Add option to obfuscate domain name in public list of domain blocks

app/controllers/admin/domain_blocks_controller.rb

@@ -74,11 +74,11 @@ def set_domain_block
     end
 
     def update_params
-      params.require(:domain_block).permit(:severity, :reject_media, :reject_reports, :private_comment, :public_comment)
+      params.require(:domain_block).permit(:severity, :reject_media, :reject_reports, :private_comment, :public_comment, :obfuscate)
     end
 
     def resource_params
-      params.require(:domain_block).permit(:domain, :severity, :reject_media, :reject_reports, :private_comment, :public_comment)
+      params.require(:domain_block).permit(:domain, :severity, :reject_media, :reject_reports, :private_comment, :public_comment, :obfuscate)
     end
   end
 end

app/models/domain_block.rb

@@ -12,6 +12,7 @@
 #  reject_reports  :boolean          default(FALSE), not null
 #  private_comment :text
 #  public_comment  :text
+#  obfuscate       :boolean          default(FALSE), not null
 #
 
 class DomainBlock < ApplicationRecord
@@ -73,4 +74,23 @@ def affected_accounts_count
     scope = suspend? ? accounts.where(suspended_at: created_at) : accounts.where(silenced_at: created_at)
     scope.count
   end
+
+  def public_domain
+    return domain unless obfuscate?
+
+    length        = domain.size
+    visible_ratio = length / 4
+
+    domain.chars.map.with_index do |chr, i|
+      if i > visible_ratio && i < length - visible_ratio && chr != '.'
+        '*'
+      else
+        chr
+      end
+    end.join
+  end
+
+  def domain_digest
+    Digest::SHA256.hexdigest(domain)
+  end
 end

app/views/about/_domain_blocks.html.haml

@@ -7,6 +7,6 @@
     - domain_blocks.each do |domain_block|
       %tr
         %td.nowrap
-          %span{ title: domain_block.domain }= domain_block.domain
+          %span{ title: "SHA-256: #{domain_block.domain_digest}" }= domain_block.public_domain
         %td
           = domain_block.public_comment if display_blocks_rationale?

app/views/admin/domain_blocks/edit.html.haml

@@ -20,6 +20,9 @@
   .fields-group
     = f.input :reject_reports, as: :boolean, wrapper: :with_label, label: I18n.t('admin.domain_blocks.reject_reports'), hint: I18n.t('admin.domain_blocks.reject_reports_hint')
 
+  .fields-group
+    = f.input :obfuscate, as: :boolean, wrapper: :with_label, label: I18n.t('admin.domain_blocks.obfuscate'), hint: I18n.t('admin.domain_blocks.obfuscate_hint')
+
   .field-group
     = f.input :private_comment, wrapper: :with_label, label: I18n.t('admin.domain_blocks.private_comment'), hint: t('admin.domain_blocks.private_comment_hint'), rows: 6
 

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

@@ -20,6 +20,9 @@
   .fields-group
     = f.input :reject_reports, as: :boolean, wrapper: :with_label, label: I18n.t('admin.domain_blocks.reject_reports'), hint: I18n.t('admin.domain_blocks.reject_reports_hint')
 
+  .fields-group
+    = f.input :obfuscate, as: :boolean, wrapper: :with_label, label: I18n.t('admin.domain_blocks.obfuscate'), hint: I18n.t('admin.domain_blocks.obfuscate_hint')
+
   .field-group
     = f.input :private_comment, wrapper: :with_label, label: I18n.t('admin.domain_blocks.private_comment'), hint: t('admin.domain_blocks.private_comment_hint'), rows: 6
 

config/locales/en.yml

@@ -402,6 +402,8 @@ en:
           silence: Silence
           suspend: Suspend
         title: New domain block
+      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
       private_comment_hint: Comment about this domain limitation for internal use by the moderators.
       public_comment: Public comment

db/migrate/20201218054746_add_obfuscate_to_domain_blocks.rb

@@ -0,0 +1,15 @@
+require Rails.root.join('lib', 'mastodon', 'migration_helpers')
+
+class AddObfuscateToDomainBlocks < ActiveRecord::Migration[5.2]
+  include Mastodon::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  def up
+    safety_assured { add_column_with_default :domain_blocks, :obfuscate, :boolean, default: false, allow_null: false }
+  end
+
+  def down
+    remove_column :domain_blocks, :obfuscate
+  end
+end

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: 2020_12_06_004238) do
+ActiveRecord::Schema.define(version: 2020_12_18_054746) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -360,6 +360,7 @@
     t.boolean "reject_reports", default: false, null: false
     t.text "private_comment"
     t.text "public_comment"
+    t.boolean "obfuscate", default: false, null: false
     t.index ["domain"], name: "index_domain_blocks_on_domain", unique: true
   end