url     : field=url hash boolean=Q unique=Q
title   : weight=3 index truncate=80 field=caption boolean=S
date    : date=unix
author  : field=author boolean=A
language : field=language boolean=L
headers : weight=2 index field=sample
lastmod : field=lastmod value=1
md5     : field=md5 value=2
size    : field=size value=3
content : index field=sample
