Support for import/export of instance-level domain blocks/allows for 4.x w/ additional fixes (#20597)

* Allow import/export of instance-level domain blocks/allows (#1754)

* Allow import/export of instance-level domain blocks/allows.
Fixes #15095

* Pacify circleci

* Address simple code review feedback

* Add headers to exported CSV

* Extract common import/export functionality to
AdminExportControllerConcern

* Add additional fields to instance-blocked domain export

* Address review feedback

* Split instance domain block/allow import/export into separate pages/controllers

* Address code review feedback

* Pacify DeepSource

* Work around Paperclip::HasAttachmentFile for Rails 6

* Fix deprecated API warning in export tests

* Remove after_commit workaround

(cherry picked from commit 94e98864e3)

* Add confirmation page when importing blocked domains (#1773)

* Move glitch-soc-specific strings to glitch-soc-specific locale files

* Add confirmation page when importing blocked domains

(cherry picked from commit b91196f4b7)

* Fix authorization check in domain blocks controller

(cherry picked from commit 7527937758)

* Fix error strings for domain blocks and email-domain blocks

Corrected issue with non-error message used for Mastodon:NotPermittedError in Domain Blocks
Corrected issue Domain Blocks using the Email Domain Blocks message on ActionContoller::ParameterMissing
Corrected issue with Email Domain Blocks using the not_permitted string from "custom emojii's"

* Ran i18n-tasks normalize to address test failure

* Removed unused admin.export_domain_blocks.not_permitted string

Removing unused string as indicated by Check i18n

* Fix tests

(cherry picked from commit 9094c2f52c)

* Fix domain block export not exporting blocks with only media rejection

(cherry picked from commit 26ff48ee48)

* Fix various issues with domain block import

- stop using Paperclip for processing domain allow/block imports
- stop leaving temporary files
- better error handling
- assume CSV files are UTF-8-encoded

(cherry picked from commit cad824d8f5)

Co-authored-by: Levi Bard <taktaktaktaktaktaktaktaktaktak@gmail.com>
Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/controllers/admin/domain_blocks_controller.rb

@@ -4,6 +4,18 @@ module Admin
   class DomainBlocksController < BaseController
     before_action :set_domain_block, only: [:show, :destroy, :edit, :update]
 
+    def batch
+      authorize :domain_block, :create?
+      @form = Form::DomainBlockBatch.new(form_domain_block_batch_params.merge(current_account: current_account, action: action_from_button))
+      @form.save
+    rescue ActionController::ParameterMissing
+      flash[:alert] = I18n.t('admin.domain_blocks.no_domain_block_selected')
+    rescue Mastodon::NotPermittedError
+      flash[:alert] = I18n.t('admin.domain_blocks.not_permitted')
+    else
+      redirect_to admin_instances_path(limited: '1'), notice: I18n.t('admin.domain_blocks.created_msg')
+    end
+
     def new
       authorize :domain_block, :create?
       @domain_block = DomainBlock.new(domain: params[:_domain])
@@ -76,5 +88,15 @@ module Admin
     def resource_params
       params.require(:domain_block).permit(:domain, :severity, :reject_media, :reject_reports, :private_comment, :public_comment, :obfuscate)
     end
+
+    def form_domain_block_batch_params
+      params.require(:form_domain_block_batch).permit(domain_blocks_attributes: [:enabled, :domain, :severity, :reject_media, :reject_reports, :private_comment, :public_comment, :obfuscate])
+    end
+
+    def action_from_button
+      if params[:save]
+        'save'
+      end
+    end
   end
 end

app/controllers/admin/email_domain_blocks_controller.rb

@@ -19,7 +19,7 @@ module Admin
     rescue ActionController::ParameterMissing
       flash[:alert] = I18n.t('admin.email_domain_blocks.no_email_domain_block_selected')
     rescue Mastodon::NotPermittedError
-      flash[:alert] = I18n.t('admin.custom_emojis.not_permitted')
+      flash[:alert] = I18n.t('admin.email_domain_blocks.not_permitted')
     ensure
       redirect_to admin_email_domain_blocks_path
     end

