Ruby on Rails, Ajax & CSS Star Rating System
I’m sure everyone by now has seen those oh-so-Web 2.0 star rating features on hundreds of websites. Well I needed to implement one for a site I’m working on and I couldn’t find a complete example anywhere (not in RoR). So here it is. A complete Rails based Ajax and CSS star ratings sytem with some RJS thrown in for good measure.
I used Rogie’s very elegant CSS only star rating system found here CSS Star Rating Part Deux. I also used Chris Ingrassia’s acts_as_rateable plugin.
So here we go.
Get the CSS and change the image url’s
First figure out which version of the CSS ratings you like. I used this example.
/* styles for the star rater */ .star-rating{ list-style:none; margin: 0px; padding:0px; width: 150px; height: 30px; position: relative; background: url(/images/star_rating.gif) top left repeat-x; } .star-rating li{ padding:0px; margin:0px; /*\*/ float: left; /* */ } .star-rating li a{ display:block; width:30px; height: 30px; text-decoration: none; text-indent: -9000px; z-index: 20; position: absolute; padding: 0px; } .star-rating li a:hover{ background: url(/images/star_rating.gif) left center; z-index: 2; left: 0px; border:none; } .star-rating a.one-star{ left: 0px; } .star-rating a.one-star:hover{ width:30px; } .star-rating a.two-stars{ left:30px; } .star-rating a.two-stars:hover{ width: 60px; } .star-rating a.three-stars{ left: 60px; } .star-rating a.three-stars:hover{ width: 90px; } .star-rating a.four-stars{ left: 90px; } .star-rating a.four-stars:hover{ width: 120px; } .star-rating a.five-stars{ left: 120px; } .star-rating a.five-stars:hover{ width: 150px; } .star-rating li.current-rating{ background: url(/images/star_rating.gif) left bottom; position: absolute; height: 30px; display: block; text-indent: -9000px; z-index: 1; }Make sure you change your image url’s so that your Rails app can find them.
Get the images for your CSS
Grab the images used in your CSS and put them in your images directory. Here are both
Install the acts_as_rateable plugin.
Run the following from the root of your Rails app to install the plugin.
script/plugin install http://juixe.com/svn/acts_as_rateable
Create the tables used by acts_as_rateable
Create a file db/migrate/xxx_create_ratings.rb (xxx is 001 if it’s the first migration file you have).
class CreateRatings< ActiveRecord::Migration def self.up create_table :ratings, :force => true do |t| t.column :rating, :integer, :default => 0 t.column :created_at, :datetime, :null => false t.column :rateable_type, :string, :limit => 15, :default => "", :null => false t.column :rateable_id, :integer, :default => 0, :null => false t.column :user_id, :integer, :default => 0, :null => false end add_index :ratings, ["user_id"], :name => "fk_ratings_user" end def self.down drop_table :ratings endend
Run your migration.
rake migrate
You should now have the appropriate tables.
Make one of your models rateable
I was trying to add a rating system for the model Asset. Yours can obviously be whatever you like but from here on out I’ll be using Asset. So add acts_as_rateable to your model.
class Asset < ActiveRecord::Base acts_as_rateable ...end
Create a controller to handle the rating submissions
Create the file /controllers/rating_controller.rb
class RatingController < ApplicationController def rate @asset = Asset.find(params[:id]) Rating.delete_all(["rateable_type = 'Asset' AND rateable_id = ? AND user_id = ?", @asset.id, current_user.id]) @asset.add_rating Rating.new(:rating => params[:rating], :user_id => current_user.id) endend
Two things to note here. First I’m associating ratings to users. I’ve already implemented a user/permission system for my site using the model User. Use whatever is appropriate for you. You can modify this whole example to work without associating ratings to users, the acts_as_rateable plugin will handle it just fine. However, I’m not going to get into that here.
Since I am associating ratings to users it would be bad to have a user skew the results by storing multiple ratings for a single Asset. Hence the delete. I’m telling it to delete all ratings for the rateable_type ‘Asset’ and the id (rateable_id) of the Asset. The rateable_type of Asset is handled by the plugin and stored in the ratings table.
Create your views
Create the partial /views/rating/_rating.rhtml
<%= number_with_precision(asset.rating, 1) %>/5 Stars<br><ul class='star-rating'> <li class='current-rating' style='width:<%= (asset.rating * 30).to_i -%>px;'> Currently <%= number_with_precision(asset.rating, 1) %>/5 Stars. </li> <li> <%= link_to_remote( "1", {:url => { :controller => "rating_demo", :action => "rate", :id => asset.id, :rating => 1}}, :class => 'one-star', :name => '1 star out of 5') %> </li> <li> <%= link_to_remote( "2", {:url => { :controller => "rating_demo", :action => "rate", :id => asset.id, :rating => 2}}, :class => 'two-stars', :name => '2 stars out of 5') %> </li> <li> <%= link_to_remote( "3", {:url => { :controller => "rating_demo", :action => "rate", :id => asset.id, :rating => 3}}, :class => 'three-stars', :name => '3 stars out of 5') %> </li> <li> <%= link_to_remote( "4", {:url => { :controller => "rating_demo", :action => "rate", :id => asset.id, :rating => 4}}, :class => 'four-stars', :name => '4 stars out of 5') %> </li> <li> <%= link_to_remote( "5", {:url => { :controller => "rating_demo", :action => "rate", :id => asset.id, :rating => 5}}, :class => 'five-stars', :name => '5 stars out of 5') %> </li></ul>Obviously it’s using Ajax with the prototype helper link_to_remote to submit the user’s rating. One thing to note. Where you see width:<= (asset.rating * 30).to_i ->px;’ you’ll have to modify this to correspond with the images you chose to use. The one I’m using has images which are 30px wide. If you chose the smaller star images then you’ll have to modify this calculation to correspond to your image width. By the way, this is the line that handles the display of the current rating.
