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A Rails form builder plugin with semantically rich and accessible markup.

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Formtastic Sneaky Preview

Formtastic is a Rails FormBuilder DSL (with some other goodies) to make it far easier to create beautiful, semantically rich, syntactically awesome, readily stylable and wonderfully accessible HTML forms in your Rails applications.

The Story

One day, I finally had enough, so I opened up my text editor, and wrote a DSL for how I’d like to author forms:

  <% semantic_form_for @article do |form| %>

    <% form.inputs :name => "Basic" do %>
      <%= form.input :title %>
      <%= form.input :body %>
      <%= form.input :section %>
      <%= form.input :publication_state, :as => :radio %>
      <%= form.input :author %>
      <%= form.input :allow_comments, :label => "Allow commenting on this article" %>
    <% end %>

    <% form.inputs :name => "Advanced" do %>
      <%= form.input :keywords, :required => false, :hint => "Example: ruby, rails, forms" %>
      <%= form.input :extract, :required => false %>
      <%= form.input :description, :required => false %>
      <%= form.input :url_title, :required => false %>
    <% end %>

    <% form.buttons do %>
      <%= form.commit_button %>
    <% end %>

  <% end %>

I also wrote the accompanying HTML output I expected, favoring something very similar to the fieldsets, lists and other semantic elements Aaron Gustafson presented in Learning to Love Forms, hacking together enough Ruby to prove it could be done.

It’s better than SomeOtherFormBuilder because…

  • it can handle ActiveRecord associations (belongs_to, has_many, has_and_belongs_to_many), rendering the appropriate form input
  • there’s heaps of elements, id and class attributes for you to hook in your CSS and JS
  • it’s really quick to get started with a basic form in place (4 lines), then go back to add it more detail if you need it
  • it handles real world stuff line inline hints, inline error messages, help text
  • there’s a bunch of people using and working on it (it’s not just one developer building half a solution)
  • it’s got absolutely awesome spec coverage
  • it doesn’t hijack or change any of the standard Rails form inputs, so you can still use them as expected (even mix and match)


  • web apps = lots of forms
  • forms are so friggin’ boring to code
  • semantically rich & accessible forms really are possible
  • the “V” is way behind the “M” and “C” in Rails’ MVC – it’s the ugly sibling
  • best practices and common patterns have to start somewhere
  • i need a challenge


  • it should be easier to do things the right way than the wrong way
  • sometimes more mark-up is better
  • elements and attribute hooks are gold for stylesheet authors
  • make the common things we do easy, yet still ensure uncommon things are still possible


Forms are really boring to code… you want to get onto the good stuff as fast as possible.

This renders a set of inputs (one for most columns in the database table, and one for each ActiveRecord belongs_to, has_many or has_and_belongs_to_many association) and a submit button:

  <% semantic_form_for @user do |form| %>
    <%= form.inputs %>
    <%= form.buttons %>
  <% end %>

If you want to specify the order of the fields, skip some of the fields or even add in fields that Formtastic couldn’t detect, you can pass in a list of field names to inputs and list of button names to buttons:

  <% semantic_form_for @user do |form| %>
    <%= form.inputs :title, :body, :section, :categories, :created_at %>
    <%= form.buttons :commit %>
  <% end %>

If you want control over the input type Formtastic uses for each field, you can expand the inputs and buttons blocks. This specifies the :section input should be a set of radio buttons (rather than the default select box), and that the :created_at field should be a string (rather than the default datetime selects):

  <% semantic_form_for @post do |form| %>
    <% form.inputs do %>
      <%= form.input :title %>
      <%= form.input :body %>
      <%= form.input :section, :as => :radio %>
      <%= form.input :categories %>
      <%= form.input :created_at, :as => :string %>
    <% end %>
    <% form.buttons do %>
      <%= form.commit_button %>
    <% end %>
  <% end %>

If you want to customize the label text, or render some hint text below the field, specify which fields are required/option, or break the form into two fieldsets, the DSL is pretty comprehensive:

  <% semantic_form_for @post do |form| %>
    <% form.inputs :name => "Basic", :id => "basic" do %>
      <%= form.input :title %>
      <%= form.input :body %>
    <% end %>
    <% form.inputs :name => "Advanced Options", :id => "advanced" do %>
      <%= form.input :slug, :label => "URL Title", :hint => "Created automatically if left blank", :required => false %>
      <%= form.input :section, :as => :radio %>
      <%= form.input :user, :label => "Author", :label_method => :full_name,  %>
      <%= form.input :categories, :required => false %>
      <%= form.input :created_at, :as => :string, :label => "Publication Date", :required => false %>
    <% end %>
    <% form.buttons do %>
      <%= form.commit_button %>
    <% end %>
  <% end %>

Nested forms (Rails 2.3) are also supported:

  <% semantic_form_for @post do |post| %>
    <%= post.semantic_fields_for :author do |author| %>
      <%= author.inputs %>
    <%= end %>
    <%= post.buttons %>
  <% end %>

The Available Inputs

  • :select (a select menu) – default for ActiveRecord associations (belongs_to, has_many, has_and_belongs_to_many)
  • :radio (a set of radio inputs) – alternative to :select for ActiveRecord belongs_to associations
  • :password (a password input) – default for :string column types with ‘password’ in the method name
  • :text (a textarea) – default for :text column types
  • :date (a date select) – default for :date column types
  • :datetime (a date and time select) – default for :datetime and :timestamp column types
  • :time (a time select) – default for :time column types
  • :boolean (a checkbox) – default for :boolean column types
  • :boolean_select (a yes/no select box)
  • :string (a text field) – default for :string column types
  • :numeric (a text field, like string) – default for :integer, :float and :decimal column types
  • :file (a file field) – default for paperclip or attachment_fu attributes

The documentation is pretty good for each of these (what it does, what the output is, what the options are, etc) so go check it out.