app/controllers/admin/export_domain_allows_controller.rb

@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require 'csv'
+
+module Admin
+  class ExportDomainAllowsController < BaseController
+    include AdminExportControllerConcern
+
+    before_action :set_dummy_import!, only: [:new]
+
+    def new
+      authorize :domain_allow, :create?
+    end
+
+    def export
+      authorize :instance, :index?
+      send_export_file
+    end
+
+    def import
+      authorize :domain_allow, :create?
+      begin
+        @import = Admin::Import.new(import_params)
+        return render :new unless @import.validate
+
+        parse_import_data!(export_headers)
+
+        @data.take(Admin::Import::ROWS_PROCESSING_LIMIT).each do |row|
+          domain = row['#domain'].strip
+          next if DomainAllow.allowed?(domain)
+
+          domain_allow = DomainAllow.new(domain: domain)
+          log_action :create, domain_allow if domain_allow.save
+        end
+        flash[:notice] = I18n.t('admin.domain_allows.created_msg')
+      rescue ActionController::ParameterMissing
+        flash[:error] = I18n.t('admin.export_domain_allows.no_file')
+      end
+      redirect_to admin_instances_path
+    end
+
+    private
+
+    def export_filename
+      'domain_allows.csv'
+    end
+
+    def export_headers
+      %w(#domain)
+    end
+
+    def export_data
+      CSV.generate(headers: export_headers, write_headers: true) do |content|
+        DomainAllow.allowed_domains.each do |instance|
+          content << [instance.domain]
+        end
+      end
+    end
+  end
+end

app/controllers/admin/export_domain_blocks_controller.rb

@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+require 'csv'
+
+module Admin
+  class ExportDomainBlocksController < BaseController
+    include AdminExportControllerConcern
+
+    before_action :set_dummy_import!, only: [:new]
+
+    def new
+      authorize :domain_block, :create?
+    end
+
+    def export
+      authorize :instance, :index?
+      send_export_file
+    end
+
+    def import
+      authorize :domain_block, :create?
+
+      @import = Admin::Import.new(import_params)
+      return render :new unless @import.validate
+
+      parse_import_data!(export_headers)
+
+      @global_private_comment = I18n.t('admin.export_domain_blocks.import.private_comment_template', source: @import.data_file_name, date: I18n.l(Time.now.utc))
+
+      @form = Form::DomainBlockBatch.new
+      @domain_blocks = @data.take(Admin::Import::ROWS_PROCESSING_LIMIT).filter_map do |row|
+        domain = row['#domain'].strip
+        next if DomainBlock.rule_for(domain).present?
+
+        domain_block = DomainBlock.new(domain: domain,
+                                       severity: row['#severity'].strip,
+                                       reject_media: row['#reject_media'].strip,
+                                       reject_reports: row['#reject_reports'].strip,
+                                       private_comment: @global_private_comment,
+                                       public_comment: row['#public_comment']&.strip,
+                                       obfuscate: row['#obfuscate'].strip)
+
+        domain_block if domain_block.valid?
+      end
+
+      @warning_domains = Instance.where(domain: @domain_blocks.map(&:domain)).where('EXISTS (SELECT 1 FROM follows JOIN accounts ON follows.account_id = accounts.id OR follows.target_account_id = accounts.id WHERE accounts.domain = instances.domain)').pluck(:domain)
+    rescue ActionController::ParameterMissing
+      flash.now[:alert] = I18n.t('admin.export_domain_blocks.no_file')
+      set_dummy_import!
+      render :new
+    end
+
+    private
+
+    def export_filename
+      'domain_blocks.csv'
+    end
+
+    def export_headers
+      %w(#domain #severity #reject_media #reject_reports #public_comment #obfuscate)
+    end
+
+    def export_data
+      CSV.generate(headers: export_headers, write_headers: true) do |content|
+        DomainBlock.with_limitations.each do |instance|
+          content << [instance.domain, instance.severity, instance.reject_media, instance.reject_reports, instance.public_comment, instance.obfuscate]
+        end
+      end
+    end
+  end
+end

