Client Side Validations

Now you can easily drop in client side validations in any Rails app. It will use validations defined in a given ActiveRecord (or ActiveModel) class for use with a Javascript form validator. (currently only jquery.validate is supported)

The concept is simple:

1. Define validations in the model as you normally would
2. Provide a publicly available route that render client_side_validations from the instance of the model
3. The validations are sent to the client in JSON
4. client_side_validations.js converts the JSON for a given validation plugin and binds the validator to the form

Currently the following validations are supported:

• validates_presence_of
• validates_format_of
• validates_numericality_of
• validates_length_of

Installation

gem install client_side_validations

Rails 2

Add "config.gem :client_side_validations" to the "config/environment.rb" file

Then run the generator:

script/generate client_side_validations

This will copy client_side_validations.js to "public/javascripts"

Rails 3

Add "gem 'client_side_validations" to the Gemfile

Then run the generator:

rails g client_side_validations

This will copy client_side_validations.js to "public/javascripts"

Configuration

Currently only jquery.validate is supported so you will need to download jQuery and the jQuery Validate plugin to "public/javascripts"

Model

Validate your models as you normally would

class Book < ActiveRecord::Base
  validates_presence_of :author
end

Controller

The controller action just needs to render the validations in JSON. From an instance of the model.

...
def new
  @book = Book.new
  respond_to do |format|
    format.html
    format.json { render :json => @book.validations_to_json(:author) }
  end
end
...

Layout

You currently need both jQuery and the jQuery Validate plugin loaded before you load Client Side Validations

...
<%= javascript_include_tag 'jquery', 'jquery.validate', 'client_side_validations' %>
...

View

Have a form ask for client side validations by passing :validate to form_for and pass the url of the action defined in the controller

...
<% form_for @book, :validations => { :url => new_book_path(:format => :json) } do |b| %>
   <%= b.label :author %></br>
   <%= b.text_field :author %></br>
   <%= submit_tag 'Create' %>
<% end %>
...

That should be it!

Copyright (c) 2010 Democratic National Committee. See LICENSE for details.