Rails - Sep 2008 - Activerecord: use attributes methods instead of attrs var

This is the case: when you call save() on an activerecord::base object
it goes through all the attrs[:] and saves them. But I have a lot of
attributes overriden.
For example:

class Tester
  def name
    write_attribute(:name, ''This is just a silly example!'')
    read_attribute(:name)
  end
end

t = Tester.new
t.save

But when I do save() it doesn''t get saved to the database if I
haven''t
called the name() method.

When I add a validation, the method somewhere gets called and it is
added to the attrs instance variable.

Is there a way, without adding validations for every attribute, to call
the attribute methods before save?

I thought about using a before_save filter, but maybe someone would new
a better/other way.

I''m just curious if it''s possible. Maybe I''m on the
wrong track and
there may be better ways to override the attribute getters?

Thanks in advance!
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On Mon, Sep 22, 2008 at 6:05 PM, Leon Bogaert <
rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
>
> This is the case: when you call save() on an activerecord::base object
> it goes through all the attrs[:] and saves them. But I have a lot of
> attributes overriden.
> For example:
>
> class Tester
>  def name
>    write_attribute(:name, ''This is just a silly
example!'')
>    read_attribute(:name)
>  end
> end
>
> t = Tester.new
> t.save
>
> But when I do save() it doesn''t get saved to the database if I
haven''t
> called the name() method.
>
> When I add a validation, the method somewhere gets called and it is
> added to the attrs instance variable.
>
> Is there a way, without adding validations for every attribute, to call
> the attribute methods before save?
>
> I thought about using a before_save filter, but maybe someone would new
> a better/other way.
>
> I''m just curious if it''s possible. Maybe I''m on
the wrong track and
> there may be better ways to override the attribute getters?
>
You''re essentially trying to set default values for your attributes,
right?
If so, I would use the #after_initialize callback, which AR calls when a new
instance of the class is created.

  class Tester < ActiveRecord::Base
    def after_initialize
        self.name ||= ''Default name''
    end
  end

Brandon
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I would recommend the before_create callback.
it seems you do not need to overwrite the the attributes everytime you
update it,
and before_create work only for new records.

after_initialize has performance issue
and overwrite the default getter may cause side effects.

hope that helps.

Regards,

Peng Zuo

On Tue, Sep 23, 2008 at 8:10 AM, Brandon Keepers
<brandon-NYlJC1mBhkRg9hUCZPvPmw@public.gmane.org>
wrote:
> On Mon, Sep 22, 2008 at 6:05 PM, Leon Bogaert
> <rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
>>
>> This is the case: when you call save() on an activerecord::base object
>> it goes through all the attrs[:] and saves them. But I have a lot of
>> attributes overriden.
>> For example:
>>
>> class Tester
>>  def name
>>    write_attribute(:name, ''This is just a silly
example!'')
>>    read_attribute(:name)
>>  end
>> end
>>
>> t = Tester.new
>> t.save
>>
>> But when I do save() it doesn''t get saved to the database if I
haven''t
>> called the name() method.
>>
>> When I add a validation, the method somewhere gets called and it is
>> added to the attrs instance variable.
>>
>> Is there a way, without adding validations for every attribute, to call
>> the attribute methods before save?
>>
>> I thought about using a before_save filter, but maybe someone would new
>> a better/other way.
>>
>> I''m just curious if it''s possible. Maybe I''m
on the wrong track and
>> there may be better ways to override the attribute getters?
>
> You''re essentially trying to set default values for your
attributes, right?
> If so, I would use the #after_initialize callback, which AR calls when a
new
> instance of the class is created.
>
>   class Tester < ActiveRecord::Base
>     def after_initialize
>         self.name ||= ''Default name''
>     end
>   end
>
> Brandon
> --
>
--------------------------------------------------------------------------------
> Sessions by Collective Idea: Ruby on Rails training in a vacation setting
> http://sessions.collectiveidea.com
>
> >
>


-- 

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