app/controllers/concerns/admin_export_controller_concern.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module AdminExportControllerConcern
+  extend ActiveSupport::Concern
+
+  private
+
+  def send_export_file
+    respond_to do |format|
+      format.csv { send_data export_data, filename: export_filename }
+    end
+  end
+
+  def export_data
+    raise 'Override in controller'
+  end
+
+  def export_filename
+    raise 'Override in controller'
+  end
+
+  def set_dummy_import!
+    @import = Admin::Import.new
+  end
+
+  def import_params
+    params.require(:admin_import).permit(:data)
+  end
+
+  def import_data_path
+    params[:admin_import][:data].path
+  end
+
+  def parse_import_data!(default_headers)
+    data = CSV.read(import_data_path, headers: true, encoding: 'UTF-8')
+    data = CSV.read(import_data_path, headers: default_headers, encoding: 'UTF-8') unless data.headers&.first&.strip&.include?(default_headers[0])
+    @data = data.reject(&:blank?)
+  end
+end

app/javascript/packs/admin.js

@@ -185,6 +185,12 @@ ready(() => {
   const registrationMode = document.getElementById('form_admin_settings_registrations_mode');
   if (registrationMode) onChangeRegistrationMode(registrationMode);
 
+  const checkAllElement = document.querySelector('#batch_checkbox_all');
+  if (checkAllElement) {
+    checkAllElement.checked = [].every.call(document.querySelectorAll(batchCheckboxClassName), (content) => content.checked);
+    checkAllElement.indeterminate = !checkAllElement.checked && [].some.call(document.querySelectorAll(batchCheckboxClassName), (content) => content.checked);
+  }
+
   document.querySelector('a#add-instance-button')?.addEventListener('click', (e) => {
     const domain = document.getElementById('by_domain')?.value;
 

app/models/admin/import.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+# A non-activerecord helper class for csv upload
+class Admin::Import
+  include ActiveModel::Model
+
+  ROWS_PROCESSING_LIMIT = 20_000
+
+  attr_accessor :data
+
+  validates :data, presence: true
+  validate :validate_data
+
+  def data_file_name
+    data.original_filename
+  end
+
+  private
+
+  def validate_data
+    return if data.blank?
+
+    csv_data = CSV.read(data.path, encoding: 'UTF-8')
+
+    row_count  = csv_data.size
+    row_count -= 1 if csv_data.first&.first == '#domain'
+
+    errors.add(:data, I18n.t('imports.errors.over_rows_processing_limit', count: ROWS_PROCESSING_LIMIT)) if row_count > ROWS_PROCESSING_LIMIT
+  rescue CSV::MalformedCSVError => e
+    errors.add(:data, I18n.t('imports.errors.invalid_csv_file', error: e.message))
+  end
+end

app/models/domain_allow.rb

@@ -28,6 +28,10 @@ class DomainAllow < ApplicationRecord
       !rule_for(domain).nil?
     end
 
+    def allowed_domains
+      select(:domain)
+    end
+
     def rule_for(domain)
       return if domain.blank?
 

app/models/domain_block.rb

@@ -29,6 +29,7 @@ class DomainBlock < ApplicationRecord
 
   scope :matches_domain, ->(value) { where(arel_table[:domain].matches("%#{value}%")) }
   scope :with_user_facing_limitations, -> { where(severity: [:silence, :suspend]) }
+  scope :with_limitations, -> { where(severity: [:silence, :suspend]).or(where(reject_media: true)) }
   scope :by_severity, -> { order(Arel.sql('(CASE severity WHEN 0 THEN 1 WHEN 1 THEN 2 WHEN 2 THEN 0 END), domain')) }
 
