Rails - Jul 2006 - How can I intercept attribute calls?

Hi.

I have two types of fields in my database, e.g. "name" and
"name_ru".
First one is a user''s name in english and the second one is in russian.
I want to intercept calls like "c.name" and add "_ru" to it
if current
language is russian (I have my own Locale class like n Globalize).

So I want such thing:
--
Locale.set("en-US")
c.name = "Johny English" # will be stored in the "name"
column
Locale.set("ru-RU")
c.name = "Johny Russian" # will be stored in the "name_ru"
column
--

What ActiveRecord class and method should I overwrite to implement such 
thing?

Thanks.

P.S. I''ve googled but without any result. I''m reading
Globalize''s source
code atm and I hope to get something from here.

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On 7/2/06, Anton Kovalyov <anton@kovalyov.net>
wrote:
> Hi.
>
> I have two types of fields in my database, e.g. "name" and
"name_ru".
> First one is a user''s name in english and the second one is in
russian.
> I want to intercept calls like "c.name" and add "_ru"
to it if current
> language is russian (I have my own Locale class like n Globalize).
>
> So I want such thing:
> --
> Locale.set("en-US")
> c.name = "Johny English" # will be stored in the "name"
column
> Locale.set("ru-RU")
> c.name = "Johny Russian" # will be stored in the
"name_ru" column
> --
>
> What ActiveRecord class and method should I overwrite to implement such
> thing?
>
> Thanks.
>
> P.S. I''ve googled but without any result. I''m reading
Globalize''s source
> code atm and I hope to get something from here.
>
One way would be to do something like:
class Something < ActiveRecord::Base
  def name_before_type_cast
    if locale_is_russian
      read_attribute(:name_ru)
    else
      read_attribute(:name)
    end
  end
end

I''ll leave implementing the "locale_is_russian" method up to
you. Heh.

Wilson Bilkovich wrote:
> On 7/2/06, Anton Kovalyov <anton@kovalyov.net> wrote:
>> c.name = "Johny English" # will be stored in the
"name" column
>> code atm and I hope to get something from here.
>>
> 
> One way would be to do something like:
> class Something < ActiveRecord::Base
>   def name_before_type_cast
>     if locale_is_russian
>       read_attribute(:name_ru)
>     else
>       read_attribute(:name)
>     end
>   end
> end
> 
> I''ll leave implementing the "locale_is_russian" method
up to you. Heh.
I can''t do that because I don''t know exact name of an
attribute. It can
be "name" or "position", or "description".

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On 7/2/06, Anton Kovalyov <anton@kovalyov.net>
wrote:
> Wilson Bilkovich wrote:
> > On 7/2/06, Anton Kovalyov <anton@kovalyov.net> wrote:
> >> c.name = "Johny English" # will be stored in the
"name" column
> >> code atm and I hope to get something from here.
> >>
> >
> > One way would be to do something like:
> > class Something < ActiveRecord::Base
> >   def name_before_type_cast
> >     if locale_is_russian
> >       read_attribute(:name_ru)
> >     else
> >       read_attribute(:name)
> >     end
> >   end
> > end
> >
> > I''ll leave implementing the "locale_is_russian"
method up to you. Heh.
>
> I can''t do that because I don''t know exact name of an
attribute. It can
> be "name" or "position", or "description".
>
Is there a reason you can''t just define three methods?
def position_before_type_cast, description_before_type_cast, etc?

Are there only three, or are there numerous methods like this?

Wilson Bilkovich wrote:
> On 7/2/06, Anton Kovalyov <anton@kovalyov.net> wrote:
>> >       read_attribute(:name_ru)
>>
> Is there a reason you can''t just define three methods?
> def position_before_type_cast, description_before_type_cast, etc?
> 
> Are there only three, or are there numerous methods like this?
I don''t know what methods will I need. It depends on db scheme (as 
usual) and on translates method (as in Globalize: translates :name, 
:bla, :bla, ...).

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Anton Kovalyov wrote:
> Wilson Bilkovich wrote:
>> On 7/2/06, Anton Kovalyov <anton@kovalyov.net> wrote:
>>> >       read_attribute(:name_ru)
>>>
>> Is there a reason you can''t just define three methods?
>> def position_before_type_cast, description_before_type_cast, etc?
>> 
>> Are there only three, or are there numerous methods like this?
> 
> I don''t know what methods will I need. It depends on db scheme (as
> usual) and on translates method (as in Globalize: translates :name, 
> :bla, :bla, ...).
Actually, I already have a solution:

class ActiveRecord::Base
  def self.multilingual_field(fieldname)
    module_eval <<-end_eval
      def #{fieldname}
        send("#{fieldname}_\#{Locale.language.short_name}")
      end

      def #{fieldname}=(value)
        send("#{fieldname}_\#{Locale.language.short_name}=",value)
      end
    end_eval
  end
end


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On 7/3/06, Anton Kovalyov <anton@kovalyov.net>
wrote:
> Anton Kovalyov wrote:
> > Wilson Bilkovich wrote:
> >> On 7/2/06, Anton Kovalyov <anton@kovalyov.net> wrote:
> >>> >       read_attribute(:name_ru)
> >>>
> >> Is there a reason you can''t just define three methods?
> >> def position_before_type_cast, description_before_type_cast, etc?
> >>
> >> Are there only three, or are there numerous methods like this?
> >
> > I don''t know what methods will I need. It depends on db
scheme (as
> > usual) and on translates method (as in Globalize: translates :name,
> > :bla, :bla, ...).
>
> Actually, I already have a solution:
>
> class ActiveRecord::Base
>   def self.multilingual_field(fieldname)
>     module_eval <<-end_eval
>       def #{fieldname}
>         send("#{fieldname}_\#{Locale.language.short_name}")
>       end
>
>       def #{fieldname}=(value)
>        
send("#{fieldname}_\#{Locale.language.short_name}=",value)
>       end
>     end_eval
>   end
> end
>
>
Cool. Be warned that the built-in Rails form helpers don''t call the
attribute directly, though.
They call attribute_before_type_cast.

text_field :something, :name will still show the ''raw'' column
value,
unless you implement the before_type_cast methods.

Wilson Bilkovich wrote:
> 
> Cool. Be warned that the built-in Rails form helpers don''t call
the
> attribute directly, though.
> They call attribute_before_type_cast.
> 
> text_field :something, :name will still show the ''raw''
column value,
> unless you implement the before_type_cast methods.
Wow, I didn''t know about this. Thanks a lot.

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