DuckForm - QUACK

I found it annoying that the form_for method of building forms only worked with models. DuckForm creates a way to build arbitrary models so you can consistently use the form_for method to build forms throughout your Rails application. Good examples of this are search forms, or login forms.

This can also be useful to hide nastly implementation details for form input that touches multiple models. For example, you have an Account and User and UserRole models. When a user registers, you want to create a new Account and add a role of 'admin' to the Account for that User. You can ask for all of the User and Account details in one form, and implement a #save method on the Registration DuckForm that handles all of these details. Much better than cluttering up your User model with registration specific callback methods.

Installation

Add this line to your Rails application's Gemfile:

gem 'duck_form'

And then execute:

$ bundle

Usage

Create Concrete Classes

Simply extend the DuckForm class, and add attributes. ActiveModel::Validations is included for free!

class Registration < DuckForm
  attr_accessor :email, :password, :password_confirmation, :account_name

  validates :email, :password, :account_name, presence: true
  validates :password, confirmation: true
end

On-the-Fly

You can build your own DuckForms on the fly, for simple cases using DuckForm.build(name, \*attributes, &block) Use a Has to define attributes with default values. Also, if you pass a block, it will be class_evaled so you can define additional methods for your DuckForm.

# in a controller

class SearchesController < ApplicationController
  def search_form
    DuckForm.build "Search", :query, max_results: 10 do  
      def search
        Product.search(query, limit: max_results)
      end
    end
  end
  helper_method :search_form

  def create
    search_form.update_attributes(params[:search])
    results = search_form.search
    respond_with results
  end
end

# in a view (haml)

= form_for search_form do |f|   # will POST to /searches, override the URL if you'd like
  = f.label :query
  = f.text_field :query

  = f.label :max_results
  = f.number_field :max_results

  = f.submit

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request