Account archive download (#6460)

* Fix #201: Account archive download

* Export actor and private key in the archive

* Optimize BackupService

- Add conversation to cached associations of status, because
  somehow it was forgotten and is source of N+1 queries
- Explicitly call GC between batches of records being fetched
  (Model class allocations are the worst offender)
- Stream media files into the tar in 1MB chunks
  (Do not allocate media file (up to 8MB) as string into memory)
- Use #bytesize instead of #size to calculate file size for JSON
  (Fix FileOverflow error)
- Segment media into subfolders by status ID because apparently
  GIF-to-MP4 media are all named "media.mp4" for some reason

* Keep uniquely generated filename in Paperclip::GifTranscoder

* Ensure dumped files do not overwrite each other by maintaing directory partitions

* Give tar archives a good name

* Add scheduler to remove week-old backups

* Fix code style issue

27 files changed, 374 insertions, 7 deletions

diff --git a/Gemfile b/Gemfile
index ad1598af31a..da5fc2f38ba 100644
--- a/Gemfile
+++ b/Gemfile
@@ -116,6 +116,7 @@ group :development do
   gem 'bullet', '~> 5.5'
   gem 'letter_opener', '~> 1.4'
   gem 'letter_opener_web', '~> 1.3'
+  gem 'memory_profiler'
   gem 'rubocop', require: false
   gem 'brakeman', '~> 4.0', require: false
   gem 'bundler-audit', '~> 0.6', require: false
diff --git a/Gemfile.lock b/Gemfile.lock
index 920262ededb..65a0dfabfdf 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -301,6 +301,7 @@ GEM
       mini_mime (>= 0.1.1)
     mario-redis-lock (1.2.0)
       redis (~> 3, >= 3.0.5)
+    memory_profiler (0.9.10)
     method_source (0.9.0)
     microformats (4.0.7)
       json
@@ -664,6 +665,7 @@ DEPENDENCIES
   link_header (~> 0.0)
   lograge (~> 0.7)
   mario-redis-lock (~> 1.2)
+  memory_profiler
   microformats (~> 4.0)
   mime-types (~> 3.1)
   nokogiri (~> 1.8)
diff --git a/app/controllers/settings/exports_controller.rb b/app/controllers/settings/exports_controller.rb
index ae62f00c1e2..869e11d3bf6 100644
--- a/app/controllers/settings/exports_controller.rb
+++ b/app/controllers/settings/exports_controller.rb
@@ -1,11 +1,23 @@
 # frozen_string_literal: true
 
 class Settings::ExportsController < ApplicationController
+  include Authorization
+
   layout 'admin'
 
   before_action :authenticate_user!
 
