Showing reviews on package's details page from Ubuntu

app/models/package.rb

@@ -1,3 +1,6 @@
+require 'open-uri'  # allows to load URLs using open()
+require 'json'
+
 class Package < ActiveRecord::Base
   # PostgreSQL-based full-text search:
   # https://github.com/Casecommons/pg_search
@@ -57,6 +60,20 @@ class Package < ActiveRecord::Base
     self.screenshots.to_a.sort { |x,y| version_compare(x.version,y.version) }
   end
 
+  # Get reviews of this package from the Ubuntu API
+  def ubuntu_reviews
+    # Use the URL defined in the configuration to get a JSON string
+    json = open(Rails.configuration.ubuntu_reviews_api_url % self.name).read
+    # Turn JSON into a Ruby data structure
+    json = JSON.parse(json)
+    # Only show english reviews
+    # TODO: Support further languages
+    json = json.select {|x| x['language']=='en'}
+    # Sort by 'usefulness_total' (how many people found this review useful)
+    json = json.sort { |x,y| y['usefulness_total'].to_i <=> x['usefulness_total'].to_i}
+    return json
+  end
+
   # Return the newest screenshot that is not newer than the given version.
   # This algorithm collects all image
   # versions of a package and determines the (second) newest version.