mastodon/app/lib/advanced_text_formatter.rb

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# frozen_string_literal: true
class AdvancedTextFormatter < TextFormatter
class HTMLRenderer < Redcarpet::Render::HTML
def initialize(options, &block)
super(options)
@format_link = block
end
def block_code(code, _language)
<<~HTML.squish
<pre><code>#{h(code).gsub("\n", '<br/>')}</code></pre>
HTML
end
def autolink(link, link_type)
return link if link_type == :email
@format_link.call(link)
end
end
# @param [String] text
# @param [Hash] options
# @option options [Boolean] :multiline
# @option options [Boolean] :with_domains
# @option options [Boolean] :with_rel_me
# @option options [Array<Account>] :preloaded_accounts
# @option options [String] :content_type
def initialize(text, options = {})
content_type = options.delete(:content_type)
super(text, options)
@text = format_markdown(text) if content_type == 'text/markdown'
end
# Differs from TextFormatter by not messing with newline after parsing
def to_s
return ''.html_safe if text.blank?
html = rewrite do |entity|
if entity[:url]
link_to_url(entity)
elsif entity[:hashtag]
link_to_hashtag(entity)
elsif entity[:screen_name]
link_to_mention(entity)
end
end
html.html_safe # rubocop:disable Rails/OutputSafety
end
# Differs from `TextFormatter` by skipping HTML tags and entities
def entities
@entities ||= begin
gaps = []
total_offset = 0
escaped = text.gsub(/<[^>]*>|&#[0-9]+;/) do |match|
total_offset += match.length - 1
end_offset = Regexp.last_match.end(0)
gaps << [end_offset - total_offset, total_offset]
' '
end
Extractor.extract_entities_with_indices(escaped, extract_url_without_protocol: false).map do |entity|
start_pos, end_pos = entity[:indices]
offset_idx = gaps.rindex { |gap| gap.first <= start_pos }
offset = offset_idx.nil? ? 0 : gaps[offset_idx].last
entity.merge(indices: [start_pos + offset, end_pos + offset])
end
end
end
private
# Differs from `TextFormatter` in that it keeps HTML; but it sanitizes at the end to remain safe
def rewrite
entities.sort_by! do |entity|
entity[:indices].first
end
result = ''.dup
last_index = entities.reduce(0) do |index, entity|
indices = entity[:indices]
result << text[index...indices.first]
result << yield(entity)
indices.last
end
result << text[last_index..-1]
Sanitize.fragment(result, Sanitize::Config::MASTODON_OUTGOING)
end
def format_markdown(html)
html = markdown_formatter.render(html)
html.delete("\r").delete("\n")
end
def markdown_formatter
extensions = {
autolink: true,
no_intra_emphasis: true,
fenced_code_blocks: true,
disable_indented_code_blocks: true,
strikethrough: true,
lax_spacing: true,
space_after_headers: true,
superscript: true,
underline: true,
highlight: true,
footnotes: false,
}
renderer = HTMLRenderer.new({
filter_html: false,
escape_html: false,
no_images: true,
no_styles: true,
safe_links_only: true,
hard_wrap: true,
link_attributes: { target: '_blank', rel: 'nofollow noopener' },
}) do |url|
link_to_url({ url: url })
end
Redcarpet::Markdown.new(renderer, extensions)
end
end