Rails - Mar 2006 - Form helpers and overloaded methods - help!

Can someone explain why form helpers appear to bypass any model methods
I override for fields that are bound to database fields? It would be
great if someone could tell me how to force the form field, etc to call
the method instead of looking at the database / attributes collection.

Let''s say I have a column called ''price'' in my
database table "books"

Let''s say I want price to always come back as a special format when I
query my model.... So in my model, I do

   def price
      number_with_precision(self.attributes[:price])
   end

In a view, @book.price comes back formatted correctly as expected.

However,  <%=text_field "book", "price" %> bypasses my
method and gets
the unformatted price. 

It just doesn''t seem consistent. I''m currenly playing around
with a hack
to form_helper et all, but it''s kinda complicated and so I was looking
for an explanation or an easy workaround. (I know I can set the
precision in my db to accomplish this issue but this is just an
example.)


Thanks much to anyone willing to help.




Brian Hogan
Web Development
Learning & Technology Services
Schofield 3-B
University of Wisconsin-Eau Claire
715 836 3585
hoganbp@uwec.edu



Brian Hogan
Web Development
Learning & Technology Services
Schofield 3-B
University of Wisconsin-Eau Claire
715 836 3585
hoganbp@uwec.edu

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Well, here''s the code that makes the form tags look at the database
directly. Is there a reason why I shouldn''t comment out these lines
below? Basically, I''m asking the core team why they decided to look at
the database first.
 
module ActionView
  module Helpers
      class InstanceTag
 
          def value_before_type_cast
            unless object.nil?
            #  object.respond_to?(@method_name + "_before_type_cast")
?
            #  object.send(@method_name + "_before_type_cast") :
                object.send(@method_name)
            end
 
        end
    end    
end
 
 
 
-----Original Message-----
From: rails-bounces@lists.rubyonrails.org
[mailto:rails-bounces@lists.rubyonrails.org] On Behalf Of Hogan, Brian
P.
Sent: Wednesday, March 01, 2006 2:59 PM
To: rails@lists.rubyonrails.org
Subject: [Rails] Form helpers and overloaded methods - help!



Can someone explain why form helpers appear to bypass any model methods
I override for fields that are bound to database fields? It would be
great if someone could tell me how to force the form field, etc to call
the method instead of looking at the database / attributes collection.

Let''s say I have a column called ''price'' in my
database table "books"

Let''s say I want price to always come back as a special format when I
query my model.... So in my model, I do 

   def price 
      number_with_precision(self.attributes[:price]) 
   end 

In a view, @book.price comes back formatted correctly as expected. 

However,  <%=text_field "book", "price" %> bypasses my
method and gets
the unformatted price. 

It just doesn''t seem consistent. I''m currenly playing around
with a hack
to form_helper et all, but it''s kinda complicated and so I was looking
for an explanation or an easy workaround. (I know I can set the
precision in my db to accomplish this issue but this is just an
example.)


Thanks much to anyone willing to help. 




Brian Hogan 
Web Development 
Learning & Technology Services 
Schofield 3-B 
University of Wisconsin-Eau Claire 
715 836 3585 
hoganbp@uwec.edu 



Brian Hogan 
Web Development 
Learning & Technology Services 
Schofield 3-B 
University of Wisconsin-Eau Claire 
715 836 3585 
hoganbp@uwec.edu 

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Brian,

I have the same problem. I don''t have an answer for you but I think the
more
appropriate place to modify the code is at (line after !!! comment):

def to_input_field_tag(field_type, options = {})
  options = options.stringify_keys
  options["size"] ||= options["maxlength"] ||
DEFAULT_FIELD_OPTIONS["size"]
  options = DEFAULT_FIELD_OPTIONS.merge(options)
  if field_type == "hidden"
    options.delete("size")
  end
  options["type"] = field_type
  # !!! options["value"] ||= value_before_type_cast unless field_type
==
"file"
  options["value"] ||= value unless field_type == "file"
  add_default_name_and_id(options)
  tag("input", options)
end

I have a suspicion that value_before_type_cast was used for things that
don''t
degrade well to a string after type casting.

What is interesting is it appears that the typical form processing is not 
symmetrical, when I instantiate an object using the form parameters when 
processing the submit, it does go through the overridden methods.

For now, I have made the above change in my development environment and am 
continuing to test with it.

Eric

i`m in the same situation and did the following in view:
<%= text_field_tag(''book[price]'', @book.price) %>

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