I have an app that models a House. The House has_many Rooms, Rooms has_many Lights and Small_appliances, etc. I also have a controller called Calculator that is how the app is accessed. Data is added to the house (and its rooms) using the Calculator controller. Then a report is generated, which is located at app/views/calculator/report.html.erb.
My question is where should all the calculations and logic for the report go? Currently I have it all in the view, with some things in calculator_helper. Normally this would go in the model, right? But Calculator doesn't have a model that was generated. What is the standard for this?
Here is the calculator controller.
class CalculatorController < ApplicationController
def index
end
def save_house
#house = House.new(params[:house])
respond_to do |format|
if #house.save
format.html { render :action => 'add_rooms', :id => #house }
format.xml { render :xml => #house, :status => :created, :location => #house }
else
format.html { render :action => 'index' }
format.xml { render :xml => #house.errors, :status => :unprocessable_entity }
end
end
end
def add_rooms
#house = House.find(params[:id])
#rooms = Room.find_by_house_id(#house.id)
rescue ActiveRecord::RecordNotFound
logger.error("Attempt to access invalid house #{params[:id]}")
flash[:notice] = "You must create a house before adding rooms"
redirect_to :action => 'index'
end
def add_room
#room = Room.new(params[:room])
#house = #room.house
respond_to do |format|
if #room.save
flash[:notice] = "Room \"#{#room.name}\" was successfully added."
format.html { render :action => 'add_rooms' }
format.xml { render :xml => #room, :status => :created, :location => #room }
else
format.html { render :action => 'add_rooms' }
format.xml { render :xml => #room.errors, :status => :unprocessable_entity }
end
end
rescue ActiveRecord::RecordNotFound
logger.error("Attempt to access invalid house #{params[:id]}")
flash[:notice] = "You must create a house before adding a room"
redirect_to :action => 'index'
end
def report
flash[:notice] = nil
#house = House.find(params[:id])
#rooms = Room.find_by_house_id(#house.id)
rescue ActiveRecord::RecordNotFound
logger.error("Attempt to access invalid house #{params[:id]}")
flash[:notice] = "You must create a house before generating a report"
redirect_to :action => 'index'
end
end
There are a few ways to approach it, but the logic certainly does not belong in the view. You have the various models associated with one another in a clear hierarchy with the top of the hierarchy being the House model, if I am reading your description correctly. That being the case, I would add an appropriate method of set of methods to the House model that may be composed of calls to calculation methods in the Room models associated with a given House instance and on down the line of association. That ways the relevant calculation can be performed at each level and through composing one or more methods at the House model level you are able to have a clean, expressive and maintainable way to deal with calculations.
One thing to do, as well, would be to make sure that any calculations that can be performed by the DB are. For example, if there is a calculation that a Room model can do by simply querying it's own data then by all means push that computational burden to the DB using the ability of ActiveRecord to invoke such lower level calculation logic. Check out the API docs for the details.
I would look very carefully at the logic you want and see how it can be pushed into the model since that is probably where it belongs, close to the actual data of the calculations, and within the class structures that represent that data specifically; I would not create a model just to handle the calculation logic unless you really need to store the calculations persistently for some reason.
I would create a class in RAILS_ROOT/lib/ called, for example, Calculator and put the code in there.
Classes in /lib/ should be loaded an available anywhere in your app.
You can also create a plain ruby object in /app/models/. There's no reason they all have to inherit from ActiveRecord::Base
Ok, now I can see the code posted. I can see the calculator_controller actually has no calculations in it, are they in the views?. Try this approach:
Write a test that sets up an object which will return the results you need to return to the user of the web page, given a house, rooms or whatever else it needs.
Build a model (in models) to make that test pass.
Modify your controller code above to use your new calculator model
Modify the tests of your controller so they also pass. These tests, of course, do not need to test any business logic.
My prior respose:
If the business logic is fairly simple and only used behind this web app, then you can put it in your app/models folder.
class MyCoolClass
def initialize(clues)
#other_things = OtherThing.all
end
def do_cool_thing; end
def calculate_coolness
#other_things.length
end
end
Then in your controller, create an instance of your model
def index
#mcc = MyCoolClass "A clue as to what I want"
render
end
Then in your templates you can access it
<%=h #mcc.calculate_coolness %>
Note that #other_things is an instance__variable of MyCoolClass and generally not accessible to the templates without accessor methods being defined
This all depends on what kind of data you're creating. What does the calculator controller look like?
You can create your own classes in /lib and use them in your models, which can be a good way to separate out logic from the controller/helpers. Is there a reason why you couldn't put some of the logic in the models?
Related
I have a few hours with something that is probably very easy.
