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91 lines
3.1 KiB
91 lines
3.1 KiB
# frozen_string_literal: true |
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class FetchResourceService < BaseService |
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include JsonLdHelper |
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ACCEPT_HEADER = 'application/activity+json, application/ld+json; profile="https://www.w3.org/ns/activitystreams", text/html;q=0.1' |
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ACTIVITY_STREAM_LINK_TYPES = ['application/activity+json', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'].freeze |
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attr_reader :response_code |
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def call(url) |
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return if url.blank? |
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process(url) |
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rescue HTTP::Error, OpenSSL::SSL::SSLError, Addressable::URI::InvalidURIError, Mastodon::HostValidationError, Mastodon::LengthValidationError => e |
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Rails.logger.debug { "Error fetching resource #{@url}: #{e}" } |
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nil |
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end |
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private |
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def process(url, terminal: false) |
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@url = url |
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perform_request { |response| process_response(response, terminal) } |
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end |
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def perform_request(&block) |
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Request.new(:get, @url).tap do |request| |
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request.add_headers('Accept' => ACCEPT_HEADER) |
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# In a real setting we want to sign all outgoing requests, |
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# in case the remote server has secure mode enabled and requires |
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# authentication on all resources. However, during development, |
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# sending request signatures with an inaccessible host is useless |
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# and prevents even public resources from being fetched, so |
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# don't do it |
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request.on_behalf_of(Account.representative) unless Rails.env.development? |
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end.perform(&block) |
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end |
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def process_response(response, terminal = false) |
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@response_code = response.code |
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return nil if response.code != 200 |
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if valid_activitypub_content_type?(response) |
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body = response.body_with_limit |
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json = body_to_json(body) |
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return unless supported_context?(json) && (equals_or_includes_any?(json['type'], ActivityPub::FetchRemoteActorService::SUPPORTED_TYPES) || expected_type?(json)) |
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if json['id'] != @url |
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return if terminal |
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return process(json['id'], terminal: true) |
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end |
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[@url, { prefetched_body: body }] |
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elsif !terminal |
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link_header = response['Link'] && parse_link_header(response) |
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if link_header&.find_link(%w(rel alternate)) |
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process_link_headers(link_header) |
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elsif response.mime_type == 'text/html' |
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process_html(response) |
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end |
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end |
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end |
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def expected_type?(json) |
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equals_or_includes_any?(json['type'], ActivityPub::Activity::Create::SUPPORTED_TYPES + ActivityPub::Activity::Create::CONVERTED_TYPES) |
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end |
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def process_html(response) |
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page = Nokogiri::HTML(response.body_with_limit) |
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json_link = page.xpath('//link[@rel="alternate"]').find { |link| ACTIVITY_STREAM_LINK_TYPES.include?(link['type']) } |
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process(json_link['href'], terminal: true) unless json_link.nil? |
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end |
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def process_link_headers(link_header) |
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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"']) |
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process(json_link.href, terminal: true) unless json_link.nil? |
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end |
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def parse_link_header(response) |
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LinkHeader.parse(response['Link'].is_a?(Array) ? response['Link'].first : response['Link']) |
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end |
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end
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