Rails 3 rateable model - How to create ajax rating?

Question

How do I create some simple ajax rating like there is on this page http://watir.com/documentation/ ? Every visitor should be able to rate, I dont need to set permissions. I

Answer 1

What I did recently to add a simple rating mechanism to an existing project was the following:

I added two fields to an existing table (which contained the items to be rated). Those were:

rating_score => The current score
ratings => The number of ratings which led to the score

For example, if five users would've voted "5" for the current item, rating_score would be 25, and ratings would be 5. The current rating would be computed as rating_score / ratings.

Then I added a new method to the controller of the items to be rated, called "rate", which looked something like:

def rate
    @item = Item.find(params[:id])
    @container = "item"+@item.id.to_s

    @item.rating_score += params[:rating].to_i
    @item.ratings += 1
    @item.save

    respond_to do |format|
        format.js
    end
end

My view for that method, called rate.js.erb, would look something like

$('#<%= @container %>').html('<%= escape_javascript(render(partial: 'rating', locals: { item: @item })) %>');

This code works only if you've got jQuery installed, but it should be easily translatable to Prototype or whatever JS framework you may be using.

And the partial for the rating, called _rating.html.erb, was something like:

<%= form_tag url_for(controller: 'items',  action: 'rate', id: item.id), remote: true %>
    <%= rating_stars(item.rating_score, item.ratings) %>
    <%= item.ratings %> Votes

In this partial, the rating_stars() helper method generated some kind of star-like representation for the rating, but you can do that however you like.

By setting "remote: true" in the form_tag helper, your Rails installation should automatically transmit the request via the installed Javascript framework. This magic is part of the whole unobtrusive javascript thing going on in Rails lately, which is actually pretty cool.

Hope this gives you an idea of how to realize a very simple rating system with no IP lock feature whatsoever in Rails.