Add public blocks to /about/blocks (#11298)

* Add automatic blocklist display in /about/blocks

Inspired by https://github.com/Gargron/mastodon.social-misc

* Add admin option to set who can see instance blocks

* Normalize locales files

* Rename “Sandbox” to “Silence” for consistency

* Disable /about/blocks when in whitelist mode

* Optionally display rationale for domain blocks

* Only display domain blocks that have user-facing limitations, and order them

* Redesign table of blocked domains to better handle long domain names and rationales

* Change domain blocks ordering now that rationales aren't displayed right away

* Only show explanation for block severities actually in use

* Reword instance block explanations and add disclaimer for public fetch mode

1 files changed, 32 insertions, 2 deletions

diff --git a/app/controllers/about_controller.rb b/app/controllers/about_controller.rb
index d276e8fe5..5e942e5c0 100644
--- a/app/controllers/about_controller.rb
+++ b/app/controllers/about_controller.rb
@@ -3,10 +3,12 @@
 class AboutController < ApplicationController
   layout 'public'
 
-  before_action :require_open_federation!, only: [:show, :more]
+  before_action :require_open_federation!, only: [:show, :more, :blocks]
+  before_action :check_blocklist_enabled, only: [:blocks]
+  before_action :authenticate_user!, only: [:blocks], if: :blocklist_account_required?
   before_action :set_body_classes, only: :show
   before_action :set_instance_presenter
-  before_action :set_expires_in
+  before_action :set_expires_in, only: [:show, :more, :terms]
 
   skip_before_action :require_functional!, only: [:more, :terms]
 
@@ -18,12 +20,40 @@ class AboutController < ApplicationController
 
   def terms; end
 
+  def blocks
+    @show_rationale = Setting.show_domain_blocks_rationale == 'all'
+    @show_rationale |= Setting.show_domain_blocks_rationale == 'users' && !current_user.nil? && current_user.functional?
+    @blocks = DomainBlock.with_user_facing_limitations.order('(CASE severity WHEN 0 THEN 1 WHEN 1 THEN 2 WHEN 2 THEN 0 END), reject_media, domain').to_a
+  end
+
   private
 
   def require_open_federation!
     not_found if whitelist_mode?
   end
 
+  def check_blocklist_enabled
+    not_found if Setting.show_domain_blocks == 'disabled'
+  end
+
+  def blocklist_account_required?
+    Setting.show_domain_blocks == 'users'
+  end
+
+  def block_severity_text(block)
+    if block.severity == 'suspend'
+      I18n.t('domain_blocks.suspension')
+    else
+      limitations = []
+      limitations << I18n.t('domain_blocks.media_block') if block.reject_media?
+      limitations << I18n.t('domain_blocks.silence') if block.severity == 'silence'
+      limitations.join(', ')
+    end
+  end
+
+  helper_method :block_severity_text
+  helper_method :public_fetch_mode?
+
   def new_user
     User.new.tap do |user|
       user.build_account