discourse/lib/pretty_text.rb

713 lines
22 KiB
Ruby

# frozen_string_literal: true
require 'mini_racer'
require 'nokogiri'
require 'erb'
module PrettyText
DANGEROUS_BIDI_CHARACTERS = [
"\u202A",
"\u202B",
"\u202C",
"\u202D",
"\u202E",
"\u2066",
"\u2067",
"\u2068",
"\u2069",
].freeze
DANGEROUS_BIDI_REGEXP = Regexp.new(DANGEROUS_BIDI_CHARACTERS.join("|")).freeze
BLOCKED_HOTLINKED_SRC_ATTR = "data-blocked-hotlinked-src"
BLOCKED_HOTLINKED_SRCSET_ATTR = "data-blocked-hotlinked-srcset"
@mutex = Mutex.new
@ctx_init = Mutex.new
def self.app_root
Rails.root
end
def self.find_file(root, filename)
return filename if File.file?("#{root}#{filename}")
es6_name = "#{filename}.js.es6"
return es6_name if File.file?("#{root}#{es6_name}")
js_name = "#{filename}.js"
return js_name if File.file?("#{root}#{js_name}")
erb_name = "#{filename}.js.es6.erb"
return erb_name if File.file?("#{root}#{erb_name}")
erb_name = "#{filename}.js.erb"
return erb_name if File.file?("#{root}#{erb_name}")
end
def self.apply_es6_file(ctx, root_path, part_name)
filename = find_file(root_path, part_name)
if filename
source = File.read("#{root_path}#{filename}")
source = ERB.new(source).result(binding) if filename =~ /\.erb$/
transpiler = DiscourseJsProcessor::Transpiler.new
transpiled = transpiler.perform(source, "#{Rails.root}/app/assets/javascripts/", part_name)
ctx.eval(transpiled)
else
# Look for vendored stuff
vendor_root = "#{Rails.root}/vendor/assets/javascripts/"
filename = find_file(vendor_root, part_name)
if filename
ctx.eval(File.read("#{vendor_root}#{filename}"))
end
end
end
def self.ctx_load_directory(ctx, path)
root_path = "#{Rails.root}/app/assets/javascripts/"
Dir["#{root_path}#{path}/**/*"].sort.each do |f|
apply_es6_file(ctx, root_path, f.sub(root_path, '').sub(/\.js(.es6)?$/, ''))
end
end
def self.create_es6_context
ctx = MiniRacer::Context.new(timeout: 25000, ensure_gc_after_idle: 2000)
ctx.eval("window = {}; window.devicePixelRatio = 2;") # hack to make code think stuff is retina
ctx.attach("rails.logger.info", proc { |err| Rails.logger.info(err.to_s) })
ctx.attach("rails.logger.warn", proc { |err| Rails.logger.warn(err.to_s) })
ctx.attach("rails.logger.error", proc { |err| Rails.logger.error(err.to_s) })
ctx.eval <<~JS
console = {
prefix: "[PrettyText] ",
log: function(...args){ rails.logger.info(console.prefix + args.join(" ")); },
warn: function(...args){ rails.logger.warn(console.prefix + args.join(" ")); },
error: function(...args){ rails.logger.error(console.prefix + args.join(" ")); }
}
JS
ctx.eval("__PRETTY_TEXT = true")
PrettyText::Helpers.instance_methods.each do |method|
ctx.attach("__helpers.#{method}", PrettyText::Helpers.method(method))
end
root_path = "#{Rails.root}/app/assets/javascripts/"
ctx_load(ctx, "#{root_path}/mini-loader.js")
ctx_load(ctx, "#{root_path}/handlebars-shim.js")
ctx_load(ctx, "#{root_path}/node_modules/xss/dist/xss.js")
ctx.load("#{Rails.root}/lib/pretty_text/vendor-shims.js")
ctx_load_directory(ctx, "pretty-text/addon")
ctx_load_directory(ctx, "pretty-text/engines/discourse-markdown")
ctx_load(ctx, "#{root_path}/node_modules/markdown-it/dist/markdown-it.js")
apply_es6_file(ctx, root_path, "discourse-common/addon/lib/get-url")
apply_es6_file(ctx, root_path, "discourse-common/addon/lib/object")
apply_es6_file(ctx, root_path, "discourse-common/addon/lib/deprecated")
