this is totally gonna work…

I stumbled across a little bit of hidden Rails fun last night when I was trying to get the form_for method to stop wrapping error fields with extra div tags. Did you know that? Maybe you never noticed, but when you use the field helper methods, like text_field, password_field, etc, Rails will wrap fields with errors in a <div> with the class ‘fieldWithErrors’.

This was causing all sorts of grief for me in some JavaScript I was trying to write. At first I tried to go with the flow and fix my JS, but it got really hacky really fast. So I went on a little source-code spelunking to figure how to make the problem go away.

In actionpack-2.1.0 there is a Proc attached to the ActionView::Base.field_error_proc class attribute. It’s not documented in the RDoc, but this is also a writable attribute which means I can shut the damn thing up. Here’s what it looks like in the original file, GEM_HOME/actionpack-2.1.0/lib/action_view/helpers/active_record_helper.rb:

require 'cgi'
require 'action_view/helpers/form_helper'

module ActionView
  class Base
    @@field_error_proc = Proc.new{ |html_tag, instance| "<div class=\"fieldWithErrors\">#{html_tag}</div>" }
    cattr_accessor :field_error_proc
  end
  ...
end

My solution was to create a little file in config/initializers named field_errors.rb with this text:

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  html_tag
end

Et voila! Just a simple pass-through with no more fancy-pants markup. Putting stuff like this in separate files in the initializers directory keeps your config and environment files from getting out of hand.

This entry (Permalink) was posted on Tuesday, September 23rd, 2008 at 8:41 am and is filed under Rails. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.