   def show
-    @export = Export.new(current_account)
+    @export  = Export.new(current_account)
+    @backups = current_user.backups
+  end
+
+  def create
+    authorize :backup, :create?
+
+    backup = current_user.backups.create!
+    BackupWorker.perform_async(backup.id)
+
+    redirect_to settings_export_path
   end
 end
diff --git a/app/javascript/images/icon_file_download.svg b/app/javascript/images/icon_file_download.svg
new file mode 100644
index 00000000000..53e97e4f8af
--- /dev/null
+++ b/app/javascript/images/icon_file_download.svg
@@ -0,0 +1,4 @@
+<svg fill="#FFFFFF" height="24" viewBox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg">
+    <path d="M19 9h-4V3H9v6H5l7 7 7-7zM5 18v2h14v-2H5z"/>
+    <path d="M0 0h24v24H0z" fill="none"/>
+</svg>
\ No newline at end of file
diff --git a/app/javascript/images/mailer/icon_file_download.png b/app/javascript/images/mailer/icon_file_download.png
new file mode 100644
index 00000000000..8a6a8673bcb
--- /dev/null
+++ b/app/javascript/images/mailer/icon_file_download.png
diff --git a/app/mailers/user_mailer.rb b/app/mailers/user_mailer.rb
index 2fc9caba3f9..9848c34a25e 100644
--- a/app/mailers/user_mailer.rb
+++ b/app/mailers/user_mailer.rb
@@ -66,4 +66,16 @@ class UserMailer < Devise::Mailer
       mail to: @resource.email, subject: I18n.t('user_mailer.welcome.subject')
     end
   end
+
+  def backup_ready(user, backup)
+    @resource = user
+    @instance = Rails.configuration.x.local_domain
+    @backup   = backup
+
+    return if @resource.disabled?
+
+    I18n.with_locale(@resource.locale || I18n.default_locale) do
+      mail to: @resource.email, subject: I18n.t('user_mailer.backup_ready.subject')
+    end
+  end
 end
diff --git a/app/models/backup.rb b/app/models/backup.rb
new file mode 100644
index 00000000000..5a7e6a14d5f
--- /dev/null
+++ b/app/models/backup.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+# == Schema Information
+#
+# Table name: backups
+#
+#  id                :integer          not null, primary key
+#  user_id           :integer
+#  dump_file_name    :string
+#  dump_content_type :string
+#  dump_file_size    :integer
+#  dump_updated_at   :datetime
+#  processed         :boolean          default(FALSE), not null
+#  created_at        :datetime         not null
+#  updated_at        :datetime         not null
+#
+
+class Backup < ApplicationRecord
+  belongs_to :user, inverse_of: :backups
+
+  has_attached_file :dump
+  do_not_validate_attachment_file_type :dump
+end
diff --git a/app/models/status.rb b/app/models/status.rb
index 8186f478492..f806a59fcb3 100644
--- a/app/models/status.rb
+++ b/app/models/status.rb
@@ -76,7 +76,7 @@ class Status < ApplicationRecord
   scope :not_excluded_by_account, ->(account) { where.not(account_id: account.excluded_from_timeline_account_ids) }
   scope :not_domain_blocked_by_account, ->(account) { account.excluded_from_timeline_domains.blank? ? left_outer_joins(:account) : left_outer_joins(:account).where('accounts.domain IS NULL OR accounts.domain NOT IN (?)', account.excluded_from_timeline_domains) }
 
-  cache_associated :account, :application, :media_attachments, :tags, :stream_entry, mentions: :account, reblog: [:account, :application, :stream_entry, :tags, :media_attachments, mentions: :account], thread: :account
+  cache_associated :account, :application, :media_attachments, :conversation, :tags, :stream_entry, mentions: :account, reblog: [:account, :application, :stream_entry, :tags, :media_attachments, :conversation, mentions: :account], thread: :account
 
   delegate :domain, to: :account, prefix: true
 
diff --git a/app/models/user.rb b/app/models/user.rb
index fd153912e64..fcd574f8bda 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -60,6 +60,7 @@ class User < ApplicationRecord
   accepts_nested_attributes_for :account
 
   has_many :applications, class_name: 'Doorkeeper::Application', as: :owner
+  has_many :backups, inverse_of: :user
 
   validates :locale, inclusion: I18n.available_locales.map(&:to_s), if: :locale?
   validates_with BlacklistedEmailValidator, if: :email_changed?
diff --git a/app/policies/application_policy.rb b/app/policies/application_policy.rb
index 3e617001fa4..d1de5e81a21 100644
--- a/app/policies/application_policy.rb
+++ b/app/policies/application_policy.rb
@@ -15,4 +15,8 @@ class ApplicationPolicy
   def current_user
     current_account&.user
   end
+
+  def user_signed_in?
+    !current_user.nil?
+  end
 end
diff --git a/app/policies/backup_policy.rb b/app/policies/backup_policy.rb
new file mode 100644
index 00000000000..0ef89a8d0c8
--- /dev/null
+++ b/app/policies/backup_policy.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class BackupPolicy < ApplicationPolicy
+  MIN_AGE = 1.week
+
+  def create?
+    user_signed_in? && current_user.backups.where('created_at >= ?', MIN_AGE.ago).count.zero?
+  end
+end
diff --git a/app/serializers/activitypub/collection_serializer.rb b/app/serializers/activitypub/collection_serializer.rb
index 9832133fc0c..d43af3f8e39 100644
--- a/app/serializers/activitypub/collection_serializer.rb
+++ b/app/serializers/activitypub/collection_serializer.rb
@@ -13,8 +13,8 @@ class ActivityPub::CollectionSerializer < ActiveModel::Serializer
   attribute :part_of, if: -> { object.part_of.present? }
 
   has_one :first, if: -> { object.first.present? }
-  has_many :items, key: :items, if: -> { (object.items.present? || page?) && !ordered? }
-  has_many :items, key: :ordered_items, if: -> { (object.items.present? || page?) && ordered? }
+  has_many :items, key: :items, if: -> { (!object.items.nil? || page?) && !ordered? }
+  has_many :items, key: :ordered_items, if: -> { (!object.items.nil? || page?) && ordered? }
 
