One of the best things about Ruby on Rails is the incredible, growing community of extraordinary developers willing to share their work with the world. They allow us all to write really cool pieces of functionality (see my post about flickr.rb) in a really short amount of time. Geoffrey Grosenbach (aka topfunky) is one of these fine folks. In addition to his already great Gruff and Sparklines graphing libraries, he’s just published the first cut of his CSS Graphs Helper, which does some basic graphing using pure CSS (i.e. no images) – inspired by the Apples To Oranges article that some of you might have seen.

So, we decided to take the CSS Graphs Helper and create a really quick and dirty, er, poll/voting thingy, complete with Ajax-y goodness… as shown below.

First, follow the instructions on how to install the CSS Graphs Helper plugin. Then, create a couple of tables to hold the questions and choices.

CREATE TABLE `questions` (
  `id` int(11) NOT NULL auto_increment,
  `text` varchar(200) default NULL,
  PRIMARY KEY  (`id`)
)

CREATE TABLE `choices` (
  `id` int(11) NOT NULL auto_increment,
  `question_id` int(11) default NULL,
  `text` varchar(200) default NULL,
  `votes` int(11) default NULL,
  PRIMARY KEY  (`id`)
)

Then, create two Rails models – Question, which has_many Choices, and Choices, which belongs_to question. (Just saved you about a half hour of stored procedure writing :)

Then, you can create a view:

<div id="poll">
        <%= form_remote_tag :url => { :action => 'vote', :id => @question.id }, :update => 'poll' %>
            <p><%=h @question.text %></p>
            <p>
                <% @question.choices.each do |choice| %>
                    <%= radio_button_tag "answer", choice.id %> <%= choice.text %><br/>
                <% end %>
            </p>
        <%= submit_tag "Vote" %>
        <%= end_form_tag %>
</div>

...and partial (for the AJAX stuff):

<h3><%= question.text %></h3>
<p><%= bar_graph *votes %></p>
<p>
    <% question.choices.each do |choice| %>
        <%= "#{choice.text}: #{choice.votes.to_i} votes.<br/>" %>
    <% end %>
</p>

Finally, a controller:

class PollController < ApplicationController

    def index
        @question = Question.find(@params[:id])
    end

    def vote
        question = Question.find(@params[:id])
        choice = Choice.find(@params[:answer])
        choice.votes = choice.votes.to_i + 1
        choice.save
        votes = question.choices.map { |choice| [choice.text, choice.votes.to_i] }
        render :partial => 'results', :locals => { :question => question, :votes => votes }
    end

end

Obviously, some additional styling and such would be really nice, if you were to actually use this in your web application. And, refactoring this into a helper or component would be cool, so that it could be embedded across different pages or applications. But, the moral of the story is, it took me a heck of lot longer to write this post than it did to actually write the code.