   def to_log_human_identifier

app/models/form/domain_block_batch.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+class Form::DomainBlockBatch
+  include ActiveModel::Model
+  include Authorization
+  include AccountableConcern
+
+  attr_accessor :domain_blocks_attributes, :action, :current_account
+
+  def save
+    case action
+    when 'save'
+      save!
+    end
+  end
+
+  private
+
+  def domain_blocks
+    @domain_blocks ||= domain_blocks_attributes.values.filter_map do |attributes|
+      DomainBlock.new(attributes.without('enabled')) if ActiveModel::Type::Boolean.new.cast(attributes['enabled'])
+    end
+  end
+
+  def save!
+    domain_blocks.each do |domain_block|
+      authorize(domain_block, :create?)
+      next if DomainBlock.rule_for(domain_block.domain).present?
+
+      domain_block.save!
+      DomainBlockWorker.perform_async(domain_block.id)
+      log_action :create, domain_block
+    end
+  end
+end

app/views/admin/export_domain_allows/new.html.haml

@@ -0,0 +1,10 @@
+- content_for :page_title do
+  = t('.title')
+
+= simple_form_for @import, url: import_admin_export_domain_allows_path, html: { multipart: true } do |f|
+  .fields-row
+    .fields-group.fields-row__column.fields-row__column-6
+      = f.input :data, wrapper: :with_block_label, hint: t('simple_form.hints.imports.data'), as: :file
+
+  .actions
+    = f.button :button, t('imports.upload'), type: :submit

app/views/admin/export_domain_blocks/_domain_block.html.haml

@@ -0,0 +1,27 @@
+- existing_relationships ||= false
+
+.batch-table__row{ class: [existing_relationships && 'batch-table__row--attention'] }
+  %label.batch-table__row__select.batch-table__row__select--aligned.batch-checkbox
+    = f.check_box :enabled, checked: !existing_relationships
+  .batch-table__row__content.pending-account
+    .pending-account__header
+      %strong
+        = f.object.domain
+      = f.hidden_field :domain
+      = f.hidden_field :severity
+      = f.hidden_field :reject_media
+      = f.hidden_field :reject_reports
+      = f.hidden_field :obfuscate
+      = f.hidden_field :private_comment
+      = f.hidden_field :public_comment
+
+      %br/
+
+      = f.object.policies.map { |policy| t(policy, scope: 'admin.instances.content_policies.policies') }.join(' • ')
+      - if f.object.public_comment.present?
+        •
+        = f.object.public_comment
+      - if existing_relationships
+        •
+        = fa_icon 'warning fw'
+        = t('admin.export_domain_blocks.import.existing_relationships_warning')

app/views/admin/export_domain_blocks/import.html.haml

@@ -0,0 +1,21 @@
+- content_for :page_title do
+  = t('admin.export_domain_blocks.import.title')
+
+%p= t('admin.export_domain_blocks.import.description_html')
+
+- if defined?(@global_private_comment) && @global_private_comment.present?
+  %p= t('admin.export_domain_blocks.import.private_comment_description_html', comment: @global_private_comment)
+
+= form_for(@form, url: batch_admin_domain_blocks_path) do |f|
+  .batch-table
+    .batch-table__toolbar
+      %label.batch-table__toolbar__select.batch-checkbox-all
+        = check_box_tag :batch_checkbox_all, nil, false
+      .batch-table__toolbar__actions
+        = f.button safe_join([fa_icon('copy'), t('admin.domain_blocks.import')]), name: :save, class: 'table-action-link', type: :submit, data: { confirm: t('admin.reports.are_you_sure') }
+    .batch-table__body
+      - if @domain_blocks.empty?
+        = nothing_here 'nothing-here--under-tabs'
+      - else
+        = f.simple_fields_for :domain_blocks, @domain_blocks do |ff|
+          = render 'domain_block', f: ff, existing_relationships: @warning_domains.include?(ff.object.domain)