apply_es6_file(ctx, root_path, "discourse-common/addon/lib/escape")
apply_es6_file(ctx, root_path, "discourse-common/addon/utils/watched-words")
apply_es6_file(ctx, root_path, "discourse/app/lib/to-markdown")
apply_es6_file(ctx, root_path, "discourse/app/lib/utilities")
ctx.load("#{Rails.root}/lib/pretty_text/shims.js")
ctx.eval("__setUnicode(#{Emoji.unicode_replacements_json})")
to_load = []
DiscoursePluginRegistry.each_globbed_asset do |a|
to_load << a if File.file?(a) && a =~ /discourse-markdown/
end
to_load.uniq.each do |f|
if f =~ /^.+assets\/javascripts\//
root = Regexp.last_match[0]
apply_es6_file(ctx, root, f.sub(root, '').sub(/\.js(\.es6)?$/, ''))
end
end
DiscoursePluginRegistry.vendored_core_pretty_text.each do |vpt|
ctx.eval(File.read(vpt))
end
DiscoursePluginRegistry.vendored_pretty_text.each do |vpt|
ctx.eval(File.read(vpt))
end
ctx
end
def self.v8
return @ctx if @ctx
# ensure we only init one of these
@ctx_init.synchronize do
return @ctx if @ctx
@ctx = create_es6_context
end
@ctx
end
def self.reset_translations
v8.eval("__resetTranslationTree()")
end
def self.reset_context
@ctx_init.synchronize do
@ctx&.dispose
@ctx = nil
end
end
# Acceptable options:
#
# disable_emojis - Disables the emoji markdown engine.
# features - A hash where the key is the markdown feature name and the value is a boolean to enable/disable the markdown feature.
# The hash is merged into the default features set in pretty-text.js which can be used to add new features or disable existing features.
# features_override - An array of markdown feature names to override the default markdown feature set. Currently used by plugins to customize what features should be enabled
# when rendering markdown.
# markdown_it_rules - An array of markdown rule names which will be applied to the markdown-it engine. Currently used by plugins to customize what markdown-it rules should be
# enabled when rendering markdown.
# topic_id - Topic id for the post being cooked.
# user_id - User id for the post being cooked.
# force_quote_link - Always create the link to the quoted topic for [quote] bbcode. Normally this only happens
# if the topic_id provided is different from the [quote topic:X].
def self.markdown(text, opts = {})
# we use the exact same markdown converter as the client
# TODO: use the same extensions on both client and server (in particular the template for mentions)
baked = nil
text = text || ""
protect do
context = v8
custom_emoji = {}
Emoji.custom.map { |e| custom_emoji[e.name] = e.url }
# note, any additional options added to __optInput here must be
# also be added to the buildOptions function in pretty-text.js,
# otherwise they will be discarded
buffer = +<<~JS
__optInput = {};
__optInput.siteSettings = #{SiteSetting.client_settings_json};
#{"__optInput.disableEmojis = true" if opts[:disable_emojis]}
__paths = #{paths_json};
__optInput.getURL = __getURL;
#{"__optInput.features = #{opts[:features].to_json};" if opts[:features]}
#{"__optInput.featuresOverride = #{opts[:features_override].to_json};" if opts[:features_override]}
#{"__optInput.markdownItRules = #{opts[:markdown_it_rules].to_json};" if opts[:markdown_it_rules]}
