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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
# <tt>:attributes</tt> or <tt>:tags</tt> 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 <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!
def strip_tags(html)
self.class.full_sanitizer.sanitize(html)
end
# Strips all link tags from +text+ 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.
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
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