app/views/admin/export_domain_blocks/new.html.haml

@@ -0,0 +1,10 @@
+- content_for :page_title do
+  = t('.title')
+
+= simple_form_for @import, url: import_admin_export_domain_blocks_path, html: { multipart: true } do |f|
+  .fields-row
+    .fields-group.fields-row__column.fields-row__column-6
+      = f.input :data, wrapper: :with_block_label, hint: t('simple_form.hints.imports.data'), as: :file
+
+  .actions
+    = f.button :button, t('imports.upload'), type: :submit

app/views/admin/instances/index.html.haml

@@ -7,8 +7,12 @@
 - content_for :heading_actions do
   - if whitelist_mode?
     = link_to t('admin.domain_allows.add_new'), new_admin_domain_allow_path, class: 'button', id: 'add-instance-button'
+    = link_to t('admin.domain_allows.export'), export_admin_export_domain_allows_path(format: :csv), class: 'button'
+    = link_to t('admin.domain_allows.import'), new_admin_export_domain_allow_path, class: 'button'
   - else
     = link_to t('admin.domain_blocks.add_new'), new_admin_domain_block_path, class: 'button', id: 'add-instance-button'
+    = link_to t('admin.domain_blocks.export'), export_admin_export_domain_blocks_path(format: :csv), class: 'button'
+    = link_to t('admin.domain_blocks.import'), new_admin_export_domain_block_path, class: 'button'
 
 .filters
   .filter-subset

config/locales/en.yml

@@ -373,6 +373,8 @@ en:
       add_new: Allow federation with domain
       created_msg: Domain has been successfully allowed for federation
       destroyed_msg: Domain has been disallowed from federation
+      export: Export
+      import: Import
       undo: Disallow federation with domain
     domain_blocks:
       add_new: Add new domain block
@@ -382,6 +384,8 @@ en:
       edit: Edit domain block
       existing_domain_block: You have already imposed stricter limits on %{name}.
       existing_domain_block_html: You have already imposed stricter limits on %{name}, you need to <a href="%{unblock_url}">unblock it</a> first.
+      export: Export
+      import: Import
       new:
         create: Create block
         hint: The domain block will not prevent creation of account entries in the database, but will retroactively and automatically apply specific moderation methods on those accounts.
@@ -391,6 +395,8 @@ en:
           silence: Limit
           suspend: Suspend
         title: New domain block
+      no_domain_block_selected: No domain blocks were changed as none were selected
+      not_permitted: You are not permitted to perform this action
       obfuscate: Obfuscate domain name
       obfuscate_hint: Partially obfuscate the domain name in the list if advertising the list of domain limitations is enabled
       private_comment: Private comment
@@ -422,6 +428,20 @@ en:
       resolved_dns_records_hint_html: The domain name resolves to the following MX domains, which are ultimately responsible for accepting e-mail. Blocking an MX domain will block sign-ups from any e-mail address which uses the same MX domain, even if the visible domain name is different. <strong>Be careful not to block major e-mail providers.</strong>
       resolved_through_html: Resolved through %{domain}
       title: Blocked e-mail domains
+    export_domain_allows:
+      new:
+        title: Import domain allows
+      no_file: No file selected
+    export_domain_blocks:
+      import:
+        description_html: You are about to import a list of domain blocks. Please review this list very carefully, especially if you have not authored this list yourself.
+        existing_relationships_warning: Existing follow relationships
+        private_comment_description_html: 'To help you track where imported blocks come from, imported blocks will be created with the following private comment: <q>%{comment}</q>'
+        private_comment_template: Imported from %{source} on %{date}
+        title: Import domain blocks
+      new:
+        title: Import domain blocks
+      no_file: No file selected
     follow_recommendations:
       description_html: "<strong>Follow recommendations help new users quickly find interesting content</strong>. When a user has not interacted with others enough to form personalized follow recommendations, these accounts are recommended instead. They are re-calculated on a daily basis from a mix of accounts with the highest recent engagements and highest local follower counts for a given language."
       language: For language
@@ -1159,6 +1179,7 @@ en:
     invalid_markup: 'contains invalid HTML markup: %{error}'
   imports:
     errors:
+      invalid_csv_file: 'Invalid CSV file. Error: %{error}'
       over_rows_processing_limit: contains more than %{count} rows
     modes:
       merge: Merge