__optInput.getCurrentUser = __getCurrentUser;
__optInput.lookupAvatar = __lookupAvatar;
__optInput.lookupPrimaryUserGroup = __lookupPrimaryUserGroup;
__optInput.formatUsername = __formatUsername;
__optInput.getTopicInfo = __getTopicInfo;
__optInput.categoryHashtagLookup = __categoryLookup;
__optInput.customEmoji = #{custom_emoji.to_json};
__optInput.customEmojiTranslation = #{Plugin::CustomEmoji.translations.to_json};
__optInput.emojiUnicodeReplacer = __emojiUnicodeReplacer;
__optInput.lookupUploadUrls = __lookupUploadUrls;
__optInput.censoredRegexp = #{WordWatcher.serializable_word_matcher_regexp(:censor).to_json };
__optInput.watchedWordsReplace = #{WordWatcher.word_matcher_regexps(:replace).to_json};
__optInput.watchedWordsLink = #{WordWatcher.word_matcher_regexps(:link).to_json};
__optInput.additionalOptions = #{Site.markdown_additional_options.to_json};
JS
if opts[:topic_id]
buffer << "__optInput.topicId = #{opts[:topic_id].to_i};\n"
end
if opts[:force_quote_link]
buffer << "__optInput.forceQuoteLink = #{opts[:force_quote_link]};\n"
end
if opts[:user_id]
buffer << "__optInput.userId = #{opts[:user_id].to_i};\n"
end
buffer << "__textOptions = __buildOptions(__optInput);\n"
buffer << ("__pt = new __PrettyText(__textOptions);")
# Be careful disabling sanitization. We allow for custom emails
if opts[:sanitize] == false
buffer << ('__pt.disableSanitizer();')
end
opts = context.eval(buffer)
DiscourseEvent.trigger(:markdown_context, context)
baked = context.eval("__pt.cook(#{text.inspect})")
end
baked
end
def self.paths_json
paths = {
baseUri: Discourse.base_path,
CDN: Rails.configuration.action_controller.asset_host,
}
if SiteSetting.Upload.enable_s3_uploads
if SiteSetting.Upload.s3_cdn_url.present?
paths[:S3CDN] = SiteSetting.Upload.s3_cdn_url
end
paths[:S3BaseUrl] = Discourse.store.absolute_base_url
end
paths.to_json
end
# leaving this here, cause it invokes v8, don't want to implement twice
def self.avatar_img(avatar_template, size)
protect do
v8.eval(<<~JS)
__paths = #{paths_json};
__utils.avatarImg({size: #{size.inspect}, avatarTemplate: #{avatar_template.inspect}}, __getURL);
JS
end
end
def self.unescape_emoji(title)
return title unless SiteSetting.enable_emoji? && title
set = SiteSetting.emoji_set.inspect
custom = Emoji.custom.map { |e| [e.name, e.url] }.to_h.to_json
protect do
v8.eval(<<~JS)
__paths = #{paths_json};
__performEmojiUnescape(#{title.inspect}, {
getURL: __getURL,
emojiSet: #{set},
emojiCDNUrl: "#{SiteSetting.external_emoji_url.blank? ? "" : SiteSetting.external_emoji_url}",
customEmoji: #{custom},
enableEmojiShortcuts: #{SiteSetting.enable_emoji_shortcuts},
inlineEmoji: #{SiteSetting.enable_inline_emoji_translation}
});
JS
end
end
def self.escape_emoji(title)
return unless title
replace_emoji_shortcuts = SiteSetting.enable_emoji && SiteSetting.enable_emoji_shortcuts
protect do
v8.eval(<<~JS)
__performEmojiEscape(#{title.inspect}, {
emojiShortcuts: #{replace_emoji_shortcuts},
inlineEmoji: #{SiteSetting.enable_inline_emoji_translation}
});
JS
end
end
def self.cook(text, opts = {})
options = opts.dup
working_text = text.dup
sanitized = markdown(working_text, options)
doc = Nokogiri::HTML5.fragment(sanitized)
add_nofollow = !options[:omit_nofollow] && SiteSetting.add_rel_nofollow_to_user_content
add_rel_attributes_to_user_content(doc, add_nofollow)
strip_hidden_unicode_bidirectional_characters(doc)
sanitize_hotlinked_media(doc)
if SiteSetting.enable_mentions
add_mentions(doc, user_id: opts[:user_id])
end
scrubber = Loofah::Scrubber.new do |node|