   def type
     if page?
diff --git a/app/services/backup_service.rb b/app/services/backup_service.rb
new file mode 100644
index 00000000000..fadc24a82c7
--- /dev/null
+++ b/app/services/backup_service.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+require 'rubygems/package'
+
+class BackupService < BaseService
+  attr_reader :account, :backup, :collection
+
+  def call(backup)
+    @backup  = backup
+    @account = backup.user.account
+
+    build_json!
+    build_archive!
+  end
+
+  private
+
+  def build_json!
+    @collection = serialize(collection_presenter, ActivityPub::CollectionSerializer)
+
+    account.statuses.with_includes.find_in_batches do |statuses|
+      statuses.each do |status|
+        item = serialize(status, ActivityPub::ActivitySerializer)
+        item.delete(:'@context')
+
+        unless item[:type] == 'Announce' || item[:object][:attachment].blank?
+          item[:object][:attachment].each do |attachment|
+            attachment[:url] = Addressable::URI.parse(attachment[:url]).path.gsub(/\A\/system\//, '')
+          end
+        end
+
+        @collection[:orderedItems] << item
+      end
+
+      GC.start
+    end
+  end
+
+  def build_archive!
+    tmp_file = Tempfile.new(%w(archive .tar.gz))
+
+    File.open(tmp_file, 'wb') do |file|
+      Zlib::GzipWriter.wrap(file) do |gz|
+        Gem::Package::TarWriter.new(gz) do |tar|
+          dump_media_attachments!(tar)
+          dump_outbox!(tar)
+          dump_actor!(tar)
+        end
+      end
+    end
+
+    archive_filename = ['archive', Time.now.utc.strftime('%Y%m%d%H%M%S'), SecureRandom.hex(2)].join('-') + '.tar.gz'
+
+    @backup.dump      = ActionDispatch::Http::UploadedFile.new(tempfile: tmp_file, filename: archive_filename)
+    @backup.processed = true
+    @backup.save!
+  ensure
+    tmp_file.close
+    tmp_file.unlink
+  end
+
+  def dump_media_attachments!(tar)
+    MediaAttachment.attached.where(account: account).find_in_batches do |media_attachments|
+      media_attachments.each do |m|
+        download_to_tar(tar, m.file, m.file.path)
+      end
+
+      GC.start
+    end
+  end
+
+  def dump_outbox!(tar)
+    json = Oj.dump(collection)
+
+    tar.add_file_simple('outbox.json', 0o444, json.bytesize) do |io|
+      io.write(json)
+    end
+  end
+
+  def dump_actor!(tar)
+    actor = serialize(account, ActivityPub::ActorSerializer)
+
+    actor[:icon][:url]  = 'avatar' + File.extname(actor[:icon][:url])  if actor[:icon]
+    actor[:image][:url] = 'header' + File.extname(actor[:image][:url]) if actor[:image]
+
+    download_to_tar(tar, account.avatar, 'avatar' + File.extname(account.avatar.path)) if account.avatar.exists?
+    download_to_tar(tar, account.header, 'header' + File.extname(account.header.path)) if account.header.exists?
+
+    json = Oj.dump(actor)
+
+    tar.add_file_simple('actor.json', 0o444, json.bytesize) do |io|
+      io.write(json)
+    end
+
+    tar.add_file_simple('key.pem', 0o444, account.private_key.bytesize) do |io|
+      io.write(account.private_key)
+    end
+  end
+
+  def collection_presenter
+    ActivityPub::CollectionPresenter.new(
+      id: account_outbox_url(account),
+      type: :ordered,
+      size: account.statuses_count,
+      items: []
+    )
+  end
+
+  def serialize(object, serializer)
+    ActiveModelSerializers::SerializableResource.new(
+      object,
+      serializer: serializer,
+      adapter: ActivityPub::Adapter
+    ).as_json
+  end
+
+  CHUNK_SIZE = 1.megabyte
+
+  def download_to_tar(tar, attachment, filename)
+    adapter = Paperclip.io_adapters.for(attachment)
+
+    tar.add_file_simple(filename, 0o444, adapter.size) do |io|
+      while (buffer = adapter.read(CHUNK_SIZE))
+        io.write(buffer)
+      end
+    end
+  end
+end
diff --git a/app/views/settings/exports/show.html.haml b/app/views/settings/exports/show.html.haml
index e0df1c48023..89d768d3fcf 100644
--- a/app/views/settings/exports/show.html.haml
+++ b/app/views/settings/exports/show.html.haml
@@ -20,3 +20,26 @@
         %th= t('exports.mutes')
         %td= @export.total_mutes
         %td= table_link_to 'download', t('exports.csv'), settings_exports_mutes_path(format: :csv)
+
+%p.muted-hint= t('exports.archive_takeout.hint_html')
+
+- if policy(:backup).create?
+  %p= link_to t('exports.archive_takeout.request'), settings_export_path, class: 'button', method: :post
+
+- unless @backups.empty?
+  .table-wrapper
+    %table.table
+      %thead
+        %tr
+          %th= t('exports.archive_takeout.date')
+          %th= t('exports.archive_takeout.size')
+          %th
+      %tbody
+        - @backups.each do |backup|
+          %tr
+            %td= l backup.created_at
+            - if backup.processed?
+              %td= number_to_human_size backup.dump_file_size
+              %td= table_link_to 'download', t('exports.archive_takeout.download'), backup.dump.url
+            - else
+              %td{ colspan: 2 }= t('exports.archive_takeout.in_progress')
diff --git a/app/views/user_mailer/backup_ready.html.haml b/app/views/user_mailer/backup_ready.html.haml
new file mode 100644
index 00000000000..d5a4b8b48b6
--- /dev/null
+++ b/app/views/user_mailer/backup_ready.html.haml
@@ -0,0 +1,59 @@
+%table.email-table{ cellspacing: 0, cellpadding: 0 }
+  %tbody
+    %tr
+      %td.email-body
+        .email-container
+          %table.content-section{ cellspacing: 0, cellpadding: 0 }
