Action View Sanitize 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.

Methods

Instance Public methods

sanitize(html, options = {})

Sanitizes HTML input, stripping all but known-safe tags and attributes.

It also strips href / src attributes with unsafe protocols like javascript:, while also protecting against attempts to use Unicode, ASCII, and hex character references to work around these protocol filters.

The default sanitizer is Rails::HTML5::SafeListSanitizer. See Rails HTML Sanitizers 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

:tags

An array of allowed tags.

:attributes

An array of allowed attributes.

:scrubber

A Rails::HTML scrubber or Loofah::Scrubber 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 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 for more information about defining custom Loofah::Scrubber objects.

Global Configuration

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']

The default, starting in Rails 7.1, is to use an HTML5 parser for sanitization (if it is available, see NOTE below). If you wish to revert back to the previous HTML4 behavior, you can do so by setting the following in your application configuration:

# In config/application.rb
config.action_view.sanitizer_vendor = Rails::HTML4::Sanitizer

Or, if you’re upgrading from a previous version of Rails and wish to opt into the HTML5 behavior:

# In config/application.rb
config.action_view.sanitizer_vendor = Rails::HTML5::Sanitizer

NOTE: Rails::HTML5::Sanitizer is not supported on JRuby, so on JRuby platforms Rails will fall back to using Rails::HTML4::Sanitizer.

📝 Source code 
# File actionview/lib/action_view/helpers/sanitize_helper.rb, line 111
      def sanitize(html, options = {})
        self.class.safe_list_sanitizer.sanitize(html, options)&.html_safe
      end
🔎 See on GitHub

sanitize_css(style)

Sanitizes a block of CSS code. Used by sanitize when it comes across a style attribute.

📝 Source code 
# File actionview/lib/action_view/helpers/sanitize_helper.rb, line 116
      def sanitize_css(style)
        self.class.safe_list_sanitizer.sanitize_css(style)
      end
🔎 See on GitHub

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>')
# => &lt;malformed &amp; link
📝 Source code 
# File actionview/lib/action_view/helpers/sanitize_helper.rb, line 150
      def strip_links(html)
        self.class.link_sanitizer.sanitize(html)
      end
🔎 See on GitHub

strip_tags(html)

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")
# => &gt; A quote from Smith &amp; Wesson
📝 Source code 
# File actionview/lib/action_view/helpers/sanitize_helper.rb, line 133
      def strip_tags(html)
        self.class.full_sanitizer.sanitize(html)&.html_safe
      end
🔎 See on GitHub