset of the params.
In .NET the params would be encapuslated in data transfer objects (DTOs) or contracts. Before calling any of the libraries, they would be converted to domain objects (DOs) and each library would work on the DOs, thus avoiding a tight coupling on the DTOs. Ruby programming recommands the use of 'duck typing', so my libraries could work directly on params (even though you would access symbols and not objects/properties). Or should I marshall my params into a PriceRequest object and have my libraries work on the PriceRequest type?
Option 1:
class PricesController < ApplicationController
def get
CarrierValidator.validate(params)
...
end
end
class CarrierValidator
def self.validate(params)
raise CarrierError if !Carrier.find_by_name(params[:carrier_name]).exists?
end
end
Option 2:
class PricesController < ApplicationController
def get
pricesRequest = PricesRequest.new(carrier_name: params[:carrier_name], ...)
pricesRequest.validate
...
end
end
class PriceRequest
attr_accessor : ...
def initalize
...
end
def validate
CarrierValidator.validate(self.carrier_name)
end
end
class CarrierValidator
def self.validate(carrier_name)
raise CarrierError if !Carrier.find_by_name(carrier_name).exists?
end
end
TIA,
J
You should create a type. I would use ActiveModel to encapsulate the data (attributes) & business logic (validations & maybe some layer-specific methods for processing the data).
Basically, you want to be able to do Rails-y things in the controller like:
def get
price_request = PriceRequest.new(params[:price_request])
if price_request.valid?
# do something like redirect or render
else
# do something else
end
end
so you want to declare:
class PriceRequest
include ActiveModel::Model
attr_accessor :carrier, :address_from, :address_to, :container_type
validates :carrier, presence: true
validate :validate_address_from
def validate_address_from
# do something with errors.add
end
# and so on
This is a good place to start: http://edgeguides.rubyonrails.org/active_model_basics.html
More details in the API: http://api.rubyonrails.org/classes/ActiveModel/Model.html
Hope that points you in the right direction...
I have a patient model where I defined:
def weight
###Some Code###
end
def height
###Some Code###
end
Inside my patient serializer, I am also sending both height and weight to my angularJS app when performing a /GET.
Now, willing to add some date filters to my angularJS app, I have to change my patient model methods to be this way:
def weight(date)
###Some Code###
end
def height(date)
###Some Code###
end
I was wondering if there is a possibility to tell my RoR app to send me both weight and height at a chosen date?
I was thinking about creating a new Controller to do the work but I want to avoid this if it is possible.
Make weight and height virtual attributes on the model. They will be set in memory on the instance when you call setter methods. They should serialize as normal. Something like:
class Patient
attr_accessor :weight, :height
def filter_weight(date)
#weight = ### previous result of #weight(date) Some Code###
end
def filter_height(date)
#height = ###previous result #height(date) Some Code###
end
end
Then you would send the date as parameters in your GET request.
class PatientsController
def show
patient = Patient.find(params[:id])
patient.filter_weight(params[:date])
patient.filter_height(params[:date])
render json: patient, status: 200
end
end
You could probably refactor this into a method Patient#filter_weight_and_height(date)