Rails - Oct 2007 - Best approach - letting users put their own temp. fields to see diff

Hey everyone!

I need some input on the best approach. I have a model Property that
has some fields (price, down payment rate), then methods in
property.rb that compute derived information (down payment amount)
based on what the users input. Sounds simple enough.

I. PROBLEM
Here''s where I need help: I want to make a "property
calculator" of
sorts that takes a property, and allows users to input their numbers
without overwriting the current property to see how the outcome
(value) of the property/investment changes based on those numbers.

For example... the property saved in the database has a price of
100,000.00 and down payment rate of 10%. Derived information from
that: down payment is 10,000.00. In the property calculator, I want to
input 20% to see how the derived information will change, but I don''t
want to save this into the property.

II. THE WAY I THOUGHT OF DOING IT
I know how to do it, but it''s very tedious, and I know that once
something becomes tedious in Rails and I''m probably approaching things
wrong.

I was thinking of putting options in each of the methods in the
Property class.  For example,

def down_payment(options={})
  options.stringify_keys!
  dpr = options[''down_payment_rate''].to_f || down_payment_rate
  price * dpr
end

This sounds nice and simple enough at the start but I have many of
these derived methods and putting this options thing in all of them
would be a hassle.

How do you suggest I approach this?

Thank you
-- 
Ramon Tayag

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Ramon Miguel M. Tayag wrote:
> Hey everyone!
> 
> I need some input on the best approach. I have a model Property that
> has some fields (price, down payment rate), then methods in
> property.rb that compute derived information (down payment amount)
> based on what the users input. Sounds simple enough.
> 
> I. PROBLEM
> Here''s where I need help: I want to make a "property
calculator" of
> sorts that takes a property, and allows users to input their numbers
> without overwriting the current property to see how the outcome
> (value) of the property/investment changes based on those numbers.
> 
> For example... the property saved in the database has a price of
> 100,000.00 and down payment rate of 10%. Derived information from
> that: down payment is 10,000.00. In the property calculator, I want to
> input 20% to see how the derived information will change, but I
don''t
> want to save this into the property.
> 
> II. THE WAY I THOUGHT OF DOING IT
> I know how to do it, but it''s very tedious, and I know that once
> something becomes tedious in Rails and I''m probably approaching
things
> wrong.
> 
> I was thinking of putting options in each of the methods in the
> Property class.  For example,
> 
> def down_payment(options={})
>   options.stringify_keys!
>   dpr = options[''down_payment_rate''].to_f ||
down_payment_rate
>   price * dpr
> end
> 
> This sounds nice and simple enough at the start but I have many of
> these derived methods and putting this options thing in all of them
> would be a hassle.
> 
> How do you suggest I approach this?
> 
> Thank you
Why would anything be saved back to the database in the first place? Or 
are you doing the math in your app rather than doing it in JavaScript?


-- 
Michael Wang

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

The math will be done in the app.. :)  I don''t mean to save the fields
into the database if it''s just the calculator I''m accessing.

On 10/8/07, Michael Wang
<rails-user-JtyympAsP2K7zZZRDBGcUA@public.gmane.org>
wrote:
>
> Why would anything be saved back to the database in the first place? Or
> are you doing the math in your app rather than doing it in JavaScript?
>
>
> --
> Michael Wang
-- 
Ramon Tayag

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Just use the original Property to put the initial view together, then 
when changes come in make a new Property from the params but don''t save
it, just use it to put the requested view together.

def update
  if params[:commit] == ''Preview Changes''
    @property = Property.new(params[:property])
    render :action => ''edit''
  else
    # update the saved property
    @property = Property.find(params[:id])
    if @property.update_attributes(params[:property])
      flash[:notice] = ''Property was successfully updated.''
      redirect_to :action => ''show'', :id => @property
    else
      render :action => ''edit''
    end # if
  end # if
end # update

...or something like that (maybe your edit action is called
"calculator"
and your update action is called "calculate"). As long as you
don''t call
save or update_attributes on the property, it will be used in the view 
but won''t get saved to the database. If you don''t want to give
them the
option of saving the changes, make it a separate method that just does 
the first part.
-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---