Rack::Conditional::Forms

Rack::ConditionalForms allows forms to override If-Match and If-Unmodified-Since headers, using _if_match and _if_unmodified_since keys, respectively, allowing conditional POST, PUT and DELETE requests from the browser.

Add this line to your application's Gemfile:

gem 'rack-conditional-forms'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rack-conditional-forms

require 'rack/conditional-forms'
use Rack::ConditionalForms

To use Rack::ConditionalForms in your Rails application, add the following line to your application config file (config/application.rb for Rails 3, config/environment.rb for Rails 2):

config.middleware.use Rack::ConditionalForms

Prepend the hidden fields to your form:

<form action="/123" method="POST">
  <fieldset>
    <input name="_method" type="hidden" value="PUT" />
    <input name="_if_match" type="hidden" value='202cb962ac59075b964b07152d234b70' />
    <input name="_if_unmodified_since" type="hidden" value="Tue, 08 May 2012 00:00:00 GMT" />
    <p>
      <label for="title"></label>
      <input name="title" value="Example form" />
    </p>
    <p>
      <input type="submit" />
    </p>
  </fieldset>
</form>

The request's HTTP_IF_MATCH and HTTP_IF_UNMODIFIED_SINCE headers will then be set to "202cb962ac59075b964b07152d234b70" and Tue, 08 May 2012 00:00:00 GMT, respectively.

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