Made some progress

app/helpers/application_helper.rb

@@ -1,2 +1,19 @@
 module ApplicationHelper
+  include GrapeRouteHelpers::NamedRouteMatcher
+
+  def unique_tag(date, id, type)
+    "tag:#{LOCAL_DOMAIN},#{date.strftime('%Y-%m-%d')}:objectId=#{id}:objectType=#{type}"
+  end
+
+  def subscription_url(account)
+    add_base_url_prefix subscription_path(id: account.id, format: '')
+  end
+
+  def salmon_url(account)
+    add_base_url_prefix salmon_path(id: account.id, format: '')
+  end
+
+  def add_base_url_prefix(suffix)
+    "#{root_url}api#{suffix}"
+  end
 end

app/helpers/atom_helper.rb

@@ -0,0 +1,5 @@
+module AtomHelper
+  def stream_updated_at
+    @account.stream_entries.last ? @account.stream_entries.last.created_at.iso8601 : @account.updated_at.iso8601
+  end
+end

app/helpers/home_helper.rb

@@ -0,0 +1,2 @@
+module HomeHelper
+end

app/helpers/profile_helper.rb

@@ -0,0 +1,2 @@
+module ProfileHelper
+end

app/helpers/xrd_helper.rb

@@ -0,0 +1,2 @@
+module XrdHelper
+end