If you wish, put something like this in config/initializers/formtastic_config.rb:

  # Should all fields be considered "required" by default
  # Defaults to true, see ValidationReflection notes below
  Formtastic::SemanticFormBuilder.all_fields_required_by_default = false
  # Set the string that will be appended to the labels/fieldsets which are required
  # Default is '<abbr title="required">*</abbr>'
  Formtastic::SemanticFormBuilder.required_string = "(required)"
  # Set the string that will be appended to the labels/fieldsets which are optional
  # Defaults to an empty string ("")
  Formtastic::SemanticFormBuilder.optional_string = "(optional)"

  # Set the way inline errors will be displayed.
  # Defaults to :sentence, valid options are :sentence, :list and :none
  Formtastic::SemanticFormBuilder.inline_errors = :list

  # Set the method to call on label text to transform or format it for human-friendly reading
  # Defaults to :titleize, but you might want :humanize, :to_s, etc
  Formtastic::SemanticFormBuilder.label_str_method = :titleize

  # Set the array of methods to try calling on parent objects in :select and :radio inputs
  # for the text inside each @<option>@ tag or alongside each radio @<input>@.  The first method
  # that is found on the object will be used.
  # Defaults to ["to_label", "display_name", "full_name", "name", "title", "username", "login", "value", "to_s"]
  Formtastic::SemanticFormBuilder.collection_label_methods = ["title_and_author", "display_name", "login", "to_s"]

Internationalization (I18n)

Supports I18n! ActiveRecord object names and attributes are, by default, taken from calling @object.human_name and @object.human_attribute_name(attr) respectively. There are a few words specific to Formtastic that can be translated.

Here is an example locale file:

      yes: 'Yes'
      no: 'No'
      create: 'Create'
      save: 'Save'
      year: 'Year'
      month: 'Month'
      day: 'Day'
      hour: 'Hour'
      minute: 'Minute'
      second: 'Second'

ValidationReflection plugin

If you have the ValidationReflection plugin installed, you won’t have to specify the :required option (it checks the validations on the model instead).



It’s a work in progress and a bit rough around the edges still, but I hope you try it and offer some suggestions and improvements anyway.

On the plus side, it has a comprehensive spec suite and contributions from at least ten independent developers.

Wishlist on the wiki is serving as pretty good documentation for the roadmap to 1.0 and beyond right now, but I’ll work on getting a real tracking system or something happening soon.


There are none, but…

  • if you have the ValidationReflection plugin is installed, you won’t have to specify the :required option (it checks the validations on the model instead)
  • rspec, rspec_hpricot_matchers and rcov gems (plus any of their own dependencies) are required for the test suite


I’m only testing Formtastic with the latest Rails 2.2.x stable release, and it should be fine under Rails 2.3 as well (including nested forms). Patches are welcome to allow backwards compatibility, but I don’t have the energy!

What about Stylesheets?

A proof-of-concept (very much a work-in-progress) stylesheet is provided which you can include in your layout. Customisation is best achieved by overriding these styles in an additional stylesheet so that the formtastic styles can be updated without clobbering your changes.

1. Use the generator to copy the formtastic.css and formtastic_changes.css into your public directory

./script/generate formtastic_stylesheets

2. Add both formtastic.css and formtastic_changes.css to your layout:

<%= stylesheet_link_tag "formtastic" %>
<%= stylesheet_link_tag "formtastic_changes" %>

Extending Formtastic

Adding functionality to Formtastic can be done by subclassing SemanticFormBuilder with your own changes, then telling Formtastic to use yours instead.

To create a new form method that displayed a star rating define the new builder by subclassing SemanticFormBuilder:

  # lib/rating_semantic_form_builder.rb
  class RatingBuilder < Formtastic::SemanticFormBuilder
    # new method to be added allowing full control over the label and value
    def rating(stars, options = {})
      options[:label] ||= 'rating'
      content = input_label(options[:label], options)
      content += @template.content_tag(:span, '*' * stars.to_i, :id => "#{@object_name}_#{options[:label]}")
      @template.content_tag(:li, content)

Set Formtastic’s builder to your newly defined RatingBuilder

  1. RAILS_ROOT/config/initializers/override_formtastic_builder.rb
    require ‘rating_semantic_form_builder.rb’
  1. set the formtastic builder to a customized version of the formtastic builder
    Formtastic::SemanticFormHelper.builder = RatingBuilder

Use semantic_form_for just like you would with Formtastic.

<% semantic_form_for do |form| >
< form.input_field_set :name => “ratings” do >
<= form.rating 5 >
<= form.rating 11, :label => ‘awesomeness (out of 10)’ >
< end >
<= form.buttons >
< end %>

Many thanks to Formtastic’s contributors

Project Info

Formtastic is hosted on Github:, where your contributions, forkings, comments and feedback are greatly welcomed.

There’s also a newly created Formtastic Google Group.

Copyright © 2007-2008 Justin French, released under the MIT license.

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