node.remove if node.name == 'script'
end
loofah_fragment = Loofah.fragment(doc.to_html)
loofah_fragment.scrub!(scrubber).to_html
end
def self.strip_hidden_unicode_bidirectional_characters(doc)
return if !DANGEROUS_BIDI_REGEXP.match?(doc.content)
doc.css("code,pre").each do |code_tag|
next if !DANGEROUS_BIDI_REGEXP.match?(code_tag.content)
DANGEROUS_BIDI_CHARACTERS.each do |bidi|
next if !code_tag.content.include?(bidi)
formatted = "&lt;U+#{bidi.ord.to_s(16).upcase}&gt;"
code_tag.inner_html = code_tag.inner_html.gsub(
bidi,
"<span class=\"bidi-warning\" title=\"#{I18n.t("post.hidden_bidi_character")}\">#{formatted}</span>"
)
end
end
end
def self.sanitize_hotlinked_media(doc)
return if !SiteSetting.block_hotlinked_media
allowed_pattern = allowed_src_pattern
doc.css("img[src], source[src], source[srcset], track[src]").each do |el|
if el["src"] && !el["src"].match?(allowed_pattern)
el[PrettyText::BLOCKED_HOTLINKED_SRC_ATTR] = el.delete("src")
end
if el["srcset"]
srcs = el["srcset"].split(',').map { |e| e.split(' ', 2)[0].presence }
if srcs.any? { |src| !src.match?(allowed_pattern) }
el[PrettyText::BLOCKED_HOTLINKED_SRCSET_ATTR] = el.delete("srcset")
end
end
end
end
def self.add_rel_attributes_to_user_content(doc, add_nofollow)
allowlist = []
domains = SiteSetting.exclude_rel_nofollow_domains
allowlist = domains.split('|') if domains.present?
site_uri = nil
doc.css("a").each do |l|
href = l["href"].to_s
l["rel"] = "noopener" if l["target"] == "_blank"
begin
uri = URI(UrlHelper.encode_component(href))
site_uri ||= URI(Discourse.base_url)
same_domain = !uri.host.present? ||
uri.host == site_uri.host ||
uri.host.ends_with?(".#{site_uri.host}") ||
allowlist.any? { |u| uri.host == u || uri.host.ends_with?(".#{u}") }
l["rel"] = "noopener nofollow ugc" if add_nofollow && !same_domain
rescue URI::Error
# add a nofollow anyway
l["rel"] = "noopener nofollow ugc"
end
end
end
class DetectedLink < Struct.new(:url, :is_quote); end
def self.extract_links(html)
links = []
doc = Nokogiri::HTML5.fragment(html)
# extract onebox links
doc.css("aside.onebox[data-onebox-src]").each { |onebox| links << DetectedLink.new(onebox["data-onebox-src"], false) }
# remove href inside quotes & oneboxes & elided part
doc.css("aside.quote a, aside.onebox a, .elided a").remove
# remove hotlinked images
doc.css("a.onebox > img").each { |img| img.parent.remove }
# extract all links
doc.css("a").each do |a|
if a["href"].present? && a["href"][0] != "#"
links << DetectedLink.new(a["href"], false)
end
end
# extract quotes
doc.css("aside.quote[data-topic]").each do |aside|
if aside["data-topic"].present?
url = +"/t/#{aside["data-topic"]}"
url << "/#{aside["data-post"]}" if aside["data-post"].present?
links << DetectedLink.new(url, true)
end
end
# extract Youtube links
doc.css("div[data-youtube-id]").each do |div|
if div["data-youtube-id"].present?
links << DetectedLink.new("https://www.youtube.com/watch?v=#{div['data-youtube-id']}", false)
end
end
links
end
def self.excerpt(html, max_length, options = {})
# TODO: properly fix this HACK in ExcerptParser without introducing XSS
doc = Nokogiri::HTML5.fragment(html)
DiscourseEvent.trigger(:reduce_excerpt, doc, options)
strip_image_wrapping(doc)
strip_oneboxed_media(doc)
html = doc.to_html
ExcerptParser.get_excerpt(html, max_length, options)
end
def self.strip_links(string)
return string if string.blank?
