Rails - Oct 2005 - DRY Method for Converting All Strings to Uppercase.

I''m looking for the most efficient way to convert all of the strings  
in a given model to uppercase.  For instance if I have @users =  
User.find(:all) how would I convert all of the user data to  
uppercase?  Is there a way to do this in the model?

- Jim

Well, it depends when you want it done...  have a look at
ActiveRecord::Callbacks for when it can be done easily, but for
example, you could do this (untested):

class User < ActiveRecord::Base

  before_save :upcase_fields

  # Before the user is saved this is called
  def upcase_fields
    self.name.upcase!
    self.login.upcase!
  end
end

If you wanted to just do it on the fly in your model (less efficient,
but you''re guaranteed never to get a lowercase attribute), you could
override read_attribute in your class, something like (very
untested!!!):

def User < ActiveRecord::Base

  UPCASE_FIELDS = %w{login surname first_name city}

  def read_attribute(attr_name)
    attr = super(attr_name)
    # Upcase the field if it''s marked as such, and not nil
    attr && UPCASE_FIELDS.include?(attr_name) ? attr.upcase : attr
  end

end

UPCASE_FIELDS might be better as a hash, though for small number of
fields it''s probably a negligible difference.

Cheers!

-DF

On 10/25/05, Jim Jeffers
<rails-u78NUfcIof50Y1uG8So6J1aTQe2KTcn/@public.gmane.org>
wrote:
> I''m looking for the most efficient way to convert all of the
strings
> in a given model to uppercase.  For instance if I have @users >
User.find(:all) how would I convert all of the user data to
> uppercase?  Is there a way to do this in the model?
>
> - Jim
>
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

David Felstead wrote:
> def User < ActiveRecord::Base
> 
>   UPCASE_FIELDS = %w{login surname first_name city}
> 
>   def read_attribute(attr_name)
>     attr = super(attr_name)
>     # Upcase the field if it''s marked as such, and not nil
>     attr && UPCASE_FIELDS.include?(attr_name) ? attr.upcase : attr
>   end
> 
> end
Surely if you want to catch *all* string fields, then:

def read_attribute(attr_name)
  a = super(attr_name)
  if a.respond_to? ''upcase'' then a.upcase else a end
end

would be more appropriate?  Or even better:


class String
  def user_filter
    self.upcase
  end
end

class Fixnum
  def user_filter
    self - 42
  end
end

class Hash
  def user_filter
    self.default=''CHUNKY BACON!''
    self
  end
end

module ActiveRecord
  class Base
    def self.filter_name
      "#{self.name.downcase}_filter"
    end
  end
end

class User < ActiveRecord::Base
  def read_attribute(attr_name)
    a = super(attr_name)
    f = self.filter_name
    if a.respond_to? f then a.send(f) else a end
  end
end

But that way lies madness...

-- 
Alex

Thanks guys. The Ruby language is powerful indeed :)

On Oct 25, 2005, at 3:05 AM, Alex Young wrote:
> David Felstead wrote:
>
>> def User < ActiveRecord::Base
>>
>>   UPCASE_FIELDS = %w{login surname first_name city}
>>
>>   def read_attribute(attr_name)
>>     attr = super(attr_name)
>>     # Upcase the field if it''s marked as such, and not nil
>>     attr && UPCASE_FIELDS.include?(attr_name) ? attr.upcase :
attr
>>   end
>>
>> end
>>
>
> Surely if you want to catch *all* string fields, then:
>
> def read_attribute(attr_name)
>   a = super(attr_name)
>   if a.respond_to? ''upcase'' then a.upcase else a end
> end
>
> would be more appropriate?  Or even better:
>
>
> class String
>   def user_filter
>     self.upcase
>   end
> end
>
> class Fixnum
>   def user_filter
>     self - 42
>   end
> end
>
> class Hash
>   def user_filter
>     self.default=''CHUNKY BACON!''
>     self
>   end
> end
>
> module ActiveRecord
>   class Base
>     def self.filter_name
>       "#{self.name.downcase}_filter"
>     end
>   end
> end
>
> class User < ActiveRecord::Base
>   def read_attribute(attr_name)
>     a = super(attr_name)
>     f = self.filter_name
>     if a.respond_to? f then a.send(f) else a end
>   end
> end
>
> But that way lies madness...
>
> -- 
> Alex
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>