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Diffstat (limited to 'actionview/lib/action_view/helpers/sanitize_helper.rb')
| -rw-r--r-- | actionview/lib/action_view/helpers/sanitize_helper.rb | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/actionview/lib/action_view/helpers/sanitize_helper.rb b/actionview/lib/action_view/helpers/sanitize_helper.rb new file mode 100644 index 0000000000..f4fa133f55 --- /dev/null +++ b/actionview/lib/action_view/helpers/sanitize_helper.rb @@ -0,0 +1,177 @@ +# frozen_string_literal: true + +require "active_support/core_ext/object/try" +require "rails-html-sanitizer" + +module ActionView + # = Action View Sanitize Helpers + module Helpers #:nodoc: + # 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 + # Sanitizes HTML input, stripping all but known-safe tags and attributes. + # + # It also strips href/src attributes with unsafe protocols like + # <tt>javascript:</tt>, while also protecting against attempts to use Unicode, + # ASCII, and hex character references to work around these protocol filters. + # All special characters will be escaped. + # + # The default sanitizer is Rails::Html::WhiteListSanitizer. See {Rails HTML + # Sanitizers}[https://github.com/rails/rails-html-sanitizer] for more information. + # + # Custom sanitization rules can also be provided. + # + # Please note that sanitizing user-provided text does not guarantee that the + # resulting markup is valid or even well-formed. + # + # ==== Options + # + # * <tt>:tags</tt> - An array of allowed tags. + # * <tt>:attributes</tt> - An array of allowed attributes. + # * <tt>:scrubber</tt> - A {Rails::Html scrubber}[https://github.com/rails/rails-html-sanitizer] + # or {Loofah::Scrubber}[https://github.com/flavorjones/loofah] object that + # defines custom sanitization rules. A custom scrubber takes precedence over + # custom tags and attributes. + # + # ==== Examples + # + # Normal use: + # + # <%= sanitize @comment.body %> + # + # Providing custom lists of permitted tags and attributes: + # + # <%= sanitize @comment.body, tags: %w(strong em a), attributes: %w(href) %> + # + # Providing a custom Rails::Html scrubber: + # + # class CommentScrubber < Rails::Html::PermitScrubber + # def initialize + # super + # self.tags = %w( form script comment blockquote ) + # self.attributes = %w( style ) + # end + # + # def skip_node?(node) + # node.text? + # end + # end + # + # <%= sanitize @comment.body, scrubber: CommentScrubber.new %> + # + # See {Rails HTML Sanitizer}[https://github.com/rails/rails-html-sanitizer] for + # documentation about Rails::Html scrubbers. + # + # Providing a custom Loofah::Scrubber: + # + # scrubber = Loofah::Scrubber.new do |node| + # node.remove if node.name == 'script' + # end + # + # <%= sanitize @comment.body, scrubber: scrubber %> + # + # See {Loofah's documentation}[https://github.com/flavorjones/loofah] for more + # information about defining custom Loofah::Scrubber objects. + # + # To set the default allowed tags or attributes across your application: + # + # # In config/application.rb + # config.action_view.sanitized_allowed_tags = ['strong', 'em', 'a'] + # config.action_view.sanitized_allowed_attributes = ['href', 'title'] + 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 +html+, including comments and special characters. + # + # strip_tags("Strip <i>these</i> tags!") + # # => Strip these tags! + # + # strip_tags("<b>Bold</b> no more! <a href='more.html'>See more here</a>...") + # # => Bold no more! See more here... + # + # strip_tags("<div id='top-bar'>Welcome to my website!</div>") + # # => Welcome to my website! + # + # strip_tags("> A quote from Smith & Wesson") + # # => > A quote from Smith & Wesson + def strip_tags(html) + self.class.full_sanitizer.sanitize(html) + end + + # Strips all link tags from +html+ leaving just the link text. + # + # strip_links('<a href="http://www.rubyonrails.org">Ruby on Rails</a>') + # # => Ruby on Rails + # + # strip_links('Please e-mail me at <a href="mailto:me@email.com">me@email.com</a>.') + # # => Please e-mail me at me@email.com. + # + # strip_links('Blog: <a href="http://www.myblog.com/" class="nav" target=\"_blank\">Visit</a>.') + # # => Blog: Visit. + # + # strip_links('<<a href="https://example.org">malformed & link</a>') + # # => <malformed & link + 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 compatibility and can be removed in Rails 6. + 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 + end + end + end +end |