discourse/lib/pretty_text.rb
Martin Brennan 0b3cf83e3c
FIX: Do not cook icon with hashtags (#21676)
This commit makes some fundamental changes to how hashtag cooking and
icon generation works in the new experimental hashtag autocomplete mode.
Previously we cooked the appropriate SVG icon with the cooked hashtag,
though this has proved inflexible especially for theming purposes.

Instead, we now cook a data-ID attribute with the hashtag and add a new
span as an icon placeholder. This is replaced on the client side with an
icon (or a square span in the case of categories) on the client side via
the decorateCooked API for posts and chat messages.

This client side logic uses the generated hashtag, category, and channel
CSS classes added in a previous commit.

This is missing changes to the sidebar to use the new generated CSS
classes and also colors and the split square for categories in the
hashtag autocomplete menu -- I will tackle this in a separate PR so it
is clearer.
2023-05-23 09:33:55 +02:00

774 lines
25 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\z/
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)
ctx.eval(File.read("#{vendor_root}#{filename}")) if filename
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)?\z/, ""))
end
end
def self.create_es6_context
ctx = MiniRacer::Context.new(timeout: 25_000, 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}/node_modules/loader.js/dist/loader/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 =~ %r{\A.+assets/javascripts/}
root = Regexp.last_match[0]
apply_es6_file(ctx, root, f.sub(root, "").sub(/\.js(\.es6)?\z/, ""))
end
end
DiscoursePluginRegistry.vendored_core_pretty_text.each { |vpt| ctx.eval(File.read(vpt)) }
DiscoursePluginRegistry.vendored_pretty_text.each { |vpt| ctx.eval(File.read(vpt)) }
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].
# hashtag_context - Defaults to "topic-composer" if not supplied. Controls the order of #hashtag lookup results
# based on registered hashtag contexts from the `#register_hashtag_search_param` plugin API
# method.
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.hashtagLookup = __hashtagLookup;
__optInput.customEmoji = #{custom_emoji.to_json};
__optInput.customEmojiTranslation = #{Plugin::CustomEmoji.translations.to_json};
__optInput.emojiUnicodeReplacer = __emojiUnicodeReplacer;
__optInput.emojiDenyList = #{Emoji.denied.to_json};
__optInput.lookupUploadUrls = __lookupUploadUrls;
__optInput.censoredRegexp = #{WordWatcher.serializable_word_matcher_regexp(:censor, engine: :js).to_json};
__optInput.watchedWordsReplace = #{WordWatcher.word_matcher_regexps(:replace, engine: :js).to_json};
__optInput.watchedWordsLink = #{WordWatcher.word_matcher_regexps(:link, engine: :js).to_json};
__optInput.additionalOptions = #{Site.markdown_additional_options.to_json};
JS
buffer << "__optInput.topicId = #{opts[:topic_id].to_i};\n" if opts[:topic_id]
if opts[:force_quote_link]
buffer << "__optInput.forceQuoteLink = #{opts[:force_quote_link]};\n"
end
buffer << "__optInput.userId = #{opts[:user_id].to_i};\n" if opts[:user_id]
opts[:hashtag_context] = opts[:hashtag_context] || "topic-composer"
hashtag_types_as_js =
HashtagAutocompleteService
.ordered_types_for_context(opts[:hashtag_context])
.map { |t| "'#{t}'" }
.join(",")
buffer << "__optInput.hashtagTypesInPriorityOrder = [#{hashtag_types_as_js}];\n"
buffer << "__optInput.hashtagIcons = #{HashtagAutocompleteService.data_source_icon_map.to_json};\n"
buffer << "__textOptions = __buildOptions(__optInput);\n"
buffer << ("__pt = new __PrettyText(__textOptions);")
# Be careful disabling sanitization. We allow for custom emails
buffer << ("__pt.disableSanitizer();") if opts[:sanitize] == false
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
paths[:S3CDN] = SiteSetting.Upload.s3_cdn_url if SiteSetting.Upload.s3_cdn_url.present?
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 { v8.eval(<<~JS) }
__paths = #{paths_json};
__utils.avatarImg({size: #{size.inspect}, avatarTemplate: #{avatar_template.inspect}}, __getURL);
JS
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 { 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
def self.escape_emoji(title)
return unless title
replace_emoji_shortcuts = SiteSetting.enable_emoji && SiteSetting.enable_emoji_shortcuts
protect { v8.eval(<<~JS) }
__performEmojiEscape(#{title.inspect}, {
emojiShortcuts: #{replace_emoji_shortcuts},
inlineEmoji: #{SiteSetting.enable_inline_emoji_translation}
});
JS
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)
add_mentions(doc, user_id: opts[:user_id]) if SiteSetting.enable_mentions
scrubber = Loofah::Scrubber.new { |node| node.remove if node.name == "script" }
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|
links << DetectedLink.new(a["href"], false) if a["href"].present? && a["href"][0] != "#"
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-video-id]")
.each do |div|
if div["data-video-id"].present? && div["data-provider-name"].present?
base_url =
case div["data-provider-name"]
when "youtube"
"https://www.youtube.com/watch?v="
when "vimeo"
"https://vimeo.com/"
when "tiktok"
"https://m.tiktok.com/v/"
end
links << DetectedLink.new(base_url + div["data-video-id"], false)
end
end
links
end
def self.extract_mentions(cooked)
mentions =
cooked
.css(".mention, .mention-group")
.map do |e|
if (name = e.inner_text)
name = name[1..-1]
name = User.normalize_username(name)
name
end
end
mentions.compact!
mentions.uniq!
mentions
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)
if SiteSetting.enable_experimental_hashtag_autocomplete && options[:plain_hashtags]
convert_hashtag_links_to_plaintext(doc)
end
html = doc.to_html
ExcerptParser.get_excerpt(html, max_length, options)
end
def self.convert_hashtag_links_to_plaintext(doc)
doc
.css("a.hashtag-cooked")
.each { |hashtag| hashtag.replace("##{hashtag.attributes["data-slug"]}") }
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.sub("?h=", "/")
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_uploads(doc)
# images inside a lightbox or other link
doc
.css("a[href]")
.each do |a|
next if !Upload.secure_uploads_url?(a["href"])
non_image_media = %w[video audio].include?(a&.parent&.name)
target = non_image_media ? a.parent : a
if target.to_s.include?("stripped-secure-view-media") ||
target.to_s.include?("stripped-secure-view-upload")
next
end
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_uploads_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_uploads_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_uploads_url?(url)
img.add_next_sibling secure_uploads_placeholder(
doc,
url,
onebox_type: onebox_type,
width: width,
height: height,
)
img.remove
end
end
end
def self.secure_uploads_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-upload-notice" data-stripped-secure-upload="#{url}" #{data_onebox_type} #{data_width} #{data_height}>
#{I18n.t("emails.secure_uploads_placeholder")} <a class='stripped-secure-view-upload' 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_uploads(doc) if post&.with_secure_uploads?
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 { rval = yield }
rval
end
def self.ctx_load(ctx, *files)
files.each { |file| ctx.load(app_root + file) }
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