- # frozen_string_literal: true
-
- class FetchAtomService < BaseService
- include JsonLdHelper
-
- def call(url)
- return if url.blank?
-
- result = process(url)
-
- # retry without ActivityPub
- result ||= process(url) if @unsupported_activity
-
- result
- rescue OpenSSL::SSL::SSLError => e
- Rails.logger.debug "SSL error: #{e}"
- nil
- rescue HTTP::ConnectionError => e
- Rails.logger.debug "HTTP ConnectionError: #{e}"
- nil
- end
-
- private
-
- def process(url, terminal = false)
- @url = url
- perform_request
- process_response(terminal)
- end
-
- def perform_request
- accept = 'text/html'
- accept = 'application/activity+json, application/ld+json, application/atom+xml, ' + accept unless @unsupported_activity
-
- @response = Request.new(:get, @url)
- .add_headers('Accept' => accept)
- .perform
- end
-
- def process_response(terminal = false)
- return nil if @response.code != 200
-
- if @response.mime_type == 'application/atom+xml'
- [@url, { prefetched_body: @response.to_s }, :ostatus]
- elsif ['application/activity+json', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'].include?(@response.mime_type)
- json = body_to_json(@response.to_s)
- if supported_context?(json) && json['type'] == 'Person' && json['inbox'].present?
- [json['id'], { prefetched_body: @response.to_s, id: true }, :activitypub]
- else
- @unsupported_activity = true
- nil
- end
- elsif @response['Link'] && !terminal
- process_headers
- elsif @response.mime_type == 'text/html' && !terminal
- process_html
- end
- end
-
- def process_html
- page = Nokogiri::HTML(@response.to_s)
-
- json_link = page.xpath('//link[@rel="alternate"]').find { |link| ['application/activity+json', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'].include?(link['type']) }
- atom_link = page.xpath('//link[@rel="alternate"]').find { |link| link['type'] == 'application/atom+xml' }
-
- result ||= process(json_link['href'], terminal: true) unless json_link.nil? || @unsupported_activity
- result ||= process(atom_link['href'], terminal: true) unless atom_link.nil?
-
- result
- end
-
- def process_headers
- link_header = LinkHeader.parse(@response['Link'].is_a?(Array) ? @response['Link'].first : @response['Link'])
-
- json_link = link_header.find_link(%w(rel alternate), %w(type application/activity+json)) || link_header.find_link(%w(rel alternate), ['type', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'])
- atom_link = link_header.find_link(%w(rel alternate), %w(type application/atom+xml))
-
- result ||= process(json_link.href, terminal: true) unless json_link.nil? || @unsupported_activity
- result ||= process(atom_link.href, terminal: true) unless atom_link.nil?
-
- result
- end
- end
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