gab-social/app/lib/formatter.rb
mgabdev 788150536d Updated markdown parsing in backend
• Updated:
- markdown parsing in backend
2020-06-19 21:51:08 -04:00

449 lines
13 KiB
Ruby

# frozen_string_literal: true
require 'singleton'
require_relative './sanitize_config'
class HTMLRenderer < Redcarpet::Render::HTML
def block_code(code, language)
"<pre><code>#{encode(code).gsub("\n", "<br/>")}</code></pre>"
end
def block_quote(quote)
"<blockquote>#{quote}</blockquote>"
end
def codespan(code)
"<code>#{encode(code).gsub("\n", "<br/>")}</code>"
end
def double_emphasis(text)
"<strong>#{text}</strong>"
end
def emphasis(text)
"<em>#{text}</em>"
end
def header(text, header_level)
"<h1>#{text}</h1>"
end
def paragraph(text)
"<p>#{text}</p>"
end
def triple_emphasis(text)
"<b><em>#{text}</em></b>"
end
def strikethrough(text)
"<del>#{text}</del>"
end
def underline(text)
"<u>#{text}</u>"
end
def list(contents, list_type)
if list_type == :ordered
"<ol>#{contents}</ol>"
elsif list_type == :unordered
"<ul>#{contents}</ul>"
else
content
end
end
def list_item(text, list_type)
"<li>#{text}</li>"
end
def autolink(link, link_type)
return link if link_type == :email
Formatter.instance.link_url(link)
end
private
def html_entities
@html_entities ||= HTMLEntities.new
end
def encode(html)
html_entities.encode(html)
end
end
class Formatter
include Singleton
include RoutingHelper
include ActionView::Helpers::TextHelper
def format(status, **options)
if options[:use_markdown]
raw_content = status.markdown
return '' if raw_content.blank?
else
raw_content = status.text
end
raw_content = ActionController::Base.helpers.strip_tags(raw_content) if status.id <= 11063737261633602 # #TODO: Migration fix
if status.reblog?
status = status.proper
end
if options[:inline_poll_options] && status.preloadable_poll
raw_content = raw_content + "\n\n" + status.preloadable_poll.options.map { |title| "[ ] #{title}" }.join("\n")
end
return '' if raw_content.blank?
unless status.local?
html = reformat(raw_content)
html = encode_custom_emojis(html, status.emojis, options[:autoplay]) if options[:custom_emojify]
return html.html_safe # rubocop:disable Rails/OutputSafety
end
linkable_accounts = status.active_mentions.map(&:account)
linkable_accounts << status.account
html = raw_content
html = format_markdown(html) if options[:use_markdown]
html = encode_and_link_urls(html, linkable_accounts, keep_html: options[:use_markdown])
html = reformat(html, true) unless options[:use_markdown]
html = encode_custom_emojis(html, status.emojis, options[:autoplay]) if options[:custom_emojify]
unless options[:use_markdown]
html = html.gsub(/(?:\n\r?|\r\n?)/, '<br />')
html = html.delete("\n")
end
html.html_safe # rubocop:disable Rails/OutputSafety
html
end
def format_markdown(html)
html = markdown_formatter.render(html)
html = html.gsub(/\n/, '<br />')
html.delete("\r").delete("\n")
html
end
def reformat(html, outgoing = false)
sanitize(html, Sanitize::Config::GABSOCIAL_STRICT.merge(outgoing: outgoing))
rescue ArgumentError
''
end
def plaintext(status)
return status.text if status.local?
