Rails - Sep 2005 - WhitespaceKiller

Hi,

I am trying to use the WhitespaceKiller as referenced here:

http://wiki.rubyonrails.com/rails/show/HowToStripWhitespaceFromModelFields

However, it does not work for attr_accessors such as:

  attr_accessor :password

Here is an inspect snippet of my User object:

<User:0x3865798 @password_confirmation="", @password="",
@attributes={"name"=>"Tom Davies",
"address1"=>"123 No Way", ...}>

The WhitespaceKiller only loops through the attributes (which the
attr_accessors are not part of) using this code:

  def before_validation(record)
    record.attributes.each do | attr, val|
      if !val.nil? && val.respond_to?(:strip)
        s = val.strip
        s.size == 0? record[attr] = nil : record[attr] = s
      end
    end
  end

Is there a concise way to modify that method to include the attr_accessors?

Thanks,
Tom

Tom Davies wrote:
> The WhitespaceKiller only loops through the attributes (which the
> attr_accessors are not part of) using this code:
> 
> Is there a concise way to modify that method to include the attr_accessors?
Something like:

def before_validation(record)
   for var in record.instance_variables.collect {|v| v[1..-1]} -
[''attributes'',''new_record''] +
record.attribute_names
     setter_meth = var + ''=''
     if record.respond_to?(var) && record.respond_to?(setter_meth)
       val = record.send(var)
       if !val.nil? && val.respond_to?(:strip)
         s = val.strip
         record.send(setter_meth, s.size == 0 ? nil : s)
       end
     end
   end
end

-- 
We develop, watch us RoR, in numbers too big to ignore.

Thanks!  That seems to do the trick. I just have one question.

If I try to test it by replacing the record with an instance of my
model User class, it does not pick up the attr_accessors.  For
example:

<% @user = User.new
for var in @user.instance_variables.collect {|v| v[1..-1]} -
[''attributes'',''new_record''] +
@user.attribute_names %>
<%= var %>
<% end %>

Is the record passed to the Observer methods something other than a
direct instance of the model class?

Thanks again,
Tom

On 9/14/05, Mark Reginald James
<mrj-bzGI/hKkdgQnC9Muvcwxkw@public.gmane.org>
wrote:
> Tom Davies wrote:
> 
> > The WhitespaceKiller only loops through the attributes (which the
> > attr_accessors are not part of) using this code:
> >
> > Is there a concise way to modify that method to include the
attr_accessors?
> 
> Something like:
> 
> def before_validation(record)
>    for var in record.instance_variables.collect {|v| v[1..-1]} -
[''attributes'',''new_record''] +
record.attribute_names
>      setter_meth = var + ''=''
>      if record.respond_to?(var) && record.respond_to?(setter_meth)
>        val = record.send(var)
>        if !val.nil? && val.respond_to?(:strip)
>          s = val.strip
>          record.send(setter_meth, s.size == 0 ? nil : s)
>        end
>      end
>    end
> end
> 
> --
> We develop, watch us RoR, in numbers too big to ignore.
> 
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Tom Davies wrote:
> Thanks!  That seems to do the trick. I just have one question.
> 
> If I try to test it by replacing the record with an instance of my
> model User class, it does not pick up the attr_accessors.  For
> example:
> 
> <% @user = User.new
> for var in @user.instance_variables.collect {|v| v[1..-1]} -
> [''attributes'',''new_record''] +
@user.attribute_names %>
> <%= var %>
> <% end %>
> 
> Is the record passed to the Observer methods something other than a
> direct instance of the model class?
It''ll only pick up attr_accessors that have been set to some value
in the instance.

Also, if you want to get a separate list of the accessors, and also to
increase efficiency, you could move the respond_to?s out of the loop.

e.g.

inst_vars = record.instance_variables.collect {|v| v[1..-1]} -
[''attributes'',''new_record'']
accessors = ivars.delete_if { |iv| !(record.respond_to?(iv) &&
record.respond_to?(iv+''='')) }
for var in accessors + record.attribute_names
   val = record.send(var)
   if !val.nil? && val.respond_to?(:strip)
     s = val.strip
     record.send(var+''='', s.size == 0 ? nil : s)
   end
end



-- 
We develop, watch us RoR, in numbers too big to ignore.

Thanks Mark.  I added your first reply to the WhitespaceKiller wiki
page.  I am not too concerned with efficiency here... as the number of
accessors and attributes is very small for all of my models...  but I
appreciate your help.

Tom

On 9/15/05, Mark Reginald James
<mrj-bzGI/hKkdgQnC9Muvcwxkw@public.gmane.org>
wrote:
> Tom Davies wrote:
> > Thanks!  That seems to do the trick. I just have one question.
> >
> > If I try to test it by replacing the record with an instance of my
> > model User class, it does not pick up the attr_accessors.  For
> > example:
> >
> > <% @user = User.new
> > for var in @user.instance_variables.collect {|v| v[1..-1]} -
> > [''attributes'',''new_record''] +
@user.attribute_names %>
> > <%= var %>
> > <% end %>
> >
> > Is the record passed to the Observer methods something other than a
> > direct instance of the model class?
> 
> It''ll only pick up attr_accessors that have been set to some value
> in the instance.
> 
> Also, if you want to get a separate list of the accessors, and also to
> increase efficiency, you could move the respond_to?s out of the loop.
> 
> e.g.
> 
> inst_vars = record.instance_variables.collect {|v| v[1..-1]} -
[''attributes'',''new_record'']
> accessors = ivars.delete_if { |iv| !(record.respond_to?(iv) &&
record.respond_to?(iv+''='')) }
> for var in accessors + record.attribute_names
>    val = record.send(var)
>    if !val.nil? && val.respond_to?(:strip)
>      s = val.strip
>      record.send(var+''='', s.size == 0 ? nil : s)
>    end
> end
> 
> 
> 
> --
> We develop, watch us RoR, in numbers too big to ignore.
> 
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>