Fetching a sum for the current_user, accessible through a js.erb partial

Question

I have a model Expense.rb, in which a user has many. New expenses can be added through an ajax form and thus I have the appropriate files setup (create.js.erb, destroy.js.erb.. etc)

Currently when a new expense is submitted via the remote form, an amount sum is also updated in the create.js.erb, which in my Expense model looks like this:

def total_value
    Expense.sum(:amount)
end

create.js.erb:

$('#total').html('$<%= number_with_delimiter(@expense.total_value) %>');

The problem is this sums all expenses from the database whereas I need to just find for the current_user (which I know is not accessible from the model).

Inside my controller, on the index action I'm doing it like so:

@expenses = current_user.expenses
    @total_value = @expenses.sum(:amount)

which means I can fetch it for the current_user in my index view by just doing: <%= number_with_delimiter(@total_value) %>

but as for the create action:

def create
    @expense = Expense.new(secure_params)
    @expense.user = User.find(current_user.id)
    @expense.save
    respond_to do |format|
      format.html { redirect_to index_expense_path }
      format.js
    end
  end

I'm not sure how to go about passing the current_user to total_value in the model in order to sum just for the current_user id in total_value which is used in the create js.erb.

Refer http://stackoverflow.com/questions/2513383/access-current-user-in-model — Rajesh Omanakuttan, Apr 04 '14 at 08:25
@RajeshCO I'm trying to identify the correct MVC way to do this, I saw that link before, not sure if any of the answers inside are the correct way to do this. — Jon Girard, Apr 04 '14 at 08:28

score 5 · Accepted Answer · answered Apr 04 '14 at 08:29

Expense.sum(:amount) takes all the expense records out.

Changing

def total_value
    Expense.sum(:amount)
end

to:

def self.total_value
    sum(:amount)
end

would call self, so doing

current_user.expenses.total_value

should work, and if you do Expense.total_value will still keep working.

score 0 · Answer 2 · answered Apr 04 '14 at 08:26

0

The problem is this sums all expenses from the database whereas I need to just find for the current_user (which I know is not accessible from the model).

Perhaps you could use a scope & pass the user id to it:

#app/controllers/expenses_controller.rb
def total_votes
   Expense.user(current_user).sum(:amount)
end

#app/models/expense.rb
Class Expense < ActiveRecord::Base
    scope :user, ->(user) { where(user_id: user.id) }
end

answered Apr 04 '14 at 08:26

Richard Peck

76,116
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Thank you for your answer. Ended up not needing to use scope. – Jon Girard Apr 04 '14 at 08:34

score 0 · Answer 3 · answered Apr 04 '14 at 08:31

0

Don't you need a total_expenses method in your User model:

Class User

  has_many :expenses

  def total_expenses
    expenses.sum(:amount)
  end
end

Then you can just call

current_user.total_expenses

answered Apr 04 '14 at 08:31

Chris Lewis

1,315
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Fetching a sum for the current_user, accessible through a js.erb partial

3 Answers3