Question

I’ve got a process where user can activate a code that they’ve received: the activation process should do the following:

1. Add X credits to the user account (User.credits)
2. Create new creditlog item (just for history purposes)
3. Mark the code as activated, so that user can not activate it again.

I’m having a specific controller for this task. I created a method “code_activate”, that works. But it’s not ACID compliant, I believe. Should this be a method in some model (user?), or in a controller as I’ve done it? How would you implement it “the correct way”?

Here’s the code:

  def code_activate
    code = CreditCodes.find_by_code(params[:code])
    unless code
      render :json => { :success=>false, :message=>(t :codedoesnotexist)}
      return
    end

    if code.activated
      render :json => { :success=>false, :message=>(t :codealreadyactivated)}
      return
    end

    # Add credits to user
    current_user.credits += code.amount
    current_user.save

    # Save credit log record
    cl = current_user.creditlog.new
    cl.actionid = 1
    cl.amount = code.amount
    cl.save

    # Set code as activated
    code.activated = true
    code.save

    # Show success message
    render :json => { :success=>true, :message=>((t :creditsadded).gsub(/@AMOUNT@/, code.amount.to_s)) }, :status => :ok
  end

Answer 1

It’s business logic. It belongs into the model (CreditCode most likely)

You want to put this in a transaction to ensure that adding the amount and marking the code happens all or nothing.

Assume in your CreditCode you define a activate method like this:

def activate(user)
  transaction do
    # Add credits to user
    user.credits += code.amount
    user.save

    # Save credit log record
    cl = user.creditlog.new
    cl.actionid = 1
    cl.amount = amount
    cl.save

    # Set code as activated
    activated = true
    save  
  end
end