config/routes.rb

@@ -225,7 +225,25 @@ Rails.application.routes.draw do
     get '/dashboard', to: 'dashboard#index'
 
     resources :domain_allows, only: [:new, :create, :show, :destroy]
-    resources :domain_blocks, only: [:new, :create, :destroy, :update, :edit]
+    resources :domain_blocks, only: [:new, :create, :show, :destroy, :update, :edit] do
+      collection do
+        post :batch
+      end
+    end
+
+    resources :export_domain_allows, only: [:new] do
+      collection do
+        get :export, constraints: { format: :csv }
+        post :import
+      end
+    end
+
+    resources :export_domain_blocks, only: [:new] do
+      collection do
+        get :export, constraints: { format: :csv }
+        post :import
+      end
+    end
 
     resources :email_domain_blocks, only: [:index, :new, :create] do
       collection do
@@ -523,6 +541,7 @@ Rails.application.routes.draw do
       end
 
       resource :domain_blocks, only: [:show, :create, :destroy]
+
       resource :directory, only: [:show]
 
       resources :follow_requests, only: [:index] do

spec/controllers/admin/domain_allows_controller_spec.rb

@@ -0,0 +1,48 @@
+require 'rails_helper'
+
+RSpec.describe Admin::DomainAllowsController, type: :controller do
+  render_views
+
+  before do
+    sign_in Fabricate(:user, role: UserRole.find_by(name: 'Admin')), scope: :user
+  end
+
+  describe 'GET #new' do
+    it 'assigns a new domain allow' do
+      get :new
+
+      expect(assigns(:domain_allow)).to be_instance_of(DomainAllow)
+      expect(response).to have_http_status(200)
+    end
+  end
+
+  describe 'POST #create' do
+    it 'blocks the domain when succeeded to save' do
+      post :create, params: { domain_allow: { domain: 'example.com' } }
+
+      expect(flash[:notice]).to eq I18n.t('admin.domain_allows.created_msg')
+      expect(response).to redirect_to(admin_instances_path)
+    end
+
+    it 'renders new when failed to save' do
+      Fabricate(:domain_allow, domain: 'example.com')
+
+      post :create, params: { domain_allow: { domain: 'example.com' } }
+
+      expect(response).to render_template :new
+    end
+  end
+
+  describe 'DELETE #destroy' do
+    it 'disallows the domain' do
+      service = double(call: true)
+      allow(UnallowDomainService).to receive(:new).and_return(service)
+      domain_allow = Fabricate(:domain_allow)
+      delete :destroy, params: { id: domain_allow.id }
+
+      expect(service).to have_received(:call).with(domain_allow)
+      expect(flash[:notice]).to eq I18n.t('admin.domain_allows.destroyed_msg')
+      expect(response).to redirect_to(admin_instances_path)
+    end
+  end
+end

spec/controllers/admin/domain_blocks_controller_spec.rb

@@ -16,6 +16,27 @@ RSpec.describe Admin::DomainBlocksController, type: :controller do
     end
   end
 
+  describe 'POST #batch' do
+    it 'blocks the domains when succeeded to save' do
+      allow(DomainBlockWorker).to receive(:perform_async).and_return(true)
+
+      post :batch, params: {
+        save: '',
+        form_domain_block_batch: {
+          domain_blocks_attributes: {
+            '0' => { enabled: '1', domain: 'example.com', severity: 'silence' },
+            '1' => { enabled: '0', domain: 'mastodon.social', severity: 'suspend' },
+            '2' => { enabled: '1', domain: 'mastodon.online', severity: 'suspend' }
+          }
+        }
+      }
+
+      expect(DomainBlockWorker).to have_received(:perform_async).exactly(2).times
+      expect(flash[:notice]).to eq I18n.t('admin.domain_blocks.created_msg')
+      expect(response).to redirect_to(admin_instances_path(limited: '1'))
+    end
+  end
+
   describe 'POST #create' do
     it 'blocks the domain when succeeded to save' do
       allow(DomainBlockWorker).to receive(:perform_async).and_return(true)

