Fetch statuses/following/followers numbers from ActivityPub collections (#4840)

app/services/activitypub/process_account_service.rb

@@ -13,6 +13,7 @@ class ActivityPub::ProcessAccountService < BaseService
     @username    = username
     @domain      = domain
     @account     = Account.find_by(uri: @uri)
+    @collections = {}
 
     create_account  if @account.nil?
     upgrade_account if @account.ostatus?
@@ -51,6 +52,9 @@ class ActivityPub::ProcessAccountService < BaseService
     @account.header_remote_url   = image_url('image')
     @account.public_key          = public_key || ''
     @account.locked              = @json['manuallyApprovesFollowers'] || false
+    @account.statuses_count      = outbox_total_items    if outbox_total_items.present?
+    @account.following_count     = following_total_items if following_total_items.present?
+    @account.followers_count     = followers_total_items if followers_total_items.present?
     @account.save!
   end
 
@@ -88,6 +92,29 @@ class ActivityPub::ProcessAccountService < BaseService
     value['href']
   end
 
+  def outbox_total_items
+    collection_total_items('outbox')
+  end
+
+  def following_total_items
+    collection_total_items('following')
+  end
+
+  def followers_total_items
+    collection_total_items('followers')
+  end
+
+  def collection_total_items(type)
+    return if @json[type].blank?
+    return @collections[type] if @collections.key?(type)
+
+    collection = fetch_resource(@json[type])
+
+    @collections[type] = collection.is_a?(Hash) && collection['totalItems'].present? && collection['totalItems'].is_a?(Numeric) ? collection['totalItems'] : nil
+  rescue HTTP::Error, OpenSSL::SSL::SSLError
+    @collections[type] = nil
+  end
+
   def auto_suspend?
     domain_block && domain_block.suspend?
   end

spec/lib/activitypub/activity/update_spec.rb

@@ -4,6 +4,10 @@ RSpec.describe ActivityPub::Activity::Update do
   let!(:sender) { Fabricate(:account) }
 
   before do
+    stub_request(:get, actor_json[:outbox]).to_return(status: 404)
+    stub_request(:get, actor_json[:followers]).to_return(status: 404)
+    stub_request(:get, actor_json[:following]).to_return(status: 404)
+
     sender.update!(uri: ActivityPub::TagManager.instance.uri_for(sender))
   end