Introduce Ostatus name space (#4164)

* Wrap methods of ProcessFeedService::ProcessEntry in classes

This is a change same with 425acecfdb15093a265b191120fb2d4e4c4135c4, except
that it has the following changes:

* Revert irrelevant change in find_or_create_conversation
* Fix error handling for RemoteActivity

* Introduce Ostatus name space

23 files changed, 516 insertions, 447 deletions

diff --git a/app/controllers/accounts_controller.rb b/app/controllers/accounts_controller.rb
index a95aabf1d81..37a1e540f40 100644
--- a/app/controllers/accounts_controller.rb
+++ b/app/controllers/accounts_controller.rb
@@ -13,7 +13,7 @@ class AccountsController < ApplicationController
 
       format.atom do
         @entries = @account.stream_entries.where(hidden: false).with_includes.paginate_by_max_id(20, params[:max_id], params[:since_id])
-        render xml: AtomSerializer.render(AtomSerializer.new.feed(@account, @entries.to_a))
+        render xml: Ostatus::AtomSerializer.render(Ostatus::AtomSerializer.new.feed(@account, @entries.to_a))
       end
 
       format.json do
diff --git a/app/controllers/stream_entries_controller.rb b/app/controllers/stream_entries_controller.rb
index 54a43523845..e3db77caaa2 100644
--- a/app/controllers/stream_entries_controller.rb
+++ b/app/controllers/stream_entries_controller.rb
@@ -19,7 +19,7 @@ class StreamEntriesController < ApplicationController
       end
 