+            %tbody
+              %tr
+                %td.content-cell.hero
+                  .email-row
+                    .col-6
+                      %table.column{ cellspacing: 0, cellpadding: 0 }
+                        %tbody
+                          %tr
+                            %td.column-cell.text-center.padded
+                              %table.hero-icon{ align: 'center', cellspacing: 0, cellpadding: 0 }
+                                %tbody
+                                  %tr
+                                    %td
+                                      = image_tag full_pack_url('icon_file_download.png'), alt: ''
+
+                              %h1= t 'user_mailer.backup_ready.title'
+
+%table.email-table{ cellspacing: 0, cellpadding: 0 }
+  %tbody
+    %tr
+      %td.email-body
+        .email-container
+          %table.content-section{ cellspacing: 0, cellpadding: 0 }
+            %tbody
+              %tr
+                %td.content-cell.content-start
+                  .email-row
+                    .col-6
+                      %table.column{ cellspacing: 0, cellpadding: 0 }
+                        %tbody
+                          %tr
+                            %td.column-cell.text-center
+                              %p= t 'user_mailer.backup_ready.explanation'
+
+%table.email-table{ cellspacing: 0, cellpadding: 0 }
+  %tbody
+    %tr
+      %td.email-body
+        .email-container
+          %table.content-section{ cellspacing: 0, cellpadding: 0 }
+            %tbody
+              %tr
+                %td.content-cell
+                  %table.column{ cellspacing: 0, cellpadding: 0 }
+                    %tbody
+                      %tr
+                        %td.column-cell.button-cell
+                          %table.button{ align: 'center', cellspacing: 0, cellpadding: 0 }
+                            %tbody
+                              %tr
+                                %td.button-primary
+                                  = link_to full_asset_url(@backup.dump.url) do
+                                    %span= t 'exports.archive_takeout.download'
diff --git a/app/views/user_mailer/backup_ready.text.erb b/app/views/user_mailer/backup_ready.text.erb
new file mode 100644
index 00000000000..eb89e7d743f
--- /dev/null
+++ b/app/views/user_mailer/backup_ready.text.erb
@@ -0,0 +1,7 @@
+<%= t 'user_mailer.backup_ready.title' %>
+
+===
+
+<%= t 'user_mailer.backup_ready.explanation' %>
+
+=> <%= full_asset_url(@backup.dump.url) %>
diff --git a/app/workers/backup_worker.rb b/app/workers/backup_worker.rb
new file mode 100644
index 00000000000..ec6db4e9e3f
--- /dev/null
+++ b/app/workers/backup_worker.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class BackupWorker
+  include Sidekiq::Worker
+
+  sidekiq_options queue: 'pull'
+
+  def perform(backup_id)
+    backup = Backup.find(backup_id)
+    user   = backup.user
+
+    BackupService.new.call(backup)
+
+    user.backups.where.not(id: backup.id).destroy_all
+    UserMailer.backup_ready(user, backup).deliver_later
+  end
+end
diff --git a/app/workers/scheduler/backup_cleanup_scheduler.rb b/app/workers/scheduler/backup_cleanup_scheduler.rb
new file mode 100644
index 00000000000..7a9d4f894f9
--- /dev/null
+++ b/app/workers/scheduler/backup_cleanup_scheduler.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+require 'sidekiq-scheduler'
+
+class Scheduler::BackupCleanupScheduler
+  include Sidekiq::Worker
+
+  def perform
+    old_backups.find_each(&:destroy!)
+  end
+
+  private
+
+  def old_backups
+    Backup.where('created_at < ?', 7.days.ago)
+  end
+end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 5cd3b08cf0a..b9dd5bd51fb 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -421,6 +421,13 @@ en:
       title: This page is not correct
     noscript_html: To use the Mastodon web application, please enable JavaScript. Alternatively, try one of the <a href="https://github.com/tootsuite/documentation/blob/master/Using-Mastodon/Apps.md">native apps</a> for Mastodon for your platform.
   exports:
+    archive_takeout:
+      date: Date
+      download: Download your archive
+      hint_html: You can request an archive of your <strong>toots and uploaded media</strong>. The exported data will be in ActivityPub format, readable by any compliant software.
+      in_progress: Compiling your archive...
+      request: Request your archive
+      size: Size
     blocks: You block
     csv: CSV
     follows: You follow
@@ -733,6 +740,10 @@ en:
     setup: Set up
     wrong_code: The entered code was invalid! Are server time and device time correct?
   user_mailer:
+    backup_ready:
+      explanation: You requested a full backup of your Mastodon account. It's now ready for download!
+      subject: Your archive is ready for download
+      title: Archive takeout
     welcome:
       edit_profile_action: Setup profile
       edit_profile_step: You can customize your profile by uploading an avatar, header, changing your display name and more. If you’d like to review new followers before they’re allowed to follow you, you can lock your account.
diff --git a/config/routes.rb b/config/routes.rb
index 9f541200a23..7ed2d61f1bf 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -76,7 +76,7 @@ Rails.application.routes.draw do
     resource :notifications, only: [:show, :update]
     resource :import, only: [:show, :create]
 
