# frozen_string_literal: true class FetchLinkCardService < BaseService include HttpHelper URL_PATTERN = %r{https?://\S+} def call(status) # Get first http/https URL that isn't local url = parse_urls(status) return if url.nil? url = url.to_s card = PreviewCard.where(status: status).first_or_initialize(status: status, url: url) res = http_client.head(url) return if res.code != 200 || res.mime_type != 'text/html' attempt_opengraph(card, url) unless attempt_oembed(card, url) rescue HTTP::ConnectionError, OpenSSL::SSL::SSLError nil end private def parse_urls(status) if status.local? urls = status.text.match(URL_PATTERN).to_a.map { |uri| Addressable::URI.parse(uri).normalize } else html = Nokogiri::HTML(status.text) links = html.css('a') urls = links.map { |a| Addressable::URI.parse(a['href']).normalize unless skip_link?(a) }.compact end urls.reject { |uri| bad_url?(uri) }.first end def bad_url?(uri) # Avoid local instance URLs and invalid URLs uri.host.blank? || TagManager.instance.local_url?(uri.to_s) || !%w(http https).include?(uri.scheme) end def skip_link?(a) # Avoid links for hashtags and mentions (microformats) a['rel']&.include?('tag') || a['class']&.include?('u-url') end def attempt_oembed(card, url) response = OEmbed::Providers.get(url) card.type = response.type card.title = response.respond_to?(:title) ? response.title : '' card.author_name = response.respond_to?(:author_name) ? response.author_name : '' card.author_url = response.respond_to?(:author_url) ? response.author_url : '' card.provider_name = response.respond_to?(:provider_name) ? response.provider_name : '' card.provider_url = response.respond_to?(:provider_url) ? response.provider_url : '' card.width = 0 card.height = 0 case card.type when 'link' card.image = URI.parse(response.thumbnail_url) if response.respond_to?(:thumbnail_url) when 'photo' card.url = response.url card.width = response.width.presence || 0 card.height = response.height.presence || 0 when 'video' card.width = response.width.presence || 0 card.height = response.height.presence || 0 card.html = Formatter.instance.sanitize(response.html, Sanitize::Config::MASTODON_OEMBED) when 'rich' # Most providers rely on <script> tags, which is a no-no return false end card.save_with_optional_image! rescue OEmbed::NotFound false end def attempt_opengraph(card, url) response = http_client.get(url) return if response.code != 200 || response.mime_type != 'text/html' html = response.to_s detector = CharlockHolmes::EncodingDetector.new detector.strip_tags = true guess = detector.detect(html, response.charset) page = Nokogiri::HTML(html, nil, guess&.fetch(:encoding)) card.type = :link card.title = meta_property(page, 'og:title') || page.at_xpath('//title')&.content card.description = meta_property(page, 'og:description') || meta_property(page, 'description') card.image_remote_url = meta_property(page, 'og:image') if meta_property(page, 'og:image') return if card.title.blank? card.save_with_optional_image! end def meta_property(html, property) html.at_xpath("//meta[@property=\"#{property}\"]")&.attribute('content')&.value || html.at_xpath("//meta[@name=\"#{property}\"]")&.attribute('content')&.value end end