       format.atom do
-        render xml: AtomSerializer.render(AtomSerializer.new.entry(@stream_entry, true))
+        render xml: Ostatus::AtomSerializer.render(Ostatus::AtomSerializer.new.entry(@stream_entry, true))
       end
     end
   end
diff --git a/app/lib/ostatus/activity/base.rb b/app/lib/ostatus/activity/base.rb
new file mode 100644
index 00000000000..f528815b3e1
--- /dev/null
+++ b/app/lib/ostatus/activity/base.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+class Ostatus::Activity::Base
+  def initialize(xml, account = nil)
+    @xml = xml
+    @account = account
+  end
+
+  def status?
+    [:activity, :note, :comment].include?(type)
+  end
+
+  def verb
+    raw = @xml.at_xpath('./activity:verb', activity: TagManager::AS_XMLNS).content
+    TagManager::VERBS.key(raw)
+  rescue
+    :post
+  end
+
+  def type
+    raw = @xml.at_xpath('./activity:object-type', activity: TagManager::AS_XMLNS).content
+    TagManager::TYPES.key(raw)
+  rescue
+    :activity
+  end
+
+  def id
+    @xml.at_xpath('./xmlns:id', xmlns: TagManager::XMLNS).content
+  end
+
+  def url
+    link = @xml.at_xpath('./xmlns:link[@rel="alternate"]', xmlns: TagManager::XMLNS)
+    link.nil? ? nil : link['href']
+  end
+
+  private
+
+  def find_status(uri)
+    if TagManager.instance.local_id?(uri)
+      local_id = TagManager.instance.unique_tag_to_local_id(uri, 'Status')
+      return Status.find_by(id: local_id)
+    end
+
+    Status.find_by(uri: uri)
+  end
+
+  def redis
+    Redis.current
+  end
+end
diff --git a/app/lib/ostatus/activity/creation.rb b/app/lib/ostatus/activity/creation.rb
new file mode 100644
index 00000000000..c54d64fd776
--- /dev/null
+++ b/app/lib/ostatus/activity/creation.rb
@@ -0,0 +1,149 @@
+# frozen_string_literal: true
+
+class Ostatus::Activity::Creation < Ostatus::Activity::Base
+  def perform
+    if redis.exists("delete_upon_arrival:#{@account.id}:#{id}")
+      Rails.logger.debug "Delete for status #{id} was queued, ignoring"
+      return [nil, false]
+    end
+
+    return [nil, false] if @account.suspended?
+
+    Rails.logger.debug "Creating remote status #{id}"
+
+    # Return early if status already exists in db
+    status = find_status(id)
+
+    return [status, false] unless status.nil?
+
+    status = Status.create!(
+      uri: id,
+      url: url,
+      account: @account,
+      reblog: reblog,
+      text: content,
+      spoiler_text: content_warning,
+      created_at: published,
+      reply: thread?,
+      language: content_language,
+      visibility: visibility_scope,
+      conversation: find_or_create_conversation,
+      thread: thread? ? find_status(thread.first) : nil
+    )
+
+    save_mentions(status)
+    save_hashtags(status)
+    save_media(status)
+
+    if thread? && status.thread.nil?
+      Rails.logger.debug "Trying to attach #{status.id} (#{id}) to #{thread.first}"
+      ThreadResolveWorker.perform_async(status.id, thread.second)
+    end
+
+    Rails.logger.debug "Queuing remote status #{status.id} (#{id}) for distribution"
+
+    LinkCrawlWorker.perform_async(status.id) unless status.spoiler_text?
+    DistributionWorker.perform_async(status.id)
+
+    [status, true]
+  end
+
+  def content
+    @xml.at_xpath('./xmlns:content', xmlns: TagManager::XMLNS).content
+  end
+
+  def content_language
+    @xml.at_xpath('./xmlns:content', xmlns: TagManager::XMLNS)['xml:lang']&.presence || 'en'
+  end
+
+  def content_warning
+    @xml.at_xpath('./xmlns:summary', xmlns: TagManager::XMLNS)&.content || ''
+  end
+
+  def visibility_scope
+    @xml.at_xpath('./mastodon:scope', mastodon: TagManager::MTDN_XMLNS)&.content&.to_sym || :public
+  end
+
+  def published
+    @xml.at_xpath('./xmlns:published', xmlns: TagManager::XMLNS).content
+  end
+
+  def thread?
+    !@xml.at_xpath('./thr:in-reply-to', thr: TagManager::THR_XMLNS).nil?
+  end
+
+  def thread
+    thr = @xml.at_xpath('./thr:in-reply-to', thr: TagManager::THR_XMLNS)
+    [thr['ref'], thr['href']]
+  end
+
+  private
+
+  def find_or_create_conversation
+    uri = @xml.at_xpath('./ostatus:conversation', ostatus: TagManager::OS_XMLNS)&.attribute('ref')&.content
+    return if uri.nil?
+
+    if TagManager.instance.local_id?(uri)
+      local_id = TagManager.instance.unique_tag_to_local_id(uri, 'Conversation')
+      return Conversation.find_by(id: local_id)
+    end
+
+    Conversation.find_by(uri: uri) || Conversation.create!(uri: uri)
+  end
+
+  def save_mentions(parent)
+    processed_account_ids = []
+
+    @xml.xpath('./xmlns:link[@rel="mentioned"]', xmlns: TagManager::XMLNS).each do |link|
+      next if [TagManager::TYPES[:group], TagManager::TYPES[:collection]].include? link['ostatus:object-type']
+
+      mentioned_account = account_from_href(link['href'])
+
+      next if mentioned_account.nil? || processed_account_ids.include?(mentioned_account.id)
+
+      mentioned_account.mentions.where(status: parent).first_or_create(status: parent)
+
+      # So we can skip duplicate mentions
+      processed_account_ids << mentioned_account.id
+    end
+  end
+
+  def save_hashtags(parent)
+    tags = @xml.xpath('./xmlns:category', xmlns: TagManager::XMLNS).map { |category| category['term'] }.select(&:present?)
+    ProcessHashtagsService.new.call(parent, tags)
+  end
+
+  def save_media(parent)
+    do_not_download = DomainBlock.find_by(domain: parent.account.domain)&.reject_media?
+
+    @xml.xpath('./xmlns:link[@rel="enclosure"]', xmlns: TagManager::XMLNS).each do |link|
+      next unless link['href']
+
+      media = MediaAttachment.where(status: parent, remote_url: link['href']).first_or_initialize(account: parent.account, status: parent, remote_url: link['href'])
+      parsed_url = Addressable::URI.parse(link['href']).normalize
+
+      next if !%w(http https).include?(parsed_url.scheme) || parsed_url.host.empty?
+
+      media.save
+
+      next if do_not_download
+
+      begin
+        media.file_remote_url = link['href']
+        media.save!
+      rescue ActiveRecord::RecordInvalid
+        next
+      end
+    end
+  end
+
+  def account_from_href(href)
+    url = Addressable::URI.parse(href).normalize
+
+    if TagManager.instance.web_domain?(url.host)
+      Account.find_local(url.path.gsub('/users/', ''))
+    else
+      Account.where(uri: href).or(Account.where(url: href)).first || FetchRemoteAccountService.new.call(href)
+    end
+  end
+end
diff --git a/app/lib/ostatus/activity/deletion.rb b/app/lib/ostatus/activity/deletion.rb
new file mode 100644
index 00000000000..c4d05a4679f
--- /dev/null
+++ b/app/lib/ostatus/activity/deletion.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class Ostatus::Activity::Deletion < Ostatus::Activity::Base
+  def perform
+    Rails.logger.debug "Deleting remote status #{id}"
+    status = Status.find_by(uri: id, account: @account)
+
+    if status.nil?
+      redis.setex("delete_upon_arrival:#{@account.id}:#{id}", 6 * 3_600, id)
+    else
+      RemoveStatusService.new.call(status)
+    end
+  end
+end
diff --git a/app/lib/ostatus/activity/general.rb b/app/lib/ostatus/activity/general.rb
new file mode 100644
index 00000000000..3ff7a039a68
--- /dev/null
+++ b/app/lib/ostatus/activity/general.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class Ostatus::Activity::General < Ostatus::Activity::Base
+  def specialize
+    special_class&.new(@xml, @account)
+  end
+
+  private
+
+  def special_class
+    case verb
+    when :post
+      Ostatus::Activity::Post
+    when :share
+      Ostatus::Activity::Share
+    when :delete
+      Ostatus::Activity::Deletion
+    end
+  end
+end
diff --git a/app/lib/ostatus/activity/post.rb b/app/lib/ostatus/activity/post.rb
new file mode 100644
index 00000000000..8028db2f8d5
--- /dev/null
+++ b/app/lib/ostatus/activity/post.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class Ostatus::Activity::Post < Ostatus::Activity::Creation
+  def perform
+    status, just_created = super
+
+    if just_created
+      status.mentions.includes(:account).each do |mention|
+        mentioned_account = mention.account
+        next unless mentioned_account.local?
+        NotifyService.new.call(mentioned_account, mention)
+      end
+    end
+
+    status
+  end
+
+  private
+
+  def reblog
+    nil
+  end
+end
diff --git a/app/lib/ostatus/activity/remote.rb b/app/lib/ostatus/activity/remote.rb
new file mode 100644
index 00000000000..755f885e625
--- /dev/null
+++ b/app/lib/ostatus/activity/remote.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Ostatus::Activity::Remote < Ostatus::Activity::Base
+  def perform
+    find_status(id) || FetchRemoteStatusService.new.call(url)
+  end
+end
diff --git a/app/lib/ostatus/activity/share.rb b/app/lib/ostatus/activity/share.rb
new file mode 100644
index 00000000000..73aac58ed27
--- /dev/null
+++ b/app/lib/ostatus/activity/share.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+class Ostatus::Activity::Share < Ostatus::Activity::Creation
+  def perform
+    return if reblog.nil?
+
+    status, just_created = super
+    NotifyService.new.call(reblog.account, status) if reblog.account.local? && just_created
+    status
+  end
+
+  def object
+    @xml.at_xpath('.//activity:object', activity: TagManager::AS_XMLNS)
+  end
+
+  private
+
+  def reblog
+    return @reblog if defined? @reblog
+
+    original_status = Ostatus::Activity::Remote.new(object).perform
+    return if original_status.nil?
+
+    @reblog = original_status.reblog? ? original_status.reblog : original_status
+  end
+end
diff --git a/app/lib/atom_serializer.rb b/app/lib/ostatus/atom_serializer.rb
index b14d596ddc6..909d84df312 100644
--- a/app/lib/atom_serializer.rb
+++ b/app/lib/ostatus/atom_serializer.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AtomSerializer
+class Ostatus::AtomSerializer
   include RoutingHelper
   include ActionView::Helpers::SanitizeHelper
 
