Fix #2706 - Always respond with 200 to PuSH payloads (#2733)

Fix #2196 - Respond with 201 when Salmon accepted, 400 when unverified
Fix #2629 - Correctly handle confirm_domain? for local accounts
Unify rules for extracting author acct from XML, prefer <email>, fall back
to <name> + <uri> (see also #2017, #2172)

app/services/fetch_remote_status_service.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class FetchRemoteStatusService < BaseService
+  include AuthorExtractor
+
   def call(url, prefetched_body = nil)
     if prefetched_body.nil?
       atom_url, body = FetchAtomService.new.call(url)
@@ -21,37 +23,19 @@ class FetchRemoteStatusService < BaseService
     xml = Nokogiri::XML(body)
     xml.encoding = 'utf-8'
 
-    account = extract_author(url, xml)
+    account = author_from_xml(xml.at_xpath('/xmlns:entry', xmlns: TagManager::XMLNS))
+    domain  = Addressable::URI.parse(url).normalize.host
 
-    return nil if account.nil?
+    return nil unless !account.nil? && confirmed_domain?(domain, account)
 
     statuses = ProcessFeedService.new.call(body, account)
-
     statuses.first
-  end
-
-  def extract_author(url, xml)
-    url_parts = Addressable::URI.parse(url).normalize
-    username  = xml.at_xpath('//xmlns:author/xmlns:name').try(:content)
-    domain    = url_parts.host
-
-    return nil if username.nil?
-
-    Rails.logger.debug "Going to webfinger #{username}@#{domain}"
-
-    account = FollowRemoteAccountService.new.call("#{username}@#{domain}")
-
-    # If the author's confirmed URLs do not match the domain of the URL
-    # we are reading this from, abort
-    return nil unless confirmed_domain?(domain, account)
-
-    account
   rescue Nokogiri::XML::XPath::SyntaxError
     Rails.logger.debug 'Invalid XML or missing namespace'
     nil
   end
 
   def confirmed_domain?(domain, account)
-    domain.casecmp(account.domain).zero? || domain.casecmp(Addressable::URI.parse(account.remote_url).normalize.host).zero?
+    account.domain.nil? || domain.casecmp(account.domain).zero? || domain.casecmp(Addressable::URI.parse(account.remote_url).normalize.host).zero?
   end
 end