lighttpd.conf

$HTTP["host"] =~ "xmarks.foobar.com" {
  server.document-root = "/path/to/xmarks/dir"
  webdav.activate = "enable"
  webdav.is-readonly = "disable"
  webdav.sqlite-db-name = "/var/run/lighttpd/lighttpd.webdav_lock.db"
  auth.backend = "htdigest"
  auth.backend.htdigest.userfile = "/path/to/xmarks/dir/.passwd"
  auth.require = ( "" => ( "method" => "digest",
                           "realm" => "webdav",
                           "require" => "valid-user" ) )