diff --git a/app/services/authorize_follow_service.rb b/app/services/authorize_follow_service.rb
index 97c76bee107..a25d11dbd51 100644
--- a/app/services/authorize_follow_service.rb
+++ b/app/services/authorize_follow_service.rb
@@ -10,6 +10,6 @@ class AuthorizeFollowService < BaseService
   private
 
   def build_xml(follow_request)
-    AtomSerializer.render(AtomSerializer.new.authorize_follow_request_salmon(follow_request))
+    Ostatus::AtomSerializer.render(Ostatus::AtomSerializer.new.authorize_follow_request_salmon(follow_request))
   end
 end
diff --git a/app/services/block_service.rb b/app/services/block_service.rb
index d59b47afbff..15420e192d2 100644
--- a/app/services/block_service.rb
+++ b/app/services/block_service.rb
@@ -18,6 +18,6 @@ class BlockService < BaseService
   private
 
   def build_xml(block)
-    AtomSerializer.render(AtomSerializer.new.block_salmon(block))
+    Ostatus::AtomSerializer.render(Ostatus::AtomSerializer.new.block_salmon(block))
   end
 end
diff --git a/app/services/concerns/stream_entry_renderer.rb b/app/services/concerns/stream_entry_renderer.rb
index ef176d8a662..d9c30c53cf3 100644
--- a/app/services/concerns/stream_entry_renderer.rb
+++ b/app/services/concerns/stream_entry_renderer.rb
@@ -2,6 +2,6 @@
 
