Redirect with interstitial when trying to view a remote collection while logged out (#38941)

app/controllers/redirect/collections_controller.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class Redirect::CollectionsController < Redirect::BaseController
+  private
+
+  def set_resource
+    @resource = Collection.find(params[:id])
+    not_found if @resource.local? || @resource&.account&.suspended?
+  end
+end

app/lib/permalink_redirector.rb

@@ -21,6 +21,9 @@ class PermalinkRedirector
       elsif accounts_request? && record_integer_id_request?
         account = Account.find_by(id: second_segment)
         account if !account&.local? && !account&.suspended?
+      elsif collections_request? && record_integer_id_request?
+        collection = Collection.find_by(id: second_segment)
+        collection if !collection&.local? && !collection&.account&.suspended?
       end
     end
   end
@@ -43,6 +46,8 @@ class PermalinkRedirector
       redirect_account_path(object.id)
     when 'Status'
       redirect_status_path(object.id)
+    when 'Collection'
+      redirect_collection_path(object.id)
     else
       @path.delete_prefix('/deck') if @path.start_with?('/deck')
     end
@@ -70,6 +75,10 @@ class PermalinkRedirector
     first_segment == 'accounts'
   end
 
+  def collections_request?
+    first_segment == 'collections'
+  end
+
   def record_integer_id_request?
     second_segment =~ /\d/
   end