I have a nested model
resources :grades do
resources :students
end
So I defined
before_action :set_grade, except: [:mass_input]
to my students_controller
def set_grade
#grade = Grade.find(params[:grade_id])
end
I'm very good with this, the problem is that now I'm using another action that takes :grade_id from another source, so I cant use set_grade, instead I'm passing the id with javascript. Works.
My problem appears here, when I try to call to create method, I'm probably doing it wrong ..
def mass_input
#grade = Grade.find(#data['grade'])
#data = JSON.parse(params[:form_data])
#is this create way ok or I'm overriding???
Student.create(:rut => #data['mass_students'][1][0], :nombre => #data['mass_students'][1][1], :apellido => #data['mass_students'][1][2])
end
This is my create action
def create
#student = Student.new(student_params)
#grade.students << #student
respond_to do |format|
if #student.save
format.html { redirect_to school_grade_path(#grade.school,#grade), notice: 'Alumno creado con éxito.' }
format.json { render :show, status: :created, location: #student }
else
format.html { render :new }
format.json { render json: #student.errors, status: :unprocessable_entity }
end
end
end
By this way code works but this line is not working
#grade.students << #student
#grade is not passing from mass_input to create. I think I'm not calling create properly but I cant find how to do it , because is not redirecting neither
My mass_input action is working by this way
def mass_input
#grade = Grade.find(#data['grade'])
#data = JSON.parse(params[:form_data])
Student.create(:rut => #data['mass_students'][1][0], :nombre => #data['mass_students'][1][1], :apellido => #data['mass_students'][1][2])
grade.students << student
respond_to do |format|
if student.save
format.html { redirect_to school_grade_path(grade.school,grade), notice: 'Alumno creado con éxito.' }
format.json { render :show, status: :created, location: student }
else
format.html { render :new }
format.json { render json: student.errors, status: :unprocessable_entity }
end
end
end
but I think is AWFUL, I must use my own create action
Thanks!!
Oh... From my point of view you are doing smth strange... The fast solution for your issue would be smth like this:
1) Rewrite before action in a new way:
before_action :set_grade
And method set_grade:
def set_grade
#grade = Grade.find(params[:grade_id].presence || #data['grade'])
end
2) Set method for student params
def student_params
data = JSON.parse(params[:form_data])['mass_students']
#Transform data to be student params. For ex:
data.map{|_key, info| {:rut => info[0], :nombre => info[1], :apellido => info[2]}}
end
3) Rewrite mass_input method
def mass_input
respond_to do |format|
if (#students = #grade.students.create(student_params).all?(&:persisted?)
#some actions when everything is great.
else
#some actions if not of them valid (maybe redirect & show info about not created students)
end
end
end
But you should definetly read more rails guides... http://guides.rubyonrails.org/
Sorry, I couldn't comment it. So I can just post a reply, it is not an complete answer though. In the student controller
Try to use
#student = #grade.students.new
or
#student = Student.new
#student.grade = #grade or #student.grade_id = params[:grade_id]
So when you do #student.save, you won't need to do the line below, and it will still work
#grade.students << #student
Ruby on rails has conventions you should follow to simplify lots of things. The first thing I see here is that in your def mass_input, you are using
Student.create(...)
The method create, as it says, creates an object but also saves it into database. So you should have new instead of create because new does not save it to database, just instantiates it:
#student = Student.new
...inside def mass_input, and by default the submit action in your view will take your object to the create method (if the object is new it goes to create, other way it goes to update, thanks to Rails). For this you could take a look at http://guides.rubyonrails.org/action_controller_overview.html
About the line #grade.students << #student, I assume you are intending to add the newly created student to his grade. See this example of usage of nested resources when trying to create, edit or destroy http://railscasts.com/episodes/139-nested-resources. In any case, nested resources implies this:
class Grade < ActiveRecord::Base
has_many :student
end
class Student < ActiveRecord::Base
belongs_to :grade
end
So, in your model Student you should have a column to store the Grade of that student. And then in your params you should receive the actual grade and store it in the grade_id inside your #student.
If something is not clear, I suggest you to take a look at the nested resources guide http://guides.rubyonrails.org/routing.html#nested-resources
As a commentary, << is used to add "things" to the end of an array, i.e. if you want to quickly store in an array some info you use:
array = []
Student.all.each do |s|
array << s.name
end
It will store in the array all the names of your students. Obviously there is a simpler way to do this by doing this:
Student.pluck(:name)
I am building a Rails app. And in my app, there are Projects where users can "Follow". When a user follows one of the pages, he/she will get updates if somebody uploads/creates a folder/file.