text = status.text.gsub(/(<br \/>|<br>|<\/p>)+/) { |match| "#{match}\n" }
strip_tags(text)
end
def simplified_format(account, **options)
html = account.local? ? linkify(account.note) : reformat(account.note)
html = encode_custom_emojis(html, account.emojis, options[:autoplay]) if options[:custom_emojify]
html.html_safe # rubocop:disable Rails/OutputSafety
end
def sanitize(html, config)
Sanitize.fragment(html, config)
end
def format_spoiler(status, **options)
html = encode(status.spoiler_text)
html = encode_custom_emojis(html, status.emojis, options[:autoplay])
html.html_safe # rubocop:disable Rails/OutputSafety
end
def format_poll_option(status, option, **options)
html = encode(option.title)
html = encode_custom_emojis(html, status.emojis, options[:autoplay])
html.html_safe # rubocop:disable Rails/OutputSafety
end
def format_display_name(account, **options)
html = encode(account.display_name.presence || account.username)
html = encode_custom_emojis(html, account.emojis, options[:autoplay]) if options[:custom_emojify]
html.html_safe # rubocop:disable Rails/OutputSafety
end
def format_field(account, str, **options)
html = account.local? ? encode_and_link_urls(str, me: true) : reformat(str)
html = encode_custom_emojis(html, account.emojis, options[:autoplay]) if options[:custom_emojify]
html.html_safe # rubocop:disable Rails/OutputSafety
end
def linkify(text)
html = encode_and_link_urls(text)
html = simple_format(html, {}, sanitize: false)
html = html.delete("\n")
html.html_safe # rubocop:disable Rails/OutputSafety
end
def link_url(url)
"<a href=\"#{encode(url)}\" target=\"blank\" rel=\"nofollow noopener noreferrer\">#{link_html(url)}</a>"
end
private
def markdown_formatter
extensions = {
autolink: false,
no_intra_emphasis: true,
fenced_code_blocks: true,
disable_indented_code_blocks: true,
strikethrough: true,
lax_spacing: true,
space_after_headers: true,
superscript: false,
underline: true,
highlight: false,
footnotes: false,
}
renderer = HTMLRenderer.new({
filter_html: false,
escape_html: false,
no_images: true,
no_styles: true,
safe_links_only: false,
hard_wrap: false,
no_links: true,
with_toc_data: false,
prettify: false,
link_attributes: nil
})
Redcarpet::Markdown.new(renderer, extensions)
end
def html_entities
@html_entities ||= HTMLEntities.new
end
def encode(html)
html_entities.encode(html)
end
def encode_and_link_urls(html, accounts = nil, options = {})
entities = utf8_friendly_extractor(html, extract_url_without_protocol: false)
if accounts.is_a?(Hash)
options = accounts
accounts = nil
end
rewrite(html.dup, entities, options[:keep_html]) do |entity|
if entity[:url]
link_to_url(entity, options)
elsif entity[:hashtag]
link_to_hashtag(entity)
elsif entity[:screen_name]
link_to_mention(entity, accounts)
end
end
end
def count_tag_nesting(tag)
if tag[1] == '/' then -1
elsif tag[-2] == '/' then 0
else 1
end
end
def encode_custom_emojis(html, emojis, animate = false)
return html if emojis.empty?
emoji_map = if animate
emojis.each_with_object({}) { |e, h| h[e.shortcode] = full_asset_url(e.image.url) }
else
emojis.each_with_object({}) { |e, h| h[e.shortcode] = full_asset_url(e.image.url(:static)) }
end
i = -1
tag_open_index = nil
inside_shortname = false
shortname_start_index = -1
invisible_depth = 0
while i + 1 < html.size
i += 1
if invisible_depth.zero? && inside_shortname && html[i] == ':'
shortcode = html[shortname_start_index + 1..i - 1]
emoji = emoji_map[shortcode]
if emoji
replacement = "<img draggable=\"false\" class=\"emojione\" alt=\":#{encode(shortcode)}:\" title=\":#{encode(shortcode)}:\" src=\"#{encode(emoji)}\" />"
before_html = shortname_start_index.positive? ? html[0..shortname_start_index - 1] : ''
html = before_html + replacement + html[i + 1..-1]
i += replacement.size - (shortcode.size + 2) - 1
else
i -= 1
end
inside_shortname = false
elsif tag_open_index && html[i] == '>'
tag = html[tag_open_index..i]
tag_open_index = nil
if invisible_depth.positive?
invisible_depth += count_tag_nesting(tag)
elsif tag == '<span class="invisible">'
invisible_depth = 1
end
elsif html[i] == '<'
tag_open_index = i
inside_shortname = false
elsif !tag_open_index && html[i] == ':'
inside_shortname = true
shortname_start_index = i
end
end
html
end
def rewrite(text, entities, keep_html = false)
text = text.to_s
# Sort by start index
entities = entities.sort_by do |entity|
indices = entity.respond_to?(:indices) ? entity.indices : entity[:indices]
indices.first
end
result = []
last_index = entities.reduce(0) do |index, entity|
indices = entity.respond_to?(:indices) ? entity.indices : entity[:indices]
result << (keep_html ? text[index...indices.first] : encode(text[index...indices.first]))
result << yield(entity)
indices.last
end
result << (keep_html ? text[last_index..-1] : encode(text[last_index..-1]))
result.flatten.join
end
UNICODE_ESCAPE_BLACKLIST_RE = /\p{Z}|\p{P}/
def utf8_friendly_extractor(text, options = {})
old_to_new_index = [0]
escaped = text.chars.map do |c|
output = begin
if c.ord.to_s(16).length > 2 && UNICODE_ESCAPE_BLACKLIST_RE.match(c).nil?
