Rails - Mar 2009 - Preventing a submitted hash from ActiveRecord DB store

Hi all,

I have a multi model form (Project with many tasks) and I want to
prevent a task from being saved to the DB if it is empty ie. if there
is no i/p for that task from the user. I tried the following

class Task < ActiveRecord::Base

before_save :check_if_empty
...

def check_if_empty
    self.destroy if description.blank?
end

but i get this

TypeError in ProjectsController#create
can''t modify frozen hash

Is there a way to let ActiveRecord know not to save a record (which is
a frozen hash in this case) to the DB?
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validates_length_of :description, :minimum => 1

On Mar 17, 6:58 am, Ram
<yourstruly.vi...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Hi all,
>
> I have a multi model form (Project with many tasks) and I want to
> prevent a task from being saved to the DB if it is empty ie. if there
> is no i/p for that task from the user. I tried the following
>
> class Task < ActiveRecord::Base
>
> before_save :check_if_empty
> ...
>
> def check_if_empty
>     self.destroy if description.blank?
> end
>
> but i get this
>
> TypeError in ProjectsController#create
> can''t modify frozen hash
>
> Is there a way to let ActiveRecord know not to save a record (which is
> a frozen hash in this case) to the DB?
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On Mar 17, 5:58 am, Ram
<yourstruly.vi...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Hi all,
>
> I have a multi model form (Project with many tasks) and I want to
> prevent a task from being saved to the DB if it is empty ie. if there
> is no i/p for that task from the user. I tried the following
>
If you don''t want the save to happen then you should return false from
your before_save.

Fred
> class Task < ActiveRecord::Base
>
> before_save :check_if_empty
> ...
>
> def check_if_empty
>     self.destroy if description.blank?
> end
>
> but i get this
>
> TypeError in ProjectsController#create
> can''t modify frozen hash
>
> Is there a way to let ActiveRecord know not to save a record (which is
> a frozen hash in this case) to the DB?
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@Wolas!,

I figured a validation will do the trick but knew something simpler
had to be there.

@Fred,

Dint count on it being SO simple!! :D <bangin head on wall>

Thanks guys. returning "false" did the trick.

On Mar 17, 2:22 pm, Frederick Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> On Mar 17, 5:58 am, Ram
<yourstruly.vi...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> > Hi all,
>
> > I have a multi model form (Project with many tasks) and I want to
> > prevent a task from being saved to the DB if it is empty ie. if there
> > is no i/p for that task from the user. I tried the following
>
> If you don''t want the save to happen then you should return false
from
> your before_save.
>
> Fred
>
> > class Task < ActiveRecord::Base
>
> > before_save :check_if_empty
> > ...
>
> > def check_if_empty
> >     self.destroy if description.blank?
> > end
>
> > but i get this
>
> > TypeError in ProjectsController#create
> > can''t modify frozen hash
>
> > Is there a way to let ActiveRecord know not to save a record (which is
> > a frozen hash in this case) to the DB?
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Hi Fred,

I had Project has_many Tasks and i had the following before_save
callback on Task

  def capitalis
    if (name.blank?)
      false
    else
      self.name = name.capitalize
    end
  end

Now I need to make Project and Task share a HABTM relationship. I
started experimenting with it after establishing the associations.
Created a new Project, with some tasks in it and left on task blank. I
got an ActiveRecord::RecordNotSaved error for the blank Task.
Now I understand it is because of the false return in the callback.
And this also cancels all following callbacks and association
callbacks (?). So although the valid Tasks and the Project itself DO
get saved to the DB, I get this error.
Is it neat enough to rescue from this specific error in the controller
and ignore it? Seems slightly hacky.. so, is there a nicer way to
handle this?
Thanks..


On Mar 17, 2:43 pm, Ram
<yourstruly.vi...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> @Wolas!,
>
> I figured a validation will do the trick but knew something simpler
> had to be there.
>
> @Fred,
>
> Dint count on it being SO simple!! :D <bangin head on wall>
>
> Thanks guys. returning "false" did the trick.
>
> On Mar 17, 2:22 pm, Frederick Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> wrote:
>
> > On Mar 17, 5:58 am, Ram
<yourstruly.vi...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> > > Hi all,
>
> > > I have a multi model form (Project with many tasks) and I want to
> > > prevent a task from being saved to the DB if it is empty ie. if
there
> > > is no i/p for that task from the user. I tried the following
>
> > If you don''t want the save to happen then you should return
false from
> > your before_save.
>
> > Fred
>
> > > class Task < ActiveRecord::Base
>
> > > before_save :check_if_empty
> > > ...
>
> > > def check_if_empty
> > >     self.destroy if description.blank?
> > > end
>
> > > but i get this
>
> > > TypeError in ProjectsController#create
> > > can''t modify frozen hash
>
> > > Is there a way to let ActiveRecord know not to save a record
(which is
> > > a frozen hash in this case) to the DB?
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