require 'active_support/core_ext/object/try' require 'rails-html-sanitizer' module ActionView # = Action View Sanitize Helpers module Helpers # The SanitizeHelper module provides a set of methods for scrubbing text of undesired HTML elements. # These helper methods extend Action View making them callable within your template files. module SanitizeHelper extend ActiveSupport::Concern # This +sanitize+ helper will HTML encode all tags and strip all attributes that # aren't specifically allowed. # # It also strips href/src tags with invalid protocols, like javascript: especially. # It does its best to counter any tricks that hackers may use, like throwing in # unicode/ascii/hex values to get past the javascript: filters. Check out # the extensive test suite. # # <%= sanitize @article.body %> # # You can add or remove tags/attributes if you want to customize it a bit. # See ActionView::Base for full docs on the available options. You can add # tags/attributes for single uses of +sanitize+ by passing either the # :attributes or :tags options: # # Normal Use # # <%= sanitize @article.body %> # # Custom Use - Custom Scrubber # (supply a Loofah::Scrubber that does the sanitization) # # scrubber can either wrap a block: # scrubber = Loofah::Scrubber.new do |node| # node.text = "dawn of cats" # end # # or be a subclass of Loofah::Scrubber which responds to scrub: # class KittyApocalypse < Loofah::Scrubber # def scrub(node) # node.text = "dawn of cats" # end # end # scrubber = KittyApocalypse.new # # <%= sanitize @article.body, scrubber: scrubber %> # # A custom scrubber takes precedence over custom tags and attributes # Learn more about scrubbers here: https://github.com/flavorjones/loofah # # Custom Use - tags and attributes # (only the mentioned tags and attributes are allowed, nothing else) # # <%= sanitize @article.body, tags: %w(table tr td), attributes: %w(id class style) %> # # Add table tags to the default allowed tags # # class Application < Rails::Application # config.action_view.sanitized_allowed_tags = ['table', 'tr', 'td'] # end # # Remove tags to the default allowed tags # # class Application < Rails::Application # config.after_initialize do # ActionView::Base.sanitized_allowed_tags.delete 'div' # end # end # # Change allowed default attributes # # class Application < Rails::Application # config.action_view.sanitized_allowed_attributes = ['id', 'class', 'style'] # end # # Please note that sanitizing user-provided text does not guarantee that the # resulting markup is valid (conforming to a document type) or even well-formed. # The output may still contain e.g. unescaped '<', '>', '&' characters and # confuse browsers. # def sanitize(html, options = {}) self.class.white_list_sanitizer.sanitize(html, options).try(:html_safe) end # Sanitizes a block of CSS code. Used by +sanitize+ when it comes across a style attribute. def sanitize_css(style) self.class.white_list_sanitizer.sanitize_css(style) end # Strips all HTML tags from the +html+, including comments. This uses # Nokogiri for tokenization (via Loofah) and so its HTML parsing ability # is limited by that of Nokogiri. # # strip_tags("Strip these tags!") # # => Strip these tags! # # strip_tags("Bold no more! See more here...") # # => Bold no more! See more here... # # strip_tags("
Welcome to my website!
") # # => Welcome to my website! def strip_tags(html) self.class.full_sanitizer.sanitize(html) end # Strips all link tags from +text+ leaving just the link text. # # strip_links('Ruby on Rails') # # => Ruby on Rails # # strip_links('Please e-mail me at me@email.com.') # # => Please e-mail me at me@email.com. # # strip_links('Blog: Visit.') # # => Blog: Visit. def strip_links(html) self.class.link_sanitizer.sanitize(html) end module ClassMethods #:nodoc: attr_writer :full_sanitizer, :link_sanitizer, :white_list_sanitizer # Vendors the full, link and white list sanitizers. # Provided strictly for compabitility and can be removed in Rails 5. def sanitizer_vendor Rails::Html::Sanitizer end def sanitized_allowed_tags sanitizer_vendor.white_list_sanitizer.allowed_tags end def sanitized_allowed_attributes sanitizer_vendor.white_list_sanitizer.allowed_attributes end # Gets the Rails::Html::FullSanitizer instance used by +strip_tags+. Replace with # any object that responds to +sanitize+. # # class Application < Rails::Application # config.action_view.full_sanitizer = MySpecialSanitizer.new # end # def full_sanitizer @full_sanitizer ||= sanitizer_vendor.full_sanitizer.new end # Gets the Rails::Html::LinkSanitizer instance used by +strip_links+. # Replace with any object that responds to +sanitize+. # # class Application < Rails::Application # config.action_view.link_sanitizer = MySpecialSanitizer.new # end # def link_sanitizer @link_sanitizer ||= sanitizer_vendor.link_sanitizer.new end # Gets the Rails::Html::WhiteListSanitizer instance used by sanitize and +sanitize_css+. # Replace with any object that responds to +sanitize+. # # class Application < Rails::Application # config.action_view.white_list_sanitizer = MySpecialSanitizer.new # end # def white_list_sanitizer @white_list_sanitizer ||= sanitizer_vendor.white_list_sanitizer.new end ## # :method: sanitized_allowed_tags= # # :call-seq: sanitized_allowed_tags=(tags) # # Replaces the allowed tags for the +sanitize+ helper. # # class Application < Rails::Application # config.action_view.sanitized_allowed_tags = ['table', 'tr', 'td'] # end # ## # :method: sanitized_allowed_attributes= # # :call-seq: sanitized_allowed_attributes=(attributes) # # Replaces the allowed HTML attributes for the +sanitize+ helper. # # class Application < Rails::Application # config.action_view.sanitized_allowed_attributes = ['onclick', 'longdesc'] # end # end end end end