 module StreamEntryRenderer
   def stream_entry_to_xml(stream_entry)
-    AtomSerializer.render(AtomSerializer.new.entry(stream_entry, true))
+    Ostatus::AtomSerializer.render(Ostatus::AtomSerializer.new.entry(stream_entry, true))
   end
 end
diff --git a/app/services/favourite_service.rb b/app/services/favourite_service.rb
index 90267af332a..a08aba6380b 100644
--- a/app/services/favourite_service.rb
+++ b/app/services/favourite_service.rb
@@ -28,6 +28,6 @@ class FavouriteService < BaseService
   private
 
   def build_xml(favourite)
-    AtomSerializer.render(AtomSerializer.new.favourite_salmon(favourite))
+    Ostatus::AtomSerializer.render(Ostatus::AtomSerializer.new.favourite_salmon(favourite))
   end
 end
diff --git a/app/services/follow_service.rb b/app/services/follow_service.rb
index e54ff7d0f5c..7a7275b6e72 100644
--- a/app/services/follow_service.rb
+++ b/app/services/follow_service.rb
@@ -57,10 +57,10 @@ class FollowService < BaseService
   end
 
   def build_follow_request_xml(follow_request)
-    AtomSerializer.render(AtomSerializer.new.follow_request_salmon(follow_request))
+    Ostatus::AtomSerializer.render(Ostatus::AtomSerializer.new.follow_request_salmon(follow_request))
   end
 
   def build_follow_xml(follow)
-    AtomSerializer.render(AtomSerializer.new.follow_salmon(follow))
+    Ostatus::AtomSerializer.render(Ostatus::AtomSerializer.new.follow_salmon(follow))
   end
 end
diff --git a/app/services/process_feed_service.rb b/app/services/process_feed_service.rb
index c335d21596c..b99048a068c 100644
--- a/app/services/process_feed_service.rb
+++ b/app/services/process_feed_service.rb
@@ -16,274 +16,14 @@ class ProcessFeedService < BaseService
   end
 
   def process_entries(xml, account)
-    xml.xpath('//xmlns:entry', xmlns: TagManager::XMLNS).reverse_each.map { |entry| ProcessEntry.new.call(entry, account) }.compact
+    xml.xpath('//xmlns:entry', xmlns: TagManager::XMLNS).reverse_each.map { |entry| process_entry(entry, account) }.compact
   end
 
