Rails - May 2010 - How to add an after_save callback on runtime on a particular instance

class User < AR
end

user = User.new


Let''s say that I have a user instance with me. After this record is
saved I want an after_save callback which would print the id of the
record.
The only catch is that I am not allowed to change the User class. How
can I accomplish my goal? Is that even possible to add an after_save
callback on a particular instance object. Any metaprogramming hack.
I''m sure ruby does provide some tool.


This would be a trivial issue if I were allowed to change the User
class but I am not.

-- 
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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

On 12 May 2010 03:15, Nadal
<node.js99-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> class User < AR
> end
>
> user = User.new
>
>
> Let''s say that I have a user instance with me. After this record
is
> saved I want an after_save callback which would print the id of the
> record.
> The only catch is that I am not allowed to change the User class. How
> can I accomplish my goal? Is that even possible to add an after_save
> callback on a particular instance object. Any metaprogramming hack.
> I''m sure ruby does provide some tool.
>
>
> This would be a trivial issue if I were allowed to change the User
> class but I am not.
What do you mean by ''not allowed to change the User class''? 
Do you
mean that you are not allowed to change the file user.rb?  If so that
is not a problem as you can modify or extend the class in another
loaded file merely by providing class User < ... and providing new or
modified methods there.

Colin
>
> --
> 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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.
>
>
-- 
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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

On May 12, 3:15 am, Nadal
<node.j...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> class User < AR
> end
>
> user = User.new
>
> Let''s say that I have a user instance with me. After this record
is
> saved I want an after_save callback which would print the id of the
> record.
> The only catch is that I am not allowed to change the User class. How
> can I accomplish my goal? Is that even possible to add an after_save
> callback on a particular instance object. Any metaprogramming hack.
> I''m sure ruby does provide some tool.
well on top of what Colin says you can do

def user.some_method

end

or user.extend SomeModule

I think both will prevent you from marshalling the object and I seem
to remember that in MRI both will cause ruby to dump it''s cache of
method names to implementations

Fred
>
> This would be a trivial issue if I were allowed to change the User
> class but I am not.
>
> --
> 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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com.
> For more options, visit this group
athttp://groups.google.com/group/rubyonrails-talk?hl=en.
-- 
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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.