Rails - May 2006 - how to make field in model immutable after create

Hello everyone!

I want to have login field in User model which is set only once (on
create), and then it should fail validation if the value is changed.
How can I do this? I dig around for validation and tried

def after_validation_on_update
  unless User.find_by_login(:login)
    errors.add(:login, "is immutable. You can''t change it")
  end
end

in model, but somewhat it doesn''t work. Any hints on how can I make
field immutable after create?

Peace,
olegf

I''m almost positive there''s a better way, but you could try
something
like this in the validate method of your model.

def validate

    errors.add( :login, "Can''t change your login details") if
self.login != User.find(self.id).login

end




On 5/8/06, Oleg Frolov <leopardus.vulgaris@gmail.com>
wrote:
> Hello everyone!
>
> I want to have login field in User model which is set only once (on
> create), and then it should fail validation if the value is changed.
> How can I do this? I dig around for validation and tried
>
> def after_validation_on_update
>   unless User.find_by_login(:login)
>     errors.add(:login, "is immutable. You can''t change
it")
>   end
> end
>
> in model, but somewhat it doesn''t work. Any hints on how can I
make
> field immutable after create?
>
> Peace,
> olegf
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Sorry there should be another line in that method

def validate
  if not self.new_record?
    errors.add( :login, "Can''t change your login details") if
                      self.login != User.find(self.id).login
  end
end


On 5/8/06, Liquid <has.sox@gmail.com> wrote:
> I''m almost positive there''s a better way, but you could
try something
> like this in the validate method of your model.
>
> def validate
>
>     errors.add( :login, "Can''t change your login
details") if
> self.login != User.find(self.id).login
>
> end
>
>
>
>
> On 5/8/06, Oleg Frolov <leopardus.vulgaris@gmail.com> wrote:
> > Hello everyone!
> >
> > I want to have login field in User model which is set only once (on
> > create), and then it should fail validation if the value is changed.
> > How can I do this? I dig around for validation and tried
> >
> > def after_validation_on_update
> >   unless User.find_by_login(:login)
> >     errors.add(:login, "is immutable. You can''t change
it")
> >   end
> > end
> >
> > in model, but somewhat it doesn''t work. Any hints on how can
I make
> > field immutable after create?
> >
> > Peace,
> > olegf
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> >
>

Can you just override the default setter that active records creates in your
model and throw an execption if it gets called?
 
----------------------------------------------------------------------------------------------------
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it''s ever done in a PC.

My Digital Life - http://scottwalter.com/blog
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----- Original Message ----
From: Oleg Frolov <leopardus.vulgaris@gmail.com>
To: rails@lists.rubyonrails.org
Sent: Monday, May 8, 2006 12:53:13 AM
Subject: [Rails] how to make field in model immutable after create

Hello everyone!

I want to have login field in User model which is set only once (on
create), and then it should fail validation if the value is changed.
How can I do this? I dig around for validation and tried

def after_validation_on_update
  unless User.find_by_login(:login)
    errors.add(:login, "is immutable. You can''t change it")
  end
end

in model, but somewhat it doesn''t work. Any hints on how can I make
field immutable after create?

Peace,
olegf
_______________________________________________
Rails mailing list
Rails@lists.rubyonrails.org
http://lists.rubyonrails.org/mailman/listinfo/rails



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Yep, just do:

class User < ActiveRecord::Base
  def login=(value)
    # Either ignore the call, add an error, or raise an exception
  end
end

On 5/9/06, Scott Walter <tx_scottwalter@yahoo.com>
wrote:
>
> Can you just override the default setter that active records creates in
your
> model and throw an execption if it gets called?
>
----------------------------------------------------------------------------------------------------

If you make it so that the setter method throws an exception/stops the call,
how do you set the login when the record is first created?


On 5/8/06, Jonathan Viney <jonathan.viney@gmail.com>
wrote:
>
> Yep, just do:
>
> class User < ActiveRecord::Base
>   def login=(value)
>     # Either ignore the call, add an error, or raise an exception
>   end
> end
>
> On 5/9/06, Scott Walter <tx_scottwalter@yahoo.com> wrote:
> >
> > Can you just override the default setter that active records creates
in
> your
> > model and throw an execption if it gets called?
> >
>
----------------------------------------------------------------------------------------------------
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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Something along the lines of...

def login= (value)
  if new_record?
    self[:login] = value
  else
    raise "You can''t change login"
  end
end

On 5/8/06, Liquid <has.sox@gmail.com> wrote:
> If you make it so that the setter method throws an exception/stops the
call,
> how do you set the login when the record is first created?
>
>
>
> On 5/8/06, Jonathan Viney <jonathan.viney@gmail.com> wrote:
> > Yep, just do:
> >
> > class User < ActiveRecord::Base
> >   def login=(value)
> >     # Either ignore the call, add an error, or raise an exception
> >   end
> > end
> >
> > On 5/9/06, Scott Walter < tx_scottwalter@yahoo.com> wrote:
> > >
> > > Can you just override the default setter that active records
creates in
> your
> > > model and throw an execption if it gets called?
> > >
>
----------------------------------------------------------------------------------------------------
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> >
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>