-  class ProcessEntry
-    def call(xml, account)
-      @account = account
-      @xml     = xml
-
-      return if skip_unsupported_type?
-
-      case verb
-      when :post, :share
-        return create_status
-      when :delete
-        return delete_status
-      end
-    rescue ActiveRecord::RecordInvalid => e
-      Rails.logger.debug "Nothing was saved for #{id} because: #{e}"
-      nil
-    end
-
-    private
-
-    def create_status
-      if redis.exists("delete_upon_arrival:#{@account.id}:#{id}")
-        Rails.logger.debug "Delete for status #{id} was queued, ignoring"
-        return
-      end
-
-      status, just_created = nil
-
-      Rails.logger.debug "Creating remote status #{id}"
-
-      if verb == :share
-        original_status = shared_status_from_xml(@xml.at_xpath('.//activity:object', activity: TagManager::AS_XMLNS))
-        return nil if original_status.nil?
-      end
-
-      ApplicationRecord.transaction do
-        status, just_created = status_from_xml(@xml)
-
-        return if status.nil?
-        return status unless just_created
-
-        if verb == :share
-          status.reblog = original_status.reblog? ? original_status.reblog : original_status
-        end
-
-        status.save!
-      end
-
-      if thread?(@xml) && status.thread.nil?
-        Rails.logger.debug "Trying to attach #{status.id} (#{id(@xml)}) to #{thread(@xml).first}"
-        ThreadResolveWorker.perform_async(status.id, thread(@xml).second)
-      end
-
-      notify_about_mentions!(status) unless status.reblog?
-      notify_about_reblog!(status) if status.reblog? && status.reblog.account.local?
-
-      Rails.logger.debug "Queuing remote status #{status.id} (#{id}) for distribution"
-
-      LinkCrawlWorker.perform_async(status.id) unless status.spoiler_text?
-      DistributionWorker.perform_async(status.id)
-
-      status
-    end
-
-    def notify_about_mentions!(status)
-      status.mentions.includes(:account).each do |mention|
-        mentioned_account = mention.account
-        next unless mentioned_account.local?
-        NotifyService.new.call(mentioned_account, mention)
-      end
-    end
-
-    def notify_about_reblog!(status)
-      NotifyService.new.call(status.reblog.account, status)
-    end
-
-    def delete_status
-      Rails.logger.debug "Deleting remote status #{id}"
-      status = Status.find_by(uri: id, account: @account)
-
-      if status.nil?
-        redis.setex("delete_upon_arrival:#{@account.id}:#{id}", 6 * 3_600, id)
-      else
-        RemoveStatusService.new.call(status)
-      end
-    end
-
-    def skip_unsupported_type?
-      !([:post, :share, :delete].include?(verb) && [:activity, :note, :comment].include?(type))
-    end
-
-    def shared_status_from_xml(entry)
-      status = find_status(id(entry))
-
-      return status unless status.nil?
-
-      FetchRemoteStatusService.new.call(url(entry))
-    end
-
-    def status_from_xml(entry)
-      # Return early if status already exists in db
-      status = find_status(id(entry))
-
-      return [status, false] unless status.nil?
-
-      account = @account
-
-      return [nil, false] if account.suspended?
-
-      status = Status.create!(
-        uri: id(entry),
-        url: url(entry),
-        account: account,
-        text: content(entry),
-        spoiler_text: content_warning(entry),
-        created_at: published(entry),
-        reply: thread?(entry),
-        language: content_language(entry),
-        visibility: visibility_scope(entry),
-        conversation: find_or_create_conversation(entry),
-        thread: thread?(entry) ? find_status(thread(entry).first) : nil
-      )
-
-      mentions_from_xml(status, entry)
-      hashtags_from_xml(status, entry)
-      media_from_xml(status, entry)
-
-      [status, true]
-    end
-
-    def find_or_create_conversation(xml)
-      uri = xml.at_xpath('./ostatus:conversation', ostatus: TagManager::OS_XMLNS)&.attribute('ref')&.content
-      return if uri.nil?
-
-      if TagManager.instance.local_id?(uri)
-        local_id = TagManager.instance.unique_tag_to_local_id(uri, 'Conversation')
-        return Conversation.find_by(id: local_id)
-      end
-
-      Conversation.find_by(uri: uri) || Conversation.create!(uri: uri)
-    end
-
-    def find_status(uri)
-      if TagManager.instance.local_id?(uri)
-        local_id = TagManager.instance.unique_tag_to_local_id(uri, 'Status')
-        return Status.find_by(id: local_id)
-      end
-
-      Status.find_by(uri: uri)
-    end
-
-    def mentions_from_xml(parent, xml)
-      processed_account_ids = []
-
-      xml.xpath('./xmlns:link[@rel="mentioned"]', xmlns: TagManager::XMLNS).each do |link|
-        next if [TagManager::TYPES[:group], TagManager::TYPES[:collection]].include? link['ostatus:object-type']
-
-        mentioned_account = account_from_href(link['href'])
-
-        next if mentioned_account.nil? || processed_account_ids.include?(mentioned_account.id)
-
-        mentioned_account.mentions.where(status: parent).first_or_create(status: parent)
-
-        # So we can skip duplicate mentions
-        processed_account_ids << mentioned_account.id
-      end
-    end
-
-    def account_from_href(href)
-      url = Addressable::URI.parse(href).normalize
-
-      if TagManager.instance.web_domain?(url.host)
-        Account.find_local(url.path.gsub('/users/', ''))
-      else
-        Account.where(uri: href).or(Account.where(url: href)).first || FetchRemoteAccountService.new.call(href)
-      end
-    end
-
-    def hashtags_from_xml(parent, xml)
-      tags = xml.xpath('./xmlns:category', xmlns: TagManager::XMLNS).map { |category| category['term'] }.select(&:present?)
-      ProcessHashtagsService.new.call(parent, tags)
-    end
-
-    def media_from_xml(parent, xml)
-      do_not_download = DomainBlock.find_by(domain: parent.account.domain)&.reject_media?
-
-      xml.xpath('./xmlns:link[@rel="enclosure"]', xmlns: TagManager::XMLNS).each do |link|
-        next unless link['href']
-
-        media = MediaAttachment.where(status: parent, remote_url: link['href']).first_or_initialize(account: parent.account, status: parent, remote_url: link['href'])
-        parsed_url = Addressable::URI.parse(link['href']).normalize
-
-        next if !%w(http https).include?(parsed_url.scheme) || parsed_url.host.empty?
-
-        media.save
-
-        next if do_not_download
-
-        begin
-          media.file_remote_url = link['href']
-          media.save!
-        re