# If the user is not basic, strip links from their bio
fragment = Nokogiri::HTML5.fragment(string)
fragment.css('a').each { |a| a.replace(a.inner_html) }
fragment.to_html
end
def self.make_all_links_absolute(doc)
site_uri = nil
doc.css("a").each do |link|
href = link["href"].to_s
begin
uri = URI(href)
site_uri ||= URI(Discourse.base_url)
unless uri.host.present? || href.start_with?('mailto')
link["href"] = "#{site_uri}#{link['href']}"
end
rescue URI::Error
# leave it
end
end
end
def self.strip_image_wrapping(doc)
doc.css(".lightbox-wrapper .meta").remove
end
def self.strip_oneboxed_media(doc)
doc.css("audio").remove
doc.css(".video-onebox,video").remove
end
def self.convert_vimeo_iframes(doc)
doc.css("iframe[src*='player.vimeo.com']").each do |iframe|
if iframe["data-original-href"].present?
vimeo_url = UrlHelper.normalized_encode(iframe["data-original-href"])
else
vimeo_id = iframe['src'].split('/').last
vimeo_url = "https://vimeo.com/#{vimeo_id}"
end
iframe.replace Nokogiri::HTML5.fragment("<p><a href='#{vimeo_url}'>#{vimeo_url}</a></p>")
end
end
def self.strip_secure_media(doc)
# images inside a lightbox or other link
doc.css('a[href]').each do |a|
next if !Upload.secure_media_url?(a['href'])
non_image_media = %w(video audio).include?(a&.parent&.name)
target = non_image_media ? a.parent : a
next if target.to_s.include?('stripped-secure-view-media')
next if a.css('img[src]').empty? && !non_image_media
if a.classes.include?('lightbox')
img = a.css('img[src]').first
srcset = img&.attributes['srcset']&.value
if srcset
# if available, use the first image from the srcset here
# so we get the optimized image instead of the possibly huge original
url = srcset.split(',').first
else
url = img['src']
end
a.add_next_sibling secure_media_placeholder(doc, url, width: img['width'], height: img['height'])
a.remove
else
width = non_image_media ? nil : a.at_css('img').attr('width')
height = non_image_media ? nil : a.at_css('img').attr('height')
target.add_next_sibling secure_media_placeholder(doc, a['href'], width: width, height: height)
target.remove
end
end
# images by themselves or inside a onebox
doc.css('img[src]').each do |img|
url = if img.parent.classes.include?("aspect-image") && img.attributes["srcset"].present?
# we are using the first image from the srcset here so we get the
# optimized image instead of the original, because an optimized
# image may be used for the onebox thumbnail
srcset = img.attributes["srcset"].value
srcset.split(",").first
else
img['src']
end
width = img['width']
height = img['height']
onebox_type = nil
if img.ancestors.css(".onebox-body").any?
if img.classes.include?("onebox-avatar-inline")
onebox_type = "avatar-inline"
else
onebox_type = "thumbnail"
end
end
# we always want this to be tiny and without any special styles
if img.classes.include?('site-icon')
onebox_type = nil
width = 16
height = 16
end
if Upload.secure_media_url?(url)
img.add_next_sibling secure_media_placeholder(doc, url, onebox_type: onebox_type, width: width, height: height)
img.remove
end
end
end
def self.secure_media_placeholder(doc, url, onebox_type: false, width: nil, height: nil)
data_width = width ? "data-width=#{width}" : ''
data_height = height ? "data-height=#{height}" : ''
data_onebox_type = onebox_type ? "data-onebox-type='#{onebox_type}'" : ''
<<~HTML
<div class="secure-media-notice" data-stripped-secure-media="#{url}" #{data_onebox_type} #{data_width} #{data_height}>
#{I18n.t('emails.secure_media_placeholder')} <a class='stripped-secure-view-media' href="#{url}">#{I18n.t("emails.view_redacted_media")}</a>.
