#311 Form Builders pro

Dec 26, 2011 | 12 minutes | Views, Refactoring, Forms

Forms often follow a similar pattern with a lot of repetition. Learn how to clean up form views and remove duplication with the help of form builders.

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cbmeeks almost 13 years ago

Wow. Just finished it. One of your best Ryan. And this is exactly what I was looking for. I am using the Twitter Bootstrap now and I plan on wrapping all of this into a bootstrap form builder.

SWEET!

Chris Gunther almost 13 years ago

If you use Formtastic, there's already a gem with a custom builder for bootstrap:
https://github.com/mjbellantoni/formtastic-bootstrap

Jan about 12 years ago

simple_form does not allow all bootstrap classes.

Daniel Mircea almost 13 years ago

In case anyone is wondering on how to use the custom builder by default:

ActionView::Base.default_form_builder = LabeledFormBuilder

Ernest Surudo about 12 years ago

Thanks! Now, using this method I don't need to define a wrapper class in my application_helper.rb

However, how can I add (say) a CSS class to all forms generated with this form builder?

I tried overriding the "initialize" method and editing the options[:html] hash, but this got me nowhere.

Any ideas?

meltzerj almost 13 years ago

This was amazing... thanks for taking the time to explain things so clearly Ryan.

One small question: When refactoring the collection_check_box code, why do you need to pass record_id and attribute through the send method when calling them on record and object, respectively?

UPDATE:

After looking at the ruby send method documentation, is it because record_id and attribute are passed in as symbols?

Nico Ritsche almost 13 years ago

How else would you do it? Hardcoding to .id and a fixed attribute name? record_id is the function name to call to get the id, it could be :id, but also any other function like :permalink for example. attribute needs to be flexible too, otherwise you could use this builder only for one fixed named attribute. Not very practical I guess... ;-)

cbmeeks almost 13 years ago

For anyone who is interested, this is my form builder using the Twitter Bootstrap css framework.

https://gist.github.com/1526162

Daniel Dosen almost 13 years ago

I like the little gems (no pun intended) you pick up watching these - like this is the second or third time I've seen you use the delegate method and I'm starting to use it...

Dan Neumann almost 13 years ago

I really appreciate the thoroughness, like the delegation, the metaprogramming, and including the HABTM example from the other Railscast. Just became a subscriber and this cast was instantly actionable.

Janko Marohnić almost 13 years ago

Does anyone know how to use this custom form builder with fields_for? I've tried passing the :builder option, but it doesn't work.

Janko Marohnić almost 13 years ago

Nevermind, it automatically works if you use nested fields_for, like this (in Haml):

= labeled_form_for @song do |song_form|
  = song_form.fields_for @song.artist do |artist_form|
    ...

doadmin almost 13 years ago

Really great. I customize it to use the new html5 and have an autocompletion on association without javascript.

          ruby
        
class SimpleFormBuilder < ActionView::Helpers::FormBuilder
#...
  def text_field_with_list(name, *args)
    options = args.extract_options!
    options[:list] ||= options[:label].downcase.pluralize
    t = content_tag :datalist, options[:datalist].collect{ |option| content_tag(:option, option) }.join.html_safe, :id => options[:list] if options[:datalist].is_a? Enumerable
    text_field(name, options) + t
  end

  def objectify_options(options)
    super.except(:label, :datalist)
  end
end

          ruby
        
<%=f.text_field_with_list :pseudo_auteur, :label => "Auteur", :datalist => Auteur.pluck(:pseudo)%>

Curtis Ekstrom almost 13 years ago

The entire form can be given a class, for instance to use twitter's bootstrap, through the following:

          ruby
        
def boot_form_for(object, options={}, &block)
    options[:builder] = Bootstrapped
    options[:html] = { :class => "form-horizontal" }
    form_for(object, options, &block)
end

Stephanie H. Chang over 12 years ago

Is there any significant performance penalty for calling object.class.validators_on(name).any? (below) for every field? Would it be measurably better to move this array retrieval to the form level?

          ruby
        
  def field_label(name, *args)
    options = args.extract_options!
    required = object.class.validators_on(name).any? { |v| v.kind_of? ActiveModel::Validations::PresenceValidator }
    label(name, options[:label], class: ("required" if required))
  end

Also, the snap before the delegate refactoring was awesome. Thanks Ryan!