diff --git a/lib/http/request.rb b/lib/http/request.rb
index 1372cd11..a8fb2c21 100644
--- a/lib/http/request.rb
+++ b/lib/http/request.rb
@@ -49,7 +49,10 @@ class UnsupportedSchemeError < RequestError; end
       :search,
 
       # RFC 4791: Calendaring Extensions to WebDAV -- CalDAV
-      :mkcalendar
+      :mkcalendar,
+
+      # Implemented by several caching servers, like Squid, Varnish or Fastly
+      :purge
     ].freeze
 
     # Allowed schemes