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Grary

2010-Apr-01 12:51 UTC

Newbie seeking advice on DRYing up my model validations...

Hi,

Despite close reading of Matz''s Ruby book and Agile Web Dev. w. Rails,
I can''t  figure out how to tackle the challenge of sharing validation
code across models with attributes in common.

In each of my models I''d like to validate the shared attributes with a
custom validator that includes Rails ActiveRecord::Validations class
methods and some of my own validations. My problem is 1) I don''t know
how to pass attribute references to my special method and 2) (mundane)
I can''t successfully call any ActiveRecord::Validations class methods
from within my custom method.

A bit of garbage here, I know, but any thoughts? Is this kind of
problem handled by use of certain gems?

Thanks,

Grar

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Lasse Bunk

2010-Apr-01 13:41 UTC

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Re: Newbie seeking advice on DRYing up my model validations...

Hi Grar,

If you have a User model where you want to use some shared validations, you
could create a module like this – in lib/my_email_validations.rb:

  module MyEmailValidations
    def self.included(base)
      base.validates_presence_of :email
      base.validates_length_of :email, :minimum => 6
      base.validate :email_must_be_from_valid_provider
    end

    # example of a custom validator
    def email_must_be_from_valid_provider
      errors.add :email, "must be from a valid provider" if
        email !~ /@gmail.com$/
    end
  end

and in your User model, include them like this:

  class User < ActiveRecord::Base
    include MyEmailValidations
  end

Does this solve your problem?

/Lasse

2010/4/1 Grary <grary.stimon-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Hi,
>
> Despite close reading of Matz''s Ruby book and Agile Web Dev. w.
Rails,
> I can''t  figure out how to tackle the challenge of sharing
validation
> code across models with attributes in common.
>
> In each of my models I''d like to validate the shared attributes
with a
> custom validator that includes Rails ActiveRecord::Validations class
> methods and some of my own validations. My problem is 1) I don''t
know
> how to pass attribute references to my special method and 2) (mundane)
> I can''t successfully call any ActiveRecord::Validations class
methods
> from within my custom method.
>
> A bit of garbage here, I know, but any thoughts? Is this kind of
> problem handled by use of certain gems?
>
> Thanks,
>
> Grar
>
> --
> You received this message because you are subscribed to the Google Groups
> "Ruby on Rails: Talk" group.
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> .
> For more options, visit this group at
> http://groups.google.com/group/rubyonrails-talk?hl=en.
>
>
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Grary

2010-Apr-01 15:05 UTC

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Re: Newbie seeking advice on DRYing up my model validations...

Lasse,

Yes, that was exactly what I needed.

I see I need to explore the specifics of mixing in (which maybe Matz''s
book underserves) -- in this case it was the self.include(base)
expression that was key.

Finally, where attributes refer logically to the same kind of data,
but have different names, I have aliased them to allow the broadest
use of my version of your validation module.

Thanks so much,

Grar

On Apr 1, 9:41 am, Lasse Bunk
<lasseb...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> Hi Grar,
>
> If you have a User model where you want to use some shared validations, you
> could create a module like this – in lib/my_email_validations.rb:
>
>   module MyEmailValidations
>     def self.included(base)
>       base.validates_presence_of :email
>       base.validates_length_of :email, :minimum => 6
>       base.validate :email_must_be_from_valid_provider
>     end
>
>     # example of a custom validator
>     def email_must_be_from_valid_provider
>       errors.add :email, "must be from a valid provider" if
>         email !~ /...@gmail.com$/
>     end
>   end
>
> and in your User model, include them like this:
>
>   class User < ActiveRecord::Base
>     include MyEmailValidations
>   end
>
> Does this solve your problem?
>
> /Lasse
>
> 2010/4/1 Grary <grary.sti...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>
> > Hi,
>
> > Despite close reading of Matz''s Ruby book and Agile Web Dev.
w. Rails,
> > I can''t  figure out how to tackle the challenge of sharing
validation
> > code across models with attributes in common.
>
> > In each of my models I''d like to validate the shared
attributes with a
> > custom validator that includes Rails ActiveRecord::Validations class
> > methods and some of my own validations. My problem is 1) I
don''t know
> > how to pass attribute references to my special method and 2) (mundane)
> > I can''t successfully call any ActiveRecord::Validations class
methods
> > from within my custom method.
>
> > A bit of garbage here, I know, but any thoughts? Is this kind of
> > problem handled by use of certain gems?
>
> > Thanks,
>
> > Grar
>
> > --
> > 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-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
> > .
> > For more options, visit this group at
> >http://groups.google.com/group/rubyonrails-talk?hl=en.
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Lasse Bunk

2010-Apr-01 15:09 UTC

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Re: Re: Newbie seeking advice on DRYing up my model validations...

Nice – glad you could use it :)

/Lasse

2010/4/1 Grary <grary.stimon-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Lasse,
>
> Yes, that was exactly what I needed.
>
> I see I need to explore the specifics of mixing in (which maybe
Matz''s
> book underserves) -- in this case it was the self.include(base)
> expression that was key.
>
> Finally, where attributes refer logically to the same kind of data,
> but have different names, I have aliased them to allow the broadest
> use of my version of your validation module.
>
> Thanks so much,
>
> Grar
>
> On Apr 1, 9:41 am, Lasse Bunk
<lasseb...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > Hi Grar,
> >
> > If you have a User model where you want to use some shared
validations,
> you
> > could create a module like this – in lib/my_email_validations.rb:
> >
> >   module MyEmailValidations
> >     def self.included(base)
> >       base.validates_presence_of :email
> >       base.validates_length_of :email, :minimum => 6
> >       base.validate :email_must_be_from_valid_provider
> >     end
> >
> >     # example of a custom validator
> >     def email_must_be_from_valid_provider
> >       errors.add :email, "must be from a valid provider" if
> >         email !~ /...@gmail.com$/
> >     end
> >   end
> >
> > and in your User model, include them like this:
> >
> >   class User < ActiveRecord::Base
> >     include MyEmailValidations
> >   end
> >
> > Does this solve your problem?
> >
> > /Lasse
> >
> > 2010/4/1 Grary
<grary.sti...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> >
> > > Hi,
> >
> > > Despite close reading of Matz''s Ruby book and Agile Web
Dev. w. Rails,
> > > I can''t  figure out how to tackle the challenge of
sharing validation
> > > code across models with attributes in common.
> >
> > > In each of my models I''d like to validate the shared
attributes with a
> > > custom validator that includes Rails ActiveRecord::Validations
class
> > > methods and some of my own validations. My problem is 1) I
don''t know
> > > how to pass attribute references to my special method and 2)
(mundane)
> > > I can''t successfully call any ActiveRecord::Validations
class methods
> > > from within my custom method.
> >
> > > A bit of garbage here, I know, but any thoughts? Is this kind of
> > > problem handled by use of certain gems?
> >
> > > Thanks,
> >
> > > Grar
> >
> > > --
> > > 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-/JYPxA39Uh4Ykp1iOSErHA@public.gmane.orgm
> .
> > > To unsubscribe from this group, send email to
> > >
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
>
<rubyonrails-talk%2Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%252Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
> >
> > > .
> > > For more options, visit this group at
> > >http://groups.google.com/group/rubyonrails-talk?hl=en.
>
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>
>
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Rails - Apr 2010 - Newbie seeking advice on DRYing up my model validations...

Newbie seeking advice on DRYing up my model validations...

Re: Newbie seeking advice on DRYing up my model validations...

Re: Newbie seeking advice on DRYing up my model validations...

Re: Re: Newbie seeking advice on DRYing up my model validations...