</div>
HTML
end
def self.format_for_email(html, post = nil)
doc = Nokogiri::HTML5.fragment(html)
DiscourseEvent.trigger(:reduce_cooked, doc, post)
strip_secure_media(doc) if post&.with_secure_media?
strip_image_wrapping(doc)
convert_vimeo_iframes(doc)
make_all_links_absolute(doc)
doc.to_html
end
protected
class JavaScriptError < StandardError
attr_accessor :message, :backtrace
def initialize(message, backtrace)
@message = message
@backtrace = backtrace
end
end
def self.protect
rval = nil
@mutex.synchronize do
rval = yield
end
rval
end
def self.ctx_load(ctx, *files)
files.each do |file|
ctx.load(app_root + file)
end
end
private
USER_TYPE ||= 'user'
GROUP_TYPE ||= 'group'
GROUP_MENTIONABLE_TYPE ||= 'group-mentionable'
def self.add_mentions(doc, user_id: nil)
elements = doc.css("span.mention")
names = elements.map { |element| element.text[1..-1] }
mentions = lookup_mentions(names, user_id: user_id)
elements.each do |element|
name = element.text[1..-1]
name.downcase!
if type = mentions[name]
element.name = 'a'
element.children = PrettyText::Helpers.format_username(
element.children.text
)
case type
when USER_TYPE
element['href'] = "#{Discourse.base_path}/u/#{UrlHelper.encode_component(name)}"
when GROUP_MENTIONABLE_TYPE
element['class'] = 'mention-group notify'
element['href'] = "#{Discourse.base_path}/groups/#{UrlHelper.encode_component(name)}"
when GROUP_TYPE
element['class'] = 'mention-group'
element['href'] = "#{Discourse.base_path}/groups/#{UrlHelper.encode_component(name)}"
end
end
end
end
def self.lookup_mentions(names, user_id: nil)
return {} if names.blank?
sql = <<~SQL
(
SELECT
:user_type AS type,
username_lower AS name
FROM users
WHERE username_lower IN (:names) AND staged = false
)
UNION
(
SELECT
:group_type AS type,
lower(name) AS name
FROM groups
)
UNION
(
SELECT
:group_mentionable_type AS type,
lower(name) AS name
FROM groups
WHERE lower(name) IN (:names) AND (#{Group.mentionable_sql_clause(include_public: false)})
)
ORDER BY type
SQL
user = User.find_by(id: user_id)
names.each(&:downcase!)
results = DB.query(sql,
names: names,
user_type: USER_TYPE,
group_type: GROUP_TYPE,
group_mentionable_type: GROUP_MENTIONABLE_TYPE,
levels: Group.alias_levels(user),
user_id: user_id
)
mentions = {}
results.each { |result| mentions[result.name] = result.type }
mentions
end
def self.allowed_src_pattern
allowed_src_prefixes = [
Discourse.base_path,
Discourse.base_url,
GlobalSetting.s3_cdn_url,
GlobalSetting.cdn_url,
SiteSetting.external_emoji_url.presence,
*SiteSetting.block_hotlinked_media_exceptions.split("|")
]
patterns = allowed_src_prefixes.compact.map do |url|
pattern = Regexp.escape(url)
# If 'https://example.com' is allowed, ensure 'https://example.com.blah.com' is not
pattern += '(?:/|\z)' if !pattern.ends_with?("\/")
pattern
end
/\A(data:|#{patterns.join("|")})/
end
end