From 39cdf61ab7be267a374c472c230b315971ead43c Mon Sep 17 00:00:00 2001 From: Eugen Rochko Date: Fri, 5 Nov 2021 23:23:05 +0100 Subject: Add support for structured data and more OpenGraph tags to link cards (#16938) Save preview cards under their canonical URL Increase max redirects to follow from 2 to 3 --- app/services/fetch_link_card_service.rb | 79 ++++++++++++--------------------- 1 file changed, 29 insertions(+), 50 deletions(-) (limited to 'app/services') diff --git a/app/services/fetch_link_card_service.rb b/app/services/fetch_link_card_service.rb index 5732ce8ac..51956ce7e 100644 --- a/app/services/fetch_link_card_service.rb +++ b/app/services/fetch_link_card_service.rb @@ -13,12 +13,12 @@ class FetchLinkCardService < BaseService }iox def call(status) - @status = status - @url = parse_urls + @status = status + @original_url = parse_urls - return if @url.nil? || @status.preview_cards.any? + return if @original_url.nil? || @status.preview_cards.any? - @url = @url.to_s + @url = @original_url.to_s RedisLock.acquire(lock_options) do |lock| if lock.acquired? @@ -31,7 +31,7 @@ class FetchLinkCardService < BaseService attach_card if @card&.persisted? rescue HTTP::Error, OpenSSL::SSL::SSLError, Addressable::URI::InvalidURIError, Mastodon::HostValidationError, Mastodon::LengthValidationError => e - Rails.logger.debug "Error fetching link #{@url}: #{e}" + Rails.logger.debug "Error fetching link #{@original_url}: #{e}" nil end @@ -47,6 +47,12 @@ class FetchLinkCardService < BaseService return @html if defined?(@html) Request.new(:get, @url).add_headers('Accept' => 'text/html', 'User-Agent' => Mastodon::Version.user_agent + ' Bot').perform do |res| + # We follow redirects, and ideally we want to save the preview card for + # the destination URL and not any link shortener in-between, so here + # we set the URL to the one of the last response in the redirect chain + @url = res.request.uri.to_s.to_s + @card = PreviewCard.find_or_initialize_by(url: @url) if @card.url != @url + if res.code == 200 && res.mime_type == 'text/html' @html_charset = res.charset @html = res.body_with_limit @@ -63,12 +69,15 @@ class FetchLinkCardService < BaseService end def parse_urls - if @status.local? - urls = @status.text.scan(URL_PATTERN).map { |array| Addressable::URI.parse(array[1]).normalize } - else - html = Nokogiri::HTML(@status.text) - links = html.css('a') - urls = links.filter_map { |a| Addressable::URI.parse(a['href']) unless skip_link?(a) }.filter_map(&:normalize) + urls = begin + if @status.local? + @status.text.scan(URL_PATTERN).map { |array| Addressable::URI.parse(array[1]).normalize } + else + document = Nokogiri::HTML(@status.text) + links = document.css('a') + + links.filter_map { |a| Addressable::URI.parse(a['href']) unless skip_link?(a) }.filter_map(&:normalize) + end end urls.reject { |uri| bad_url?(uri) }.first @@ -79,18 +88,16 @@ class FetchLinkCardService < BaseService uri.host.blank? || TagManager.instance.local_url?(uri.to_s) || !%w(http https).include?(uri.scheme) end - # rubocop:disable Naming/MethodParameterName - def mention_link?(a) + def mention_link?(anchor) @status.mentions.any? do |mention| - a['href'] == ActivityPub::TagManager.instance.url_for(mention.account) + anchor['href'] == ActivityPub::TagManager.instance.url_for(mention.account) end end - def skip_link?(a) + def skip_link?(anchor) # Avoid links for hashtags and mentions (microformats) - a['rel']&.include?('tag') || a['class']&.match?(/u-url|h-card/) || mention_link?(a) + anchor['rel']&.include?('tag') || anchor['class']&.match?(/u-url|h-card/) || mention_link?(anchor) end - # rubocop:enable Naming/MethodParameterName def attempt_oembed service = FetchOEmbedService.new @@ -139,42 +146,14 @@ class FetchLinkCardService < BaseService def attempt_opengraph return if html.nil? - detector = CharlockHolmes::EncodingDetector.new - detector.strip_tags = true - - guess = detector.detect(@html, @html_charset) - encoding = guess&.fetch(:confidence, 0).to_i > 60 ? guess&.fetch(:encoding, nil) : nil - page = Nokogiri::HTML(@html, nil, encoding) - player_url = meta_property(page, 'twitter:player') - - if player_url && !bad_url?(Addressable::URI.parse(player_url)) - @card.type = :video - @card.width = meta_property(page, 'twitter:player:width') || 0 - @card.height = meta_property(page, 'twitter:player:height') || 0 - @card.html = content_tag(:iframe, nil, src: player_url, - width: @card.width, - height: @card.height, - allowtransparency: 'true', - scrolling: 'no', - frameborder: '0') - else - @card.type = :link - end - - @card.title = meta_property(page, 'og:title').presence || page.at_xpath('//title')&.content || '' - @card.description = meta_property(page, 'og:description').presence || meta_property(page, 'description') || '' - @card.image_remote_url = (Addressable::URI.parse(@url) + meta_property(page, 'og:image')).to_s if meta_property(page, 'og:image') - - return if @card.title.blank? && @card.html.blank? - - @card.save_with_optional_image! - end + link_details_extractor = LinkDetailsExtractor.new(@url, @html, @html_charset) - def meta_property(page, property) - page.at_xpath("//meta[contains(concat(' ', normalize-space(@property), ' '), ' #{property} ')]")&.attribute('content')&.value || page.at_xpath("//meta[@name=\"#{property}\"]")&.attribute('content')&.value + @card = PreviewCard.find_or_initialize_by(url: link_details_extractor.canonical_url) if link_details_extractor.canonical_url != @card.url + @card.assign_attributes(link_details_extractor.to_preview_card_attributes) + @card.save_with_optional_image! unless @card.title.blank? && @card.html.blank? end def lock_options - { redis: Redis.current, key: "fetch:#{@url}", autorelease: 15.minutes.seconds } + { redis: Redis.current, key: "fetch:#{@original_url}", autorelease: 15.minutes.seconds } end end -- cgit