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mastodon/app/services/fetch_atom_service.rb
Akihiko Odaki 40e5d2303b Validate HTTP response length while receiving (#6891)
to_s method of HTTP::Response keeps blocking while it receives the whole
content, no matter how it is big. This means it may waste time to receive
unacceptably large files. It may also consume memory and disk in the
process. This solves the inefficency by checking response length while
receiving.
2018-03-26 14:02:10 +02:00

90 lines
3.1 KiB
Ruby

# 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 { |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