SanitizeAttributes

This is a simple plugin for ActiveRecord models to define sanitizable attributes. When an object is saved, those attributes will be run through whatever filter you’ve defined. You can define a default filter for all sanitizations.

Sanitization only happens for non-nil attributes. (Because a nil attribute may be valid for your model, and the sanitzers should only have to worry about working with strings.)

This plugin was created to implement anti-XSS validation. My gem of choice is Sanitize: github.com/rgrove/sanitize/tree/master

For Rails 3, add this line to your Gemfile:

gem 'sanitize_attributes', :git => "[email protected]:devp/sanitize_attributes.git"

For Rails 2.3, it should work when installed as a plugin:

./script/plugin install [email protected]:devp/sanitize_attributes.git

Example

# config/initializers/sanitize_attributes.rb
SanitizeAttributes.default_sanitization_method = lambda do |text|
  text.gsub(/[^\w\s]/, "") # very simple, very limited
end

# app/models/bookmark.rb
class Bookmark
  sanitize_attributes :sitename
end

# app/models/article.rb
class Article   
  sanitize_attributes :title, :author

  sanitize_attributes :body do |body_text|
    # This needs to be safe, renderable HTML, so let's use a real sanization tool
    # I recommend: http://github.com/rgrove/sanitize/tree/master 
    Sanitize.clean(body_text)
  end
end 

Article.default_sanitization_method_for_class = lambda do |text|
  text.gsub(/[^\w\s\'".,?!]/, "") # more reasonable, for titles and such
end

# in action...
b = Bookmark.create(:sitename => "boston.rb!!!", :url => "http://http://bostonrb.org/")
b.sitename # => "bostonrb"
a = Article.create(:title => "<b>Hello</b>!", :body => "Please remove the <script>script tags</script>!")
a.title # => "Hello!"
a.body  # => "Please remove the script tags!"

Future Work

Things to work on in the future:

allowing strings/symbols for sanitization methods, not just blocks

Nacho.default_sanitization_method_for_class = :microwave # uses Nacho.microwave
Nacho.default_sanitization_method_for_class = "Sanitize.clean"

add validation helpers, if you want to flag problematic text rather than cleaning it.

class Foo
```
validate_sanitized :value
```
end Foo.new(:value => “abc”).valid? #=> false if a sanitized copy of #value is different than the original
better functionality for subclasses. Currently, they will share sanitized attributes and sanitization methods across subclasses and the base class.

Etc

Thanks to contributors:

Josh Nichols
Michael Reinsch
Paul McMahon