Rails - Jul 2006 - Calling a method each time an ActiveRecord Object is accessd

Hi,

I know that it is possible to execute code each time data is saved into 
a model by using the +validate+ method.

However, is there also a way to execute code each time the data is 
accessed, not just when it is changed?

Bye,
Winsmith

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Daniel Jilg wrote:
> I know that it is possible to execute code each time data is saved into 
> a model by using the +validate+ method.
> 
> However, is there also a way to execute code each time the data is 
> accessed, not just when it is changed?
You can create your own accessor methods for a model''s attributes and 
put any code you want in there. The attributes hash holds the model''s 
attributes so you can get to it from the accessor.

def phone
  self.format_phone_number(attributes[:phone])
end

--
Josh Susser
http://blog.hasmanythrough.com

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On 7/7/06, Josh Susser <josh@hasmanythrough.com>
wrote:
> Daniel Jilg wrote:
> > I know that it is possible to execute code each time data is saved
into
> > a model by using the +validate+ method.
> >
> > However, is there also a way to execute code each time the data is
> > accessed, not just when it is changed?
>
> You can create your own accessor methods for a model''s attributes
and
> put any code you want in there. The attributes hash holds the
model''s
> attributes so you can get to it from the accessor.
>
> def phone
>   self.format_phone_number(attributes[:phone])
> end
There are also the ActiveRecord::Callbacks that might do what you
need; specifically the after_find and after_initialize might work
nicely. They have some weird caveats so check out the docs before
trying them.

http://api.rubyonrails.com/classes/ActiveRecord/Callbacks.html

Cheers,
Chuck Vose

I got it! Thanks a lot you two!

Josh, btw, thanks a lot for the excellent has_many :through explanation 
in your blog!

bye,
Daniel

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Quick correction for later viewers: It appears that the attributes hash 
isn''t created with :symbols as implied above. So above example would be

def phone
    self.format_phone_number(attributes["phone"])
end

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