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# frozen_string_literal: true
class Sanitize
extend UrlHelper
module Config
HTTP_PROTOCOLS ||= ['http', 'https', 'dat', 'dweb', 'ipfs', 'ipns', 'ssb', 'gopher', :relative].freeze
MEDIA_EXTENSIONS ||= %w(png apng jpg jpe jpeg mpg mpeg mpeg4 mp4 mp3 aac ogg oga ogv qt gif)
CLASS_WHITELIST_TRANSFORMER = lambda do |env|
node = env[:node]
class_list = node['class']&.split(/[\t\n\f\r ]/)
return unless class_list
class_list.keep_if do |e|
next true if e =~ /^(h|p|u|dt|e)-/ # microformats classes
next true if e =~ /^(mention|hashtag)$/ # semantic classes
next true if e =~ /^(ellipsis|invisible)$/ # link formatting classes
next true if e =~ /^bbcode__([a-z1-6\-]+)$/ # bbcode
next true if e == 'signature'
end
node['class'] = class_list.join(' ')
end
ANCHOR_SANITIZER = lambda do |env|
return unless env[:node_name] == 'a'
node = env[:node]
return if node['href'].blank? || node.text.blank?
class_list = node['class']&.split(/[\t\n\f\r ]/)
return if class_list && (class_list.include?('mention') || class_list.include?('hashtag'))
# href matches link text verbatim?
href = node['href']
return if href == node.text.strip
# href matches link text with sanitized query string?
text = Sanitize::sanitize_query_string(node.text.strip)
return if text.blank?
if href == text
node.inner_html = "\u2728 #{node.inner_html}"
return
end
# strip ellipse & replace keyword search obscuring
text = text.sub(/ *(?:\u2026|\.\.\.)\Z/, '').gsub(/ dot /i, '.').gsub(/[\u200b-\u200d\ufeff\u200e\u200f]/, '')
# href now matches text without obscuring?
if href == text
node.inner_html = "\u2728 #{node.inner_html}"
return
end
# try to detect pseudomentions
if text.start_with?('@') && text.match?(Account::MENTION_RE)
username, domain = text[1..-1].split('@', 2)
return if href == "https://#{domain}/@#{username}"
return if href == "https://#{domain}/#{username}"
return if href == "https://#{username}.#{domain}"
return if href == "https://#{domain}/users/#{username}"
return if href == "https://#{domain}/user/#{username}"
end
# try to detect filenames
href_filename = '/'.in?(href) ? href.rpartition('/')[2] : nil
unless href_filename.blank? || !('.'.in?(href_filename))
# possibly linked media?
ext = href_filename.rpartition('.')[2]
if ext.downcase.in?(MEDIA_EXTENSIONS)
node.inner_html = "\xf0\x9f\x96\xbc\xef\xb8\x8f #{node.inner_html}"
return
end
end
# grab first url from link text
first_url = text.scan(/[\w\-]+\.[\w\-]+(?:\.[\w\-]+)*\S*/).first
return if first_url.nil?
# strip trailing punctuation
text.sub!(/\p{Punct}+\Z/, '')
# href starts with link text?
return if href.start_with?(text)
# split href into parts & grab shortened href
uri = Addressable::URI.parse(href)
short_href = "#{uri.host}#{uri.path}"
normalized_short_href = "#{uri.normalized_host}#{uri.normalized_path}"
# shortened href starts with link text?
return if short_href.start_with?(text) || normalized_short_href.start_with?(text)
# first domain in link text (if there is one) matches href domain?
return if short_href == first_url || normalized_short_href == first_url
# possibly misleading link text
node.inner_html = "\u26a0\ufe0f #{node.inner_html}"
rescue Addressable::URI::InvalidURIError, IDN::Idna::IdnaError
# strip malformed links
node = env[:node]
node['href'] = '#'
node.children.remove
node.inner_html = "\u274c #{node.inner_html}"
end
QUERY_STRING_SANITIZER = lambda do |env|
return unless %w(a blockquote embed iframe source).include?(env[:node_name])
node = env[:node]
['href', 'src', 'cite'].each do |attr|
next if node[attr].blank?
url = Sanitize::sanitize_query_string(node[attr])
next if url.blank?
node[attr] = url
end
end
MASTODON_STRICT ||= freeze_config(
elements: %w(p br span a abbr del pre sub sup blockquote code b strong u i s em h1 h2 h3 h4 h5 h6 ul ol li hr),
attributes: {
'a' => %w(href rel class title alt),
'span' => %w(class),
'abbr' => %w(title),
'blockquote' => %w(cite),
'p' => %w(class),
:all => %w(aria-hidden aria-label lang),
},
add_attributes: {
'a' => {
'rel' => 'nofollow noopener',
'target' => '_blank',
},
},
protocols: {
'a' => { 'href' => HTTP_PROTOCOLS },
'blockquote' => { 'cite' => HTTP_PROTOCOLS },
},
transformers: [
CLASS_WHITELIST_TRANSFORMER,
QUERY_STRING_SANITIZER,
ANCHOR_SANITIZER
]
)
MASTODON_OEMBED ||= freeze_config merge(
RELAXED,
elements: RELAXED[:elements] + %w(audio embed iframe source video),
attributes: merge(
RELAXED[:attributes],
'audio' => %w(controls),
'embed' => %w(height src type width),
'iframe' => %w(allowfullscreen frameborder height scrolling src width),
'source' => %w(src type),
'video' => %w(controls height loop width),
'div' => [:data]
),
protocols: merge(
RELAXED[:protocols],
'embed' => { 'src' => HTTP_PROTOCOLS },
'iframe' => { 'src' => HTTP_PROTOCOLS },
'source' => { 'src' => HTTP_PROTOCOLS }
),
transformers: [QUERY_STRING_SANITIZER]
)
end
end
|