spec/controllers/admin/export_domain_allows_controller_spec.rb

@@ -0,0 +1,42 @@
+require 'rails_helper'
+
+RSpec.describe Admin::ExportDomainAllowsController, type: :controller do
+  render_views
+
+  before do
+    sign_in Fabricate(:user, role: UserRole.find_by(name: 'Admin')), scope: :user
+  end
+
+  describe 'GET #export' do
+    it 'renders instances' do
+      Fabricate(:domain_allow, domain: 'good.domain')
+      Fabricate(:domain_allow, domain: 'better.domain')
+
+      get :export, params: { format: :csv }
+      expect(response).to have_http_status(200)
+      expect(response.body).to eq(IO.read(File.join(file_fixture_path, 'domain_allows.csv')))
+    end
+  end
+
+  describe 'POST #import' do
+    it 'allows imported domains' do
+      post :import, params: { admin_import: { data: fixture_file_upload('domain_allows.csv') } }
+
+      expect(response).to redirect_to(admin_instances_path)
+
+      # Header should not be imported
+      expect(DomainAllow.where(domain: '#domain').present?).to eq(false)
+
+      # Domains should now be added
+      get :export, params: { format: :csv }
+      expect(response).to have_http_status(200)
+      expect(response.body).to eq(IO.read(File.join(file_fixture_path, 'domain_allows.csv')))
+    end
+
+    it 'displays error on no file selected' do
+      post :import, params: { admin_import: {} }
+      expect(response).to redirect_to(admin_instances_path)
+      expect(flash[:error]).to eq(I18n.t('admin.export_domain_allows.no_file'))
+    end
+  end
+end

spec/controllers/admin/export_domain_blocks_controller_spec.rb

@@ -0,0 +1,35 @@
+require 'rails_helper'
+
+RSpec.describe Admin::ExportDomainBlocksController, type: :controller do
+  render_views
+
+  before do
+    sign_in Fabricate(:user, role: UserRole.find_by(name: 'Admin')), scope: :user
+  end
+
+  describe 'GET #export' do
+    it 'renders instances' do
+      Fabricate(:domain_block, domain: 'bad.domain', severity: 'silence', public_comment: 'bad')
+      Fabricate(:domain_block, domain: 'worse.domain', severity: 'suspend', reject_media: true, reject_reports: true, public_comment: 'worse', obfuscate: true)
+      Fabricate(:domain_block, domain: 'reject.media', severity: 'noop', reject_media: true, public_comment: 'reject media')
+      Fabricate(:domain_block, domain: 'no.op', severity: 'noop', public_comment: 'noop')
+
+      get :export, params: { format: :csv }
+      expect(response).to have_http_status(200)
+      expect(response.body).to eq(IO.read(File.join(file_fixture_path, 'domain_blocks.csv')))
+    end
+  end
+
+  describe 'POST #import' do
+    it 'blocks imported domains' do
+      post :import, params: { admin_import: { data: fixture_file_upload('domain_blocks.csv') } }
+
+      expect(assigns(:domain_blocks).map(&:domain)).to match_array ['bad.domain', 'worse.domain', 'reject.media']
+    end
+  end
+
+  it 'displays error on no file selected' do
+    post :import, params: { admin_import: {} }
+    expect(flash[:alert]).to eq(I18n.t('admin.export_domain_blocks.no_file'))
+  end
+end

spec/fixtures/files/domain_allows.csv

@@ -0,0 +1,3 @@
+#domain
+good.domain
+better.domain

spec/fixtures/files/domain_blocks.csv

@@ -0,0 +1,4 @@
+#domain,#severity,#reject_media,#reject_reports,#public_comment,#obfuscate
+bad.domain,silence,false,false,bad,false
+worse.domain,suspend,true,true,worse,true
+reject.media,noop,true,false,reject media,false