And now a little RJS
Create the file /views/rating/rate.rjs
page.replace_html "star-ratings-block", :partial => 'rating/rating', :locals => { :asset => @asset }This will replace the star ratings with the partial we created previously in order to reflect any rating changes made by the submission.
And finally put it on your page
Render the partial in one of your views.
<div id="star-ratings-block"> <%= render :partial => "rating/rating", :locals => { :asset => @asset } %></div>This needs @asset (or whatver you’re going to be using) in order to function.
Done
Now wasn’t that easy? Gotta love rails. 10 minutes of coding and you have a complete Ajax and CSS star rating system just like the pros use. Here’s a demo.
I could very well have skipped something so let me know if you have any problems.
Washington DC Ruby on Rails Users Group
I’m creating a Washington DC area Ruby on Rails Users Group. If you’re interested in getting involved check out www.dcrug.org for more information.
Receiving Emails and Attachments with Rails
Does your Rails app need to handle incoming emails with the attachments? All of the examples I’ve seen so far show you how to insert email attachments into the DB. Here’s a quick example that uses RailsCron to poll a POP3 account every minute for new emails and stores the attachments on the filesystem. If you need help using or running RailsCron see my previous posts about the topic.
The Agile book has a good example that kicks off a runner script but I think this method is far more efficient than having your mail system kick off a separate runner every time a new email is received, especially if you’re dealing in high volume.
It also handles non-responsive or slow responding POP3 servers by setting a high timeout length and retrying a handful of times before it gives up.
This class will check for and hand off any incoming emails:
require 'net/pop'class EmailQueue < ActiveRecord::Base background :poll_mail, :every => 1.minute, :concurrent => false def self.poll_mail retrycount = 0 begin timeout(600) do Net::POP3.start("yourdomain.com", nil, "username", "password") do |pop| if pop.mails.empty? logger.info "NO MAIL" else pop.mails.each do |email| begin logger.info "receiving mail..." AssetSubmitHandler.receive(email.pop) email.delete rescue Exception => e logger.error "Error receiving email at " + Time.now.to_s + "::: " + e.message end end end end end rescue TimeoutError if(retrycount < 5) retrycount+=1 retry else logger.info("ERROR Timeout error in poll_mail attempt #" + retrycount.to_s) nil end end rescue Exception => exception SystemNotifier.deliver_exception_notification(exception) logger.info("Error in poll_mail") logger.info(exception.class.to_s + " " + exception.message.to_s + " " + exception.backtrace.to_s) endendAnd here’s the code that handles the email:
class AssetSubmitHandler < ActionMailer::Base # content type should be validated to image/gif, image/jpg, or image/jpeg def receive(email) if email.has_attachments? email.attachments.each do |attachment| asset = Asset.new asset.submitter = email.from.first asset.name = base_part_of(attachment.original_filename) asset.content_type = attachment.content_type.chomp base_dir = "/home/someapp/www/" # save original file asset.original = "assets/o_#{Time.now.utc.to_i}#{rand(1000000)}."+asset.name File.open(base_dir+asset.original,File::CREAT|File::TRUNC|File::WRONLY,0666){ |f| f.write(attachment.read) } asset.save end end end def base_part_of(file_name) name = File.basename(file_name) name.gsub(/[^W._-]/, '') sanitize_filename(name) end # Fixes a 'feature' of IE where it passes the entire path instead of just the filename def sanitize_filename(value) #get only the filename (not the whole path) just_filename = value.gsub(/^.*(\\|\/)/, '') just_filename.gsub(/[^\w\.\-]/,'_') endend
My site in an O'Reilly book
I just found out recently that one of my webpages was featured in an O’Reilly book:
Google Maps Hacks: Tips & Tools for Geographic Searching and Remixing
Ok, so it’s a pretty simple page but nonetheless I think it’s pretty cool.
Rails Security Issue and Fix
If you’re running Ruby on Rails you should do an update immediately to get the fix for a newly found security issue.
Here’s some more info about it.
To upgrade run:
gem install rails --include-dependencies
Rails 1.0 and earlier versions as well as Rails 1.1.3 aren’t affected.
If you want to freeze your particular version of Rails for an app go to the root directory of that app and run:
rake rails:freeze:gems
Note: The last release of rails (1.1.5) only solves part of the security problem. Update rails today to get 1.1.6.