CGI.escape(c)
else
c
end
end
old_to_new_index << old_to_new_index.last + output.length
output
end.join
# Note: I couldn't obtain list_slug with @user/list-name format
# for mention so this requires additional check
special = Extractor.extract_urls_with_indices(escaped, options).map do |extract|
new_indices = [
old_to_new_index.find_index(extract[:indices].first),
old_to_new_index.find_index(extract[:indices].last),
]
next extract.merge(
indices: new_indices,
url: text[new_indices.first..new_indices.last - 1]
)
end
standard = Extractor.extract_entities_with_indices(text, options)
Extractor.remove_overlapping_entities(special + standard)
end
def html_friendly_extractor(html, options = {})
gaps = []
total_offset = 0
escaped = html.gsub(/<[^>]*>|&#[0-9]+;/) do |match|
total_offset += match.length - 1
end_offset = Regexp.last_match.end(0)
gaps << [end_offset - total_offset, total_offset]
"\u200b"
end
entities = Extractor.extract_hashtags_with_indices(escaped, :check_url_overlap => false) +
Extractor.extract_mentions_or_lists_with_indices(escaped)
Extractor.remove_overlapping_entities(entities).map do |extract|
pos = extract[:indices].first
offset_idx = gaps.rindex { |gap| gap.first <= pos }
offset = offset_idx.nil? ? 0 : gaps[offset_idx].last
next extract.merge(
:indices => [extract[:indices].first + offset, extract[:indices].last + offset]
)
end
end
def link_to_url(entity, options = {})
url = Addressable::URI.parse(entity[:url])
html_attrs = { target: '_blank', rel: 'nofollow noopener noreferrer' }
html_attrs[:rel] = "me #{html_attrs[:rel]}" if options[:me]
Twitter::Autolink.send(:link_to_text, entity, link_html(entity[:url]), url, html_attrs)
rescue Addressable::URI::InvalidURIError, IDN::Idna::IdnaError
encode(entity[:url])
end
def link_to_mention(entity, linkable_accounts)
acct = entity[:screen_name]
return link_to_account(acct) unless linkable_accounts
account = linkable_accounts.find { |item| TagManager.instance.same_acct?(item.acct, acct) }
account ? mention_html(account) : "@#{encode(acct)}"
end
def link_to_account(acct)
username, domain = acct.split('@')
domain = nil if TagManager.instance.local_domain?(domain)
account = EntityCache.instance.mention(username, domain)
account ? mention_html(account) : "@#{encode(acct)}"
end
def link_to_hashtag(entity)
hashtag_html(entity[:hashtag])
end
def link_html(url)
url = Addressable::URI.parse(url).to_s
prefix = url.match(/\Ahttps?:\/\/(www\.)?/).to_s
text = url[prefix.length, 45]
suffix = url[prefix.length + 45..-1]
cutoff = url[prefix.length..-1].length > 45
"<span aria-hidden=\"true\" class=\"invisible\">#{encode(prefix)}</span>#{encode(text)}<span aria-hidden=\"true\" class=\"invisible\">#{encode(suffix)}</span>" + (cutoff ? "<span aria-hidden=\"true\" class=\"ellipsis\"></span>" : "")
end
def hashtag_html(tag)
"<a data-focusable=\"true\" role=\"link\" href=\"#{encode(tag_url(tag.downcase))}\" class=\"mention hashtag\" rel=\"tag\">##{encode(tag)}</a>"
end
def mention_html(account)
return "<span>@#{encode(account.acct)}</span>" unless account.local?
"<a data-focusable=\"true\" role=\"link\" href=\"#{encode(TagManager.instance.url_for(account))}\" class=\"u-url mention\">@#{encode(account.acct)}</a>"
end
end