mastodon/app/services/process_feed_service.rb
Eugen Rochko 4bec613897 Fix #24 - Thread resolving for remote statuses
This is a big one, so let me enumerate:

Accounts as well as stream entry pages now contain Link headers that
reference the Atom feed and Webfinger URL for the former and Atom entry
for the latter. So you only need to HEAD those resources to get that
information, no need to download and parse HTML <link>s.

ProcessFeedService will now queue ThreadResolveWorker for each remote
status that it cannot find otherwise. Furthermore, entries are now
processed in reverse order (from bottom to top) in case a newer entry
references a chronologically previous one.

ThreadResolveWorker uses FetchRemoteStatusService to obtain a status
and attach the child status it was queued for to it.

FetchRemoteStatusService looks up the URL, first with a HEAD, tests
if it's an Atom feed, in which case it processes it directly. Next
for Link headers to the Atom feed, in which case that is fetched
and processed. Lastly if it's HTML, it is checked for <link>s to the Atom
feed, and if such is found, that is fetched and processed. The account for
the status is derived from author/name attribute in the XML and the hostname
in the URL (domain). FollowRemoteAccountService and ProcessFeedService
are used.

This means that potentially threads are resolved recursively until a dead-end
is encountered, however it is performed asynchronously over background jobs,
so it should be ok.
2016-09-21 01:50:31 +02:00

224 lines
6.5 KiB
Ruby

class ProcessFeedService < BaseService
# Create local statuses from an Atom feed
# @param [String] body Atom feed
# @param [Account] account Account this feed belongs to
# @return [Enumerable] created statuses
def call(body, account)
xml = Nokogiri::XML(body)
update_remote_profile_service.(xml.at_xpath('/xmlns:feed/xmlns:author'), account) unless xml.at_xpath('/xmlns:feed').nil?
xml.xpath('//xmlns:entry').reverse_each.map { |entry| process_entry(account, entry) }.compact
end
private
def process_entry(account, entry)
return unless [:note, :comment, :activity].include? object_type(entry)
status = Status.find_by(uri: activity_id(entry))
# If we already have a post and the verb is now "delete", we gotta delete it and move on!
if !status.nil? && verb(entry) == :delete
delete_post!(status)
return
end
return unless status.nil?
status = Status.new(uri: activity_id(entry), url: activity_link(entry), account: account, text: content(entry), created_at: published(entry), updated_at: updated(entry))
if verb(entry) == :share
add_reblog!(entry, status)
elsif verb(entry) == :post
if thread_id(entry).nil?
add_post!(entry, status)
else
add_reply!(entry, status)
end
end
# If we added a status, go through accounts it mentions and create respective relations
# Also record all media attachments for the status and for the reblogged status if present
unless status.new_record?
record_remote_mentions(status, entry.xpath('./xmlns:link[@rel="mentioned"]'))
process_attachments(entry, status)
process_attachments(entry.xpath('./activity:object'), status.reblog) if status.reblog?
DistributionWorker.perform_async(status.id)
end
return status
end
def record_remote_mentions(status, links)
# Here we have to do a reverse lookup of local accounts by their URL!
# It's not pretty at all! I really wish all these protocols sticked to
# using acct:username@domain only! It would make things so much easier
# and tidier
links.each do |mention_link|
href = Addressable::URI.parse(mention_link.attribute('href').value)
if href.host == Rails.configuration.x.local_domain
# A local user is mentioned
mentioned_account = Account.find_local(href.path.gsub('/users/', ''))
unless mentioned_account.nil?
mentioned_account.mentions.where(status: status).first_or_create(status: status)
NotificationMailer.mention(mentioned_account, status).deliver_later
end
else
# What to do about remote user?
# Are we supposed to do a search in the database by URL?
# We could technically open the URL, look for LRDD tags, get webfinger that way,
# finally acquire the acct:username@domain form, and then check DB
end
end
end
def process_attachments(entry, status)
entry.xpath('./xmlns:link[@rel="enclosure"]').each do |enclosure_link|
next if enclosure_link.attribute('href').nil?
media = MediaAttachment.new(account: status.account, status: status, remote_url: enclosure_link.attribute('href').value)
media.file_remote_url = enclosure_link.attribute('href').value
media.save
end
end
def add_post!(_entry, status)
status.save!
end
def add_reblog!(entry, status)
status.reblog = find_original_status(entry, target_id(entry))
if status.reblog.nil?
status.reblog = fetch_remote_status(entry)
end
if !status.reblog.nil?
status.save!
NotificationMailer.reblog(status.reblog, status.account).deliver_later if status.reblog.local?
end
end
def add_reply!(entry, status)
status.thread = find_original_status(entry, thread_id(entry))
status.save!
if status.thread.nil? && !thread_href(entry).nil?
ThreadResolveWorker.perform_async(status.id, thread_href(entry))
end
end
def delete_post!(status)
remove_status_service.(status)
end
def find_original_status(_xml, id)
return nil if id.nil?
if TagManager.instance.local_id?(id)
Status.find(TagManager.instance.unique_tag_to_local_id(id, 'Status'))
else
Status.find_by(uri: id)
end
end
def fetch_remote_status(xml)
username = xml.at_xpath('./activity:object/xmlns:author/xmlns:name').content
url = xml.at_xpath('./activity:object/xmlns:author/xmlns:uri').content
domain = Addressable::URI.parse(url).host
account = Account.find_by(username: username, domain: domain)
if account.nil?
account = follow_remote_account_service.("#{username}@#{domain}")
end
status = Status.new(account: account, uri: target_id(xml), text: target_content(xml), url: target_url(xml), created_at: published(xml), updated_at: updated(xml))
status.thread = find_original_status(xml, thread_id(xml))
status.save
if status.saved? && status.thread.nil? && !thread_href(xml).nil?
ThreadResolveWorker.perform_async(status.id, thread_href(xml))
end
status
rescue Goldfinger::Error, HTTP::Error
nil
end
def published(xml)
xml.at_xpath('./xmlns:published').content
end
def updated(xml)
xml.at_xpath('./xmlns:updated').content
end
def content(xml)
xml.at_xpath('./xmlns:content').content
end
def thread_id(xml)
xml.at_xpath('./thr:in-reply-to').attribute('ref').value
rescue
nil
end
def thread_href(xml)
xml.at_xpath('./thr:in-reply-to').attribute('href').value
rescue
nil
end
def target_id(xml)
xml.at_xpath('.//activity:object/xmlns:id').content
rescue
nil
end
def activity_id(xml)
xml.at_xpath('./xmlns:id').content
end
def activity_link(xml)
xml.at_xpath('./xmlns:link[@rel="alternate"]').attribute('href').value
rescue
''
end
def target_content(xml)
xml.at_xpath('.//activity:object/xmlns:content').content
end
def target_url(xml)
xml.at_xpath('.//activity:object/xmlns:link[@rel="alternate"]').attribute('href').value
end
def object_type(xml)
xml.at_xpath('./activity:object-type').content.gsub('http://activitystrea.ms/schema/1.0/', '').to_sym
rescue
:note
end
def verb(xml)
xml.at_xpath('./activity:verb').content.gsub('http://activitystrea.ms/schema/1.0/', '').to_sym
rescue
:post
end
def follow_remote_account_service
@follow_remote_account_service ||= FollowRemoteAccountService.new
end
def update_remote_profile_service
@update_remote_profile_service ||= UpdateRemoteProfileService.new
end
def remove_status_service
@remove_status_service ||= RemoveStatusService.new
end
end