Rails - Feb 2006 - Design question - where to store constants?

Let''s say I create a "ticket system" that has a support
ticket with a
status attached to it.  (Say, OPEN or CLOSED for now, but more later)

The status -could- be another table in the database listing status 
types, but I think that''s unnecessarily complex and overly flexible for
this.  (opinions on this point would be interesting)

Another alternative would be to define the statuses as a constant within 
the application:

ticket_status = ["Open", "Closed"]

Where is this constant declaration best suited?  At the App level in the 
CONFIG[]?  Or in the model for the ticket?  The controller for the 
ticket?  It seems to be a model thing.

   Jake

-- 
Posted via http://www.ruby-forum.com/.

Jake Janovetz wrote:
> Let''s say I create a "ticket system" that has a support
ticket with a
> status attached to it.  (Say, OPEN or CLOSED for now, but more later)
> 
> The status -could- be another table in the database listing status 
> types, but I think that''s unnecessarily complex and overly
flexible for
> this.  (opinions on this point would be interesting)
> 
> Another alternative would be to define the statuses as a constant within 
> the application:
> 
> ticket_status = ["Open", "Closed"]
> 
> Where is this constant declaration best suited?  At the App level in the 
> CONFIG[]?  Or in the model for the ticket?  The controller for the 
> ticket?  It seems to be a model thing.
> 
>    Jake
You could define it in environment.rb:
TICKET_STATUS = ["Open", "Closed"]

Or in the model, it doesnt really matter.


-- 
Posted via http://www.ruby-forum.com/.

Hi --

On Sun, 12 Feb 2006, Jake Janovetz wrote:
> Let''s say I create a "ticket system" that has a support
ticket with a
> status attached to it.  (Say, OPEN or CLOSED for now, but more later)
>
> The status -could- be another table in the database listing status
> types, but I think that''s unnecessarily complex and overly
flexible for
> this.  (opinions on this point would be interesting)
>
> Another alternative would be to define the statuses as a constant within
> the application:
>
> ticket_status = ["Open", "Closed"]
That''s not a constant -- do you mean TICKET_STATUSES or something?
(Actually if you have a Ticket class you would probably want a
constant just called STATUSES.)
> Where is this constant declaration best suited?  At the App level in the
> CONFIG[]?  Or in the model for the ticket?  The controller for the
> ticket?  It seems to be a model thing.
I think it''s a model thing.  Basically, you''re trying *not* to
have to
type the list of statuses over again if it''s used in multiple methods.
So it''s just an abstraction one level up:

   class Ticket < ActiveRecord::Base

     STATUSES = %w{ Open Closed }  # or whatever :-)

     def check_status
       STATUSES.include?(status)
     end

     def something_else
       # do something else with STATUSES
     end
   end

No need to stash it further away than this.  It makes sense, too, that
the statuses list would be a class-level resource of Ticket.


David

-- 
David A. Black (dblack@wobblini.net)
Ruby Power and Light (http://www.rubypowerandlight.com)

"Ruby for Rails" chapters now available
from Manning Early Access Program! http://www.manning.com/books/black

First of all for this case it''d probably be best just to make it a
boolean.  It''ll lead to natural code, like

if ticket.open?
  ...

If you really want to go for string statuses though, David''s code
looks pretty good.  I''d do something like,

class Ticket < ActiveRecord::Base
  Open= ''open''
  Closed = ''closed''
  Statuses = [Open, Closed]

  def status_is?(s)
    status == s
  end
end

This would lead to the reasonably natural code:
if ticket.status_is?(Ticket::Open)
  ...

You can then also create an open? method, which just checks the status
with a default val (open classes make it more fun to write mailing
list posts :)

class Ticket < ActiveRecord::Base
  def open?
    status_is?(Open)
  end
end

The very last thing is that you will want to write a validation:

class Ticket < ActiveRecord::Base
  def validate
    unless status and Statuses.include?(status)
      errors.add(:status, ''must be one of the following: '' +
Statuses.join('', '')
    end
  end
end

Anyway, imo this is all a pretty ugly to solution when it can be
solved by simply making this field a boolean.

Pat



On 2/12/06, Jake Janovetz <jake@janovetz.com>
wrote:
> Let''s say I create a "ticket system" that has a support
ticket with a
> status attached to it.  (Say, OPEN or CLOSED for now, but more later)
>
> The status -could- be another table in the database listing status
> types, but I think that''s unnecessarily complex and overly
flexible for
> this.  (opinions on this point would be interesting)
>
> Another alternative would be to define the statuses as a constant within
> the application:
>
> ticket_status = ["Open", "Closed"]
>
> Where is this constant declaration best suited?  At the App level in the
> CONFIG[]?  Or in the model for the ticket?  The controller for the
> ticket?  It seems to be a model thing.
>
>    Jake
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

On Sun, 2006-02-12 at 18:50 -0700, Pat Maddox wrote:
> First of all for this case it''d probably be best just to make it a
> boolean.  It''ll lead to natural code, like
> 
> if ticket.open?
>   ...
> 
----
OK - I asked the other day and didn''t get a bite so since you mentioned
it...

I am using a boolean...

Accepted and it stores either a 0 or 1 in postgres which is good.

It displays ''true'' or ''false'' on screen and
I would much rather have it
display ''yes'' or ''no''

How do I change the display of that boolean? Is there a helper or do I
have to write it?  Can I write it so that I can refer to it again and
again with other booleans?

Craig

Craig White wrote:
> On Sun, 2006-02-12 at 18:50 -0700, Pat Maddox wrote:
>> First of all for this case it''d probably be best just to make
it a
>> boolean.  It''ll lead to natural code, like
>> 
>> if ticket.open?
>>   ...
Well, if open/closed is all I wanted to deal with, yes.  We''ll see.
> 
> It displays ''true'' or ''false'' on screen
and I would much rather have it
> display ''yes'' or ''no''
> 
> How do I change the display of that boolean? Is there a helper or do I
> have to write it?  Can I write it so that I can refer to it again and
> again with other booleans?
The simplest way would be:  ( ticket.open? ? ''yes'' :
''no'' )


-- 
Posted via http://www.ruby-forum.com/.

On Mon, 2006-02-13 at 03:25 +0100, Jake Janovetz wrote:
> Craig White wrote:
> > On Sun, 2006-02-12 at 18:50 -0700, Pat Maddox wrote:
> >> First of all for this case it''d probably be best just to
make it a
> >> boolean.  It''ll lead to natural code, like
> >> 
> >> if ticket.open?
> >>   ...
> 
> Well, if open/closed is all I wanted to deal with, yes.  We''ll
see.
> 
> > 
> > It displays ''true'' or ''false'' on
screen and I would much rather have it
> > display ''yes'' or ''no''
> > 
> > How do I change the display of that boolean? Is there a helper or do I
> > have to write it?  Can I write it so that I can refer to it again and
> > again with other booleans?
> 
> The simplest way would be:  ( ticket.open? ? ''yes'' :
''no'' )
----
works for me - thanks

Craig