Below is the screenshot when somebody just created a new folder:
And below is the code for "Create" action in my Folder controller:
def create
#folder = current_user.folders.where(project_id: params[:project_id]).create(folder_params)
respond_to do |format|
if #folder.save
#folder.create_activity :create, owner: current_user, :params => {
:project_id => proc {|controller, project| #folder.project.id},
:project_name => proc {|controller, project| #folder.project.name},
}
format.html { redirect_to #folder.project, notice: 'Folder was successfully created.' }
format.json { render :show, status: :ok, location: #folder }
else
format.html { render :new }
format.json { render json: #folder.errors, status: :unprocessable_entity }
end
end
end
As you can see :project_id and :project_name are the parameters for the public_activity when a new folder being created.
And below is the screenshot on how this parameters value looks like in the database after they were saved:
QUESTION:
So my question is, how do i use this parameters values in my activities_controller?
Here is the code for my activities controller right now:
class ActivitiesController < ApplicationController
def index
#activities = PublicActivity::Activity.order("created_at desc").where(owner_id: current_user.following_users, owner_type: "User")
end
end
Instead of using "owner_id:", I want to use the "project_id" value from parameters column. So how can i do this?
Thank you very much in advanced! :)
The parameters field contains a simple yaml dump, so not really easy to search efficiently.
A simple solution would be to use LIKE operator, for instance
PublicActivity::Activity.where("parameters LIKE '%project_id: #{#project.id}%'")
You might want to consider to add custom fields instead.
Thanks for the answer, but I got a better solution than using the parameters value or custom field.
Here is how my activities_controller looks like right now:
class ActivitiesController < ApplicationController
def index
activity_table = PublicActivity::Activity.arel_table
# We want to view all activity of folders related to projects we are follwing
folder_ids = Folder.where(project_id: current_user.following_projects.pluck(:id)).pluck(:id)
# Generate query for all activity related to folders we care about
folders_query = activity_table[:trackable_type].eq('Folder').and(
activity_table[:trackable_id].in(folder_ids)
)
# Generate query for all users that we follow
users_query = activity_table[:owner_id].in(current_user.following_users.pluck(:id))
activity_query = folders_query.or(users_query)
#activities = PublicActivity::Activity.where(activity_query)
end
end
By using this way, I could easily combine the activities from the "Users" and also from the "Projects" that the user follows.
You can modify it to add any other activities such as from the "Comments" or "Voting".
Hope this will help other people out there that are using public_activity gem! :)
I currently have two views (new.html.erb and retirement_accounts_new.html.erb) in the Accounts both using the same create and update methods.
Here's how they're defined in the controller:
# GET /accounts/new
def new
#account = current_user.accounts.build
end
# GET /retirement/accounts/new
def retirement_accounts_new
#account = current_user.accounts.build
end
And here's the same create method they share:
def create
#account = current_user.accounts.build(account_params)
if #account.save
redirect_to accounts_path, notice: 'Account was successfully created.'
else
render action: 'new'
end
end
Is there a way to make that redirect_to accounts_path conditional based on which view is rendering the form?
I would like retirement_accounts_new on save/update to redirect_to retirement_accounts
It sounds like this might be a design issue. Are Accounts and RetirementAccounts significantly different? Will they share much of the same logic, but not all? If so, I think I would avoid using conditional logic in the controller and solve it using inheritance.
The idea here is that retirement_accounts would be considered a new resource in your routes file:
resources :retirement_accounts
Then you manually create a new controller for it (skip the rails generate... command). Save this file as app/controllers/retirement_accounts_controller.rb:
class RetirementAccountsController < AccountsController
end
Notice how it inherits from AccountsController instead of ApplicationController. Even in this empty state, RetirementAccountsController shares all of the logic of AccountsController, including the new and create methods, plus all of the view files to which they refer. To make the necessary modifications for the retirement accounts, you simply need to override the appropriate actions and views.
You can delete your retirement_accounts_new action, since it is identical to the new action. Move the view for retirement_accounts_new to app/views/retirement_accounts/new.html.erb, so that template will be rendered when new is called on the RetirementAccountsController.
As for the conditional create method, you can make a private method on both controllers that will determine where the post-create redirect should point:
class AccountsController < ApplicationController
# ...
def create
#account = current_user.accounts.build(account_params)
if #account.save
redirect_to post_create_redirect_path, notice: 'Account was successfully created.'
else
render action: 'new'
end
end
private
def post_create_redirect_path
accounts_path
end
end
class RetirementAccountsController < AccountsController
private
def post_create_redirect_path
retirement_accounts_path
end
end
If RetirementAccount < Account as a single table inheritance model then the thing you are asking would happen by default,
plan B would be to use explicit url_for in the redirect such as:
redirect_to url_for(controller: params[:controller], action: :show, id: #account.id), notice: 'Account was successfully created.'
Looking at the api doc this should work too:
redirect_to :action => "show", :id => #account.id,notice: 'Account was successfully created.'
Check out http://apidock.com/rails/ActionController/Base/redirect_to - there's probably an answer for you there somewhere :)
PS I have assumed that the the retirement account and account actions are in different controllers. If they're not in different controllers and not different model classes then you can put a hidden tag in the new form - but this is bad&ugly
Best solution is probably STI model and 2 separate resources for the 2 classes and everything will work out of the box. If this isn't an option, at least separate the controllers and make things clean that way, it's much better to reuse views then to reuse controllers
I'm having a very difficult rails problem and i thought to ask for some help. The situation is like this :
I'm using restful authentication for my User model. Now, user has a field named 'gold' that is a numeric value. There is another model named Book that has been created using scaffolding.
What i want to do is simple, yet i cannot see a way of doing it. I want to add some validation where if the user's gold is not, let's say 100, they cannot create a new book entry(from the scaffolding standard view).
Now the problem is that i need current_user information in order to validate this from my model. I need that in order to get the user id and therefore get their gold amount as well. I cannot find a good way (if any) to do that.
Another thought was doing that from a controller. However, the standard "if #book.save" block does not really allow me to insert my own error messages (inside scaffold create) :
if not User.has_the_needed_gold(current_user, 100)
flash[:goldError] = 'You do not have the needed gold to create this book.'
#end
respond_to do |format|
if #book.save
flash[:notice] = 'Book was successfully created.'
format.html { redirect_to(#book) }
format.xml { render :xml => #book, :status => :created, :location => #book }
else
format.html { render :action => "new" }
format.xml { render :xml => #book.errors, :status => :unprocessable_entity }
end
end
Now, i cannot output that message and abort the save of the new book as well. I've tried adding my own error to base, but it was cleared out(after save i guess). I'm quite confused with the situation and i've been searching around for a couple of hours with no results.
If anybody can help with that, please do so, you would spare me lots of trouble :)
Thanx for reading !
You could define a :user_gold virtual attribute for Book, set it in the controller where you have access to current_user and then incorporate that into your Book validation.
Look the user up when validating. It's likely the user lookup will have been cached by ActiveRecord, so it's not a performance hit to do so. Try something like this:
class Book
validate :check_gold
def check_gold
user = User.find(self.user_id)
self.errors.add(:user_id => "#{user.name} doesn't have enough gold!") if user.nil? or (user.gold < 100)
end
end
I have two tables:
Client(id,name,...)
Purchase(id,item,date,client_id,...)
They have their respective Model, with their validations. What I need is to create a new client with a new purchase, all into the create method of Client controller. Something like this:
def create
#client = Client.new(params[:client])
respond_to do |format|
if #client.save
# Add purchase
#sell = Purchase.new
#sell.client_id = #client.id
#sell.date = params[:date]
# Fill another fields
if #sell.save
# Do another stuff...
else
format.html { render :action => "new" }
format.xml { render :xml => #client.errors, :status => :unprocessable_entity }
end
flash[:notice] = 'You have a new client!'
format.html { redirect_to(:action => :show, :id => #evento.id) }
format.xml { render :xml => #client, :status => :created, :location => #client }
else
format.html { render :action => "new" }
format.xml { render :xml => #evento.client, :status => :unprocessable_entity }
end
end
end
In Purchase's model I have:
belongs_to :client
validates_format_of :date, :with => /^20[0-9]{2}[-][0-9]{2}[-][0-9]{2}$/, :message => 'not valid'
validates_presence_of :date
And there is my problem: how can I validate the date input, through validations into the model, from Client controller? And, how can I rollback the new client created when errors?
Yes, I can do the check as the very first instruction in the method, with a regular expression, but I think it's ugly. I feel like might exist a conventional method for doing this validation or even doing all the stuff in another way (i.e. calling create method for Purchase from Client controller).
Can you put me back in the right way?
Thank you in advance.
Take a look at the following page on working with associations.
Rails provides you with a bunch of handy methods on your objects.
Like the following:
Client.purchases.empty?
Client.purchases.size,
Client.purchases
Client.purchases<<(purchase)
Client.purchases.delete(purchase)
Client.purchases.find(purchases_id)
Client.purchases.find_all(conditions)
Client.purchases.build
Client.purchases.create
When using these methods, you're taking advantage of the validations on each of the models.
Hop into your Rails console and create a new client and try any of the above methods. You'll quickly learn how powerful they are and you'll be on your way in no time.
Edit: Here's a much better guide on Rails associations!
Depends a little on the situation, but you can use validates_associated to run the validations on associated objects. Then you can create the user (but don't save), create the purchase (but don't save) and try to save the user. If you've done it right the user will fail to save with a validation error on the associated object.