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