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# frozen_string_literal: true
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::SafeListSanitizer. 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.safe_list_sanitizer.sanitize(html, options)&.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.safe_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, :safe_list_sanitizer
def sanitized_allowed_tags
safe_list_sanitizer.allowed_tags
end
def sanitized_allowed_attributes
safe_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 ||= Rails::Html::Sanitizer.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 ||= Rails::Html::Sanitizer.link_sanitizer.new
end
# Gets the Rails::Html::SafeListSanitizer instance used by sanitize and +sanitize_css+.
# Replace with any object that responds to +sanitize+.
#
# class Application < Rails::Application
# config.action_view.safe_list_sanitizer = MySpecialSanitizer.new
# end
def safe_list_sanitizer
@safe_list_sanitizer ||= Rails::Html::Sanitizer.safe_list_sanitizer.new
end
end
end
end
end
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