-    resource :export, only: [:show]
+    resource :export, only: [:show, :create]
     namespace :exports, constraints: { format: :csv } do
       resources :follows, only: :index, controller: :following_accounts
       resources :blocks, only: :index, controller: :blocked_accounts
diff --git a/config/sidekiq.yml b/config/sidekiq.yml
index bfe29b8f818..244e9ea48b4 100644
--- a/config/sidekiq.yml
+++ b/config/sidekiq.yml
@@ -30,3 +30,6 @@
   email_scheduler:
     cron: '0 10 * * 2'
     class: Scheduler::EmailScheduler
+  backup_cleanup_scheduler:
+    cron: '<%= Random.rand(0..59) %> <%= Random.rand(3..5) %> * * *'
+    class: Scheduler::BackupCleanupScheduler
diff --git a/db/migrate/20180211015820_create_backups.rb b/db/migrate/20180211015820_create_backups.rb
new file mode 100644
index 00000000000..9725a3e9f37
--- /dev/null
+++ b/db/migrate/20180211015820_create_backups.rb
@@ -0,0 +1,11 @@
+class CreateBackups < ActiveRecord::Migration[5.1]
+  def change
+    create_table :backups do |t|
+      t.references :user, foreign_key: { on_delete: :nullify }
+      t.attachment :dump
+      t.boolean :processed, null: false, default: false
+
+      t.timestamps
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 281110124e0..213fbc8d9a4 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180206000000) do
+ActiveRecord::Schema.define(version: 20180211015820) do
 
   # These are extensions that must be enabled in order to support this database
   enable_ex