Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `README.md`:
  Upstream changed their README, we have our own.
  Kept ours.
- `app/helpers/application_helper.rb`:
  Minor code style fix upstream, on a line that is different in glitch-soc
  due to the different theming system.
  Applied the code style fix to our own code.
- `app/views/settings/preferences/appearance/show.html.haml`:
  Code style fix on a line next to lines exclusive to glitch-soc.
  Applied upstream changes.
- `yarn.lock`:
  Upstream updated a dependency textually close to a glitch-soc-only
  dependency.
  Updated the dependency like upstream did.

app/controllers/api/v1/instances/translation_languages_controller.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class Api::V1::Instances::TranslationLanguagesController < Api::BaseController
+  skip_before_action :require_authenticated_user!, unless: :whitelist_mode?
+
+  before_action :set_languages
+
+  def show
+    expires_in 1.day, public: true
+    render json: @languages
+  end
+
+  private
+
+  def set_languages
+    if TranslationService.configured?
+      @languages = Rails.cache.fetch('translation_service/languages', expires_in: 7.days, race_condition_ttl: 1.hour) { TranslationService.configured.languages }
+      @languages['und'] = @languages.delete(nil) if @languages.key?(nil)
+    else
+      @languages = {}
+    end
+  end
+end

app/controllers/backups_controller.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+class BackupsController < ApplicationController
+  include RoutingHelper
+
+  skip_before_action :require_functional!
+
+  before_action :authenticate_user!
+  before_action :set_backup
+
+  def download
+    case Paperclip::Attachment.default_options[:storage]
+    when :s3
+      redirect_to @backup.dump.expiring_url(10)
+    when :fog
+      redirect_to @backup.dump.expiring_url(Time.now.utc + 10)
+    when :filesystem
+      redirect_to full_asset_url(@backup.dump.url)
+    end
+  end
+
+  private
+
+  def set_backup
+    @backup = current_user.backups.find(params[:id])
+  end
+end

app/controllers/concerns/signature_verification.rb

@@ -138,7 +138,7 @@ module SignatureVerification
   end
 
   def signed_headers
-    signature_params.fetch('headers', signature_algorithm == 'hs2019' ? '(created)' : 'date').downcase.split(' ')
+    signature_params.fetch('headers', signature_algorithm == 'hs2019' ? '(created)' : 'date').downcase.split
   end
 
   def verify_signature_strength!