mastodon/app/services/fetch_atom_service.rb

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# 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}"
2017-06-29 13:04:07 +02:00
nil
rescue HTTP::ConnectionError => e
Rails.logger.debug "HTTP ConnectionError: #{e}"
nil
end
private
def process(url, terminal = false)
@url = url
perform_request { |response| process_response(response, terminal) }
end
def perform_request(&block)
accept = 'text/html'
accept = 'application/activity+json, application/ld+json, application/atom+xml, ' + accept unless @unsupported_activity
Request.new(:get, @url).add_headers('Accept' => accept).perform(&block)
end
def process_response(response, terminal = false)
return nil if response.code != 200
if response.mime_type == 'application/atom+xml'
[@url, { prefetched_body: response.body_with_limit }, :ostatus]
elsif ['application/activity+json', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'].include?(response.mime_type)
body = response.body_with_limit
json = body_to_json(body)
if supported_context?(json) && json['type'] == 'Person' && json['inbox'].present?
[json['id'], { prefetched_body: body, id: true }, :activitypub]
elsif supported_context?(json) && json['type'] == 'Note'
[json['id'], { prefetched_body: body, id: true }, :activitypub]
else
@unsupported_activity = true
nil
end
elsif !terminal
link_header = response['Link'] && parse_link_header(response)
if link_header&.find_link(%w(rel alternate))
process_link_headers(link_header)
elsif response.mime_type == 'text/html'
process_html(response)
end
end
end
def process_html(response)
page = Nokogiri::HTML(response.body_with_limit)
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_link_headers(link_header)
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
def parse_link_header(response)
LinkHeader.parse(response['Link'].is_a?(Array) ? response